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What`s a Microcontroller Text

1. Vss X2 ACTIVITY 2 INTRODUCING THE DIGITAL POTENTIOMETER In this activity you will replace the manually adjusted potentiometer with an integrated circuit potentiometer that is digitally adjusted You will then program the BASIC Stamp to adjust the digital potentiometer which will in turn adjust the LED s brightness in the same way the manual potentiometer did in the previous activity Page 268 What s a Microcontroller Introducing the Digital Potentiometer Figure 9 5 shows a pin map of the digital potentiometer you will use in this activity This chip has 8 pins four on each side that are spaced to make it easy to plug into a breadboard 1 10 inch apart The manufacturer places a reference notch on the plastic case so that you can tell the difference between pin 1 and pin 5 The reference notch is a small half circle in the chip s case You can use this notch as a reference for the pin numbers on the chip The pin numbers on the chip count upwards counterclockwise from the reference notch Part Substitutions It is sometimes necessary for Parallax to make a part substitution The part will function the same but the label on it may be different If you find that the digital Wb potentiometer included in your What s a Microcontroller Parts Kit is not labeled AD5220 rest assured that it will still work the same way and perform correctly in this activity Ref
2. Vss X2 Can you really do that with the LED Up until now the LED s cathode has always been o amp __ connected to Vss Now the LED is in a different place in the circuit with its anode connected to Vdd People often ask if this breaks any circuit rules and the answer is no ew The electrical pressure supplied by Vdd and Vss is 5 volts The diode will always use 1 6 volts and the resistor will always use 3 4 volts regardless of their order ACTIVITY 2 READING A PUSHBUTTON WITH THE BASIC STAMP In this activity you will connect a pushbutton circuit to the BASIC Stamp and display whether or not the pushbutton is pressed You will do this by writing a PBASIC program that checks the state of the pushbutton and displays it in the Debug Terminal Parts for a Pushbutton Circuit 1 Pushbutton normally open 1 Resistor 220 Q red red brown 1 Resistor 10 kQ brown black orange 2 Jumper wires Building a Pushbutton Circuit for the BASIC Stamp Figure 3 6 shows a pushbutton circuit that is connected to BASIC Stamp I O pin P3 y Build the circuit shown in Figure 3 6 Page 76 What s a Microcontroller Vdd vin Vss Figure 3 6 Pushbutton Circuit Connected to I O Pin P3 X3 P15 Vdd P14 P13 P12 P11 P10 P9 P8 D P3 as P5 220 Q Pi 10 kQ es On the wiring diagram the 220 2 resistor is on the
3. PARALLAX www parallax com Connect the servo to the servo header as shown in Figure 4 11 Make sure that the colors on the servo s cable align properly with the colors labeled in the picture Double check your wiring Reconnect your 9 V battery to your HomeWork Board The servo may move a bit when you make the connection Chapter 4 Controlling Motion Page 111 Vdd Vin ps N Wanga Nta J og oy ag OF Figure 4 11 oigo Connecting Servo to Servo Header on a HomeWork Board PARALLAX www parallax com Move on to Programming Servo Control on page 113 Board of Education Rev B Figure 4 12 shows the schematic for the servo and LED circuits on the Board of Education Rev B The instructions that come after this figure will show you how to safely build this circuit on your Board of Education Rev B WARNING Use only a 9 V battery when your Parallax Standard Servo is connected to the Board of Education Rev B Do not use any kind of DC supply or battery replacer that plugs into an AC outlet Improper use of these devices can cause the activ
4. iq OO oom om 000 PARALLAX www parallax com PARALLAX www parallax com Figure 4 21 Board of Education Rev C Servo Circuit with Pushbutton Circuits Added Figure 4 22 HomeWork Board Servo Circuit with Pushbutton Circuits Added Chapter 4 Controlling Motion Page 131 White gt Red gt Black gt x3 Figure 4 23 P15 Board of Education P14 Rev B Servo at Circuit with P11 Pushbutton Circuits ss 0 Added P8 P7 RE 00g PARALLAX Pa 3 www parallax com Dl a000 S foo V Test the pushbutton connected to P3 using the original version of ReadPushbuttonState bs2 The section that has this program and the instructions on how to use it begins on page 77 y Modify the program so that it reads P4 V Run the modified program to test the pushbutton connected to P4 Programming Pushbutton Servo Control Pushbutton servo control is not much different from pushbutton LED control IF THEN code blocks are used to check the pushbutton states and either add or subtract from a variable called duration This variable is used in the puLSouT command s Duration argument If one of the pushbutto
5. Xx Figure 2 18 P15 Manual bi P14 color LED P13 P12 Test P11 ih Bi color P8 LED red a left and P5 green P4 ight P4 right P2 P1 PO x2 x2 Controlling a bi color LED with the BASIC Stamp requires two I O pins After you have manually verified that the bi color LED works using the manual test you can connect the circuit to the BASIC Stamp as shown in Figure 2 19 V Connect the bi color LED circuit to the BASIC Stamp as shown in Figure 2 19 Vali Vin Vss P15 P12 Figure 2 19 P11 i Bi color LED Connected H a T to BASIC Stamp P14 D i 470 Q P3 X2 Page 64 What s a Microcontroller BASIC Stamp Bi Color LED Control Figure 2 20 shows how you can use P15 and P14 to control the current flow in the bi color LED circuit The upper schematic shows how current flows through the red LED when P15 is set to Vdd and P14 is set to Vss This is because the red LED will let current flow through it when electrical pressure is applied as shown but the green LED acts like a closed valve and does not let current through it The bi color LED glows red The lower schema
6. ccesceeeeeeeteeeeeeeteeees 152 SSUPMIMANY ese sa a5 hveese T Se ledacs a oats E Sees Bie seeer sce eae ds 160 Chapter 6 Digital Display ccsecceseeesseesesseeeneeeeeneeeseseeeeneeeeeeeeeeseeeseseeeenseeeenees 165 The Every Day Digital Display eee cccceeeeeeeeeeeeceeeeeeeeeeeenaeeeeeeeeeeeeenaaeeeeeeeeeseeeaaeeees 165 What s a 7 Segment Display ccccccccceeeeceeeeeeeceeeeeeeeeeeeaeeeeeeeeeeeeeeeeeeeeseneeeeeees 165 Activity 1 Building and Testing the 7 Segment LED Display c seeee 167 Activity 2 Controlling the 7 Segment LED Display cccesseeeeeeeeeeeeeeteeees 171 Activity 3 Displaying Digits ccccccceseeceeeeeeeeeeeeeceeeeeeaeeceeeeeeeeeeaeeeeeeeeeeeesseeeees 174 Activity 4 Displaying the Position of a Dial cc cceeceececeeeeeceeeeseeeeeeeeteeeeeseeeees 181 SUMIMANY 5 c2ccess E ce tetas e eee teat e E E E T 186 Chapter 7 Measuring Light ccsccssssesseeeeseeeeeeeeeseeeseseeeeeeeeeeseeeseseaeenseeeeees 189 Devices that Contain Light Sensors cceeeeeeeceeeeeeeeeeeeeeeeeeaeeeeeeneeeeeeseeeeeeeeaees 189 Introducing the Photoresistor ceceeeececeeeeeeeeeeneeeeeeeeeeeeenaaeeeeeeeeeeeenaeeeeeeeeeseeenaeeees 189 Activity 1 Building and Testing the Light Meter ceececceeeeeeeeeeeeeteeeeeeeeeees 190 Activity 2 Graphing Light Measurements ccce
7. Do not substitute a Parallax Continuous Rotation Servo as it may be quickly damaged by ow the circuits shown below Likewise we do not recommend using other brands of standard hobby servos which may not be rated for use with the voltage supplied in these circuits Building the Dial and Servo Circuits This activity will use two circuits that you have already built individually the potentiometer circuit from the activity you just finished and the servo circuit from the previous chapter V Leave your potentiometer RC time circuit from Activity 3 on your prototyping area If you need to rebuild it use Figure 5 11 on page 150 and Figure 5 12 on page 151 Make sure to use the 0 1 uF capacitor not the 0 01 uF capacitor y Add your servo circuit from Chapter 4 Activity 1 to the project Remember that your servo circuit will be different depending on your carrier board Below are the pages for the sections that you will need to jump to e Page 105 Board of Education Rev C e Page 111 Board of Education Rev B e Page 108 BASIC Stamp HomeWork Board Programming Potentiometer Control of the Servo You will need the smallest and largest value of the time variable that you recorded from your RC time circuit while using a 0 1 UF capacitor y If you have not already completed the Your Turn section of the previous activity go back and complete it now For this next example here are the time values that were measured b
8. SSTAMP BS2 SPBASIC 2 5 counter VAR Word DO DEBUG Pulse width increment by 8 CR FOR counter 500 TO 1000 STEP 8 PULSOUT 14 counter PAUSE 7 DEBUG DECS counter CR CRSRUP NEXT Chapter 4 Controlling Motion Page 127 DEBUG CR Pulse width decrement by 20 CR FOR counter 1000 TO 500 STEP 20 PULSOUT 14 counter PAUSE 7 DEBUG DEC5 counter CR CRSRUP NEXT DEBUG CR Repeat CR LOOP How ServoVelocities bs2 Works The first FOR NExT loop counts upwards from 500 to 1000 in steps of 8 Since the counter variable is used as the PULSOUT command s Duration argument the servo horn s position rotates counterclockwise by steps that are four times the smallest possible step FOR counter 500 TO 1000 STEP 8 PULSOUT 14 counter PAUSE 7 DEBUG DEC5 counter CR CRSRUP NEXT A cn PEN Why PAUSE 7 instead of PAUSE 20 The command DEBUG DEC5 counter CR CRSRUP takes about 8 ms to execute This means that PAUSE 12 would maintain the 20 ms delay between pulses A few trial and error experiments showed that PAUSE 7 gave the servo the smoothest motion Your servo may be different More DEBUG formatters and control characters are featured in the DEBUG command that displays the value of the counter variable This value is printed using the 5 digit decimal format DEC5 After the value is printed there is a carriage return CR After the carriage return the formatter CRSRUP cursor up send
9. Parallax Part Description Quantity 150 01020 Resistor 5 1 4W 1 KQ 10 150 01030 Resistor 5 1 4W 10 kQ 4 150 01040 Resistor 5 1 4W 100 kQ 2 150 02020 Resistor 5 1 4W 2 KQ 2 150 02210 Resistor 5 1 4W 220 Q 6 150 04710 Resistor 5 1 4W 470 Q 6 152 01031 Potentiometer 10 kQ 1 200 01031 Capacitor 0 01 uF 50 V 1 200 01040 Capacitor 0 1 uF 100 V 2 201 01080 Capacitor 1000 uF 10 V 1 201 03080 Capacitor 3300 uF 16 V 1 J i gt 28123 included in 28182 only 1 350 00001 LED Green T1 3 4 2 350 00005 LED Bi Color T1 3 4 1 350 00006 LED Red T1 3 4 2 350 00007 LED Yellow T1 3 4 2 350 00009 Photoresistor 1 350 00027 7 segment LED Display 1 400 00002 Pushbutton Normally Open 2 451 00303 3 Pin Header Male Male 1 500 00001 Transistor 2N3904 1 604 00010 10 kQ digital potentiometer 1 800 00016 3 Jumper Wires Bag of 10 2 900 00001 Piezo Speaker 1 900 00005 Parallax Standard Servo 1 Appendix B Equipment and Parts Lists Page 305 Option 2 e BASIC Stamp What s a Microcontroller Kit 90005 This kit features the What s a Microcontroller Parts amp Text with a HomeWork Board and accessories that are otherwise sold separately The BASIC Stamp HomeWork Board can be used with the What s a Microcontroller text in place of the Board of Education and BASIC Stamp 2 module The HomeWork Board can also be used in the majority of the activities in the Stamps in Class cur
10. c cccessccesseeeeeeeeeeseeesseeseseeeenseeeeseeeseseaeenseeeeees 103 Microcontrolled Motion cccccceeeeeeeeeeeeneeeeeeeeeeeeeaeeeeeeeeeseeeaeeeeeeeeeseeeaeeeeeeeeeteeaaa 103 On Off Signals and Motor Motion ccccccccccceeeeeceeeeeeeeeeeeeeeeeecaeeeeeseeeeeeseneeesseaees 103 Activity 1 Connecting and Testing the Servo cccccceceeeeeeeeeeeeeeeeeeeeeteeeeeeeneees 103 Activity 2 Controlling Position with Your Computer cccceseeceeeeeeeeeeeeeeeeeees 119 Activity 3 Converting Position to Motion cccceccceeeeeceeeeeeeeeeeeeeeeeeeeneeeeeeseeeees 125 Activity 4 Pushbutton Controlled Servo ccceceececeeeeeceeeeeeeeeeeeeeeeeeeseeeessneeees 128 SUMMANRY 2 eE 218 SAA eA PA ee AG nA e ehh a ea hon ea 134 Chapter 5 Measuring Rotation ccccsccssseesseeeeeseeesseeseseeeenseeeeeseeseneenenseeeenes 139 Adjusting Dials and Monitoring Machines cceecseeeeeeeeceeeeeeeeeeenneeeeeeeeeeeeenaeeees 139 The Variable Resistor under the Dial A Potentiometer eceeeceeeeeeeeeeeeenneeeees 139 Activity 1 Building and Testing the Potentiometer Circuit ceeeeeeeeeeereees 141 Activity 2 Measuring Resistance by Measuring Time ces ceeeeeeeeeeeeeteeees 143 Activity 3 Reading the Dial with the BASIC Stamp cceeeseeeeeeeeeeeeeeseeees 149 Activity 4 Controlling a Servo with a Potentiometer
11. new fractional value 185 4 Place that value after the operator Page 156 What s a Microcontroller time time 185 That takes care of the scaling now all we need to do is add the offset of 500 This can be done with a second command that adds 500 to time time time 185 time time 500 Now time is ready to be recycled into the PULSOUT command s Duration argument 3 y y g time time 185 Scale by 0 724 time time 500 Offset by 500 PULSOUT 14 time Send pulse to servo Example Program ControlServoWithPot bs2 y Enter and run this program then twist the potentiometer s input shaft and make sure that the servo s movements echo the potentiometer s movements What s a Microcontroller ControlServoWithPot bs2 Read potentiometer in RC time circuit using RCTIME command Scale time by 0 724 and offset by 500 for the servo SSTAMP BS2 S PBASIC 2 5 DEBUG Program Running time VAR Word DO HIGH 7 PAUSE 10 RCTIME 7 1 time time time 185 Scale by 0 724 X 256 for time time 500 T Oee lo SOO PULSOUT 14 time Send pulse to servo LOOP Your Turn Scaling the Servo s Relationship to the Dial Your potentiometer and capacitor will probably give you time values that are somewhat different from the ones discussed in this activity These are the values you gathered in the Your Turn section of the previous activity y Repeat the math discussed in t
12. y Try downloading a program once more Windows 2000 y Click on your computer desktop s Start button lt ce ee L Appendix E Trouble Shooting Page 317 Select Settings Control Panel System Hardware Device Manager gt Ports COM amp LPT Select the COM port that was noted by the Run Identify test Select Port Settings Advanced Uncheck the box labeled Use FIFO Buffers then click OK Click OK as needed to close each window and return to the BASIC Stamp Editor Try downloading a program once more Windows XP lt cee ee ee se Click on your computer desktop s Start button Select Control Panel Printers and Other Hardware In the See Also box select System Select Hardware Device Manager Ports Enter the COM port number noted by the Run Identify test Select Port Settings Advanced Uncheck the box labeled Use FIFO Buffers then click OK Click OK to close each window as needed and return to the BASIC Stamp Editor Try downloading a program once more Windows XP Pro L L l ee as Click on your computer desktop s Start button Select Control Panel System Hardware Device Manager Ports COM amp LPT1 Select the Communications Port number noted by the Run Identify test Select Properties Port Settings Advanced Uncheck the box labeled Use FIFO Buffers then click OK Click OK to close each window
13. P4 Pressed 2 kHz beep for 1 5 second 2 kHz 2000 Hz g 1 5 e 1000 5 me A00 me P3 Pressed 3 kHz beep for 1 10 second 3 kHz 3000 Hz x 1 10 s 1000 10 ms 100 ms SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running DO IF IN4 1 THEN FREQOUT 9 200 2000 P2000 Hz tor 200 ms ELSEIF IN3 1 THEN FREQOUT 9 100 3000 3000 Hz for 100 ms ENDIF LOOP Further Investigation Applied Sensors Student Guide Version 2 0 Parallax Inc 2003 More sound effects clicks crickets are introduced using the piezoelectric speaker The pentatonic and equal temperament scale are the basis for discussion of math fractions The speaker is also used as feedback for a variety of sensor measurements Basic Analog and Digital Student Guide Version 2 0 Parallax Inc 2003 The speaker is used to make a frequency generated by a 555 timer audible The BASIC Stamp measures the frequency of the tone with a count command Understanding Signals Student Guide Version 1 0 Parallax Inc 2003 You can use this book to view the output of the FREQoUT command both as digital pulses and as sine waves Chapter 9 Electronic Building Blocks Page 263 Chapter 9 Electronic Building Blocks THOSE LITTLE BLACK CHIPS You need look no further than your BASIC Stamp see Figure 9 1 to find examples of those little black chips Each of these chips has a special function The upper right chip is the voltage re
14. RETURN Read_Photoresistor HIGH PhotoPin PAUSE DelayRc RCTIME PhotoPin 1 time DEBUG CLS time m PAUSE DelayReader RETURN Your Turn Modifying Subroutines Terminals are not the only application for on cosuB For example if you want to call the four different subroutines one after another here is a way to do it DO GOSUB Display Menu GOSUB Get_Request FOR request 0 TO 3 ON request GOSUB Read_Pushbutton_1 Read _Pushbutton_2 Read _ Pot Read_Photoresistor NEXT LOOP Notice that the two subroutines that do the terminal work were commented and the ON GOSUB command was placed in a FOR NEXT loop y Save your example program under the new name TerminalOperatedSensorArray YourTurn bs2 V Modify the main routine by making the changes just discussed V Run the program and verify that it cycles through the measurements ACTIVITY 4 DEVELOPING AND ADDING A SOFTWARE SUBSYSTEM Let s say that your sensor array is getting placed in a device that only certain employees are allowed to use and they have to supply a password This means you will have to expand your program so that it saves and verifies a password It s better to write a password program that functions on its own first and then add it to your larger program Page 292 What s a Microcontroller Programming a Password Checker You can save a password in a PBASIC program by using a Data directive For example Password DATA pas
15. Your Turn Using Constants for Calibration and Easy Updating As mentioned earlier if you change the I O pin used by the HIGH and RCTIME command you can simply change the value of the rcPin constant declaration 2a eas L 2 Chapter 5 Measuring Rotation Page 159 Save the example program under a new name Change the scaleFactor and offset values to the unique values for your RC circuit that you determined in the previous Your Turn section Run the modified program and verify that it works correctly Modify your circuit by moving the RC time circuit from I O pin P7 to I O pin P8 Modify the rePin declaration so that it reads rePin CON 8 Add this command before the Do LooP so that you can see that the rcPin constant really is just a way of saying the number eight DEBUG rcPin Re run the program and verify that the HIGH and RCTIME commands are still functioning properly on the different I O pin with just one change to the rcPin con directive Page 160 What s a Microcontroller SUMMARY This chapter introduced the potentiometer a part often found under various knobs and dials The potentiometer has a resistive element that typically connects its outer two terminals and a wiper terminal that contacts a variable point on the resistive element The potentiometer can be used as a variable resistor if the wiper terminal and one of the two outer terminals is used in a circuit The capacitor was also introduced in this ch
16. 4 Place that value after the operator a i Example Le s say you want to multiply the timeCounter variable by 3 69 E 1 Start by placing timeCounter to the left of the operator timeCounter timeCounter 2 Multiply your fractional value by 256 3 69 X 256 944 64 3 Round off 944 64 945 4 Place that value to the right of the operator timeCounter timeCounter 945 Item 2 Players soon figure out that the delay from red to green is 1 second After playing it several times they get better at predicting when to let go and their score no longer reflects their true reaction time The BASIC Stamp has a RANDOM command Here is how to modify your code for a random number N At the beginning of your code add a declaration for a new variable called value and set it to 23 The value 23 is called the seed because it starts the pseudo random number sequence timeCounter VAR Word value VAR Byte lt Add this value 23 lt Add this Just before the pause command use the RANDOM command to give value a new random value from the pseudo random sequence that started with 23 RANDOM value lt Add this DEBUG Delay time 1000 value CR lt Add this Page 96 What s a Microcontroller y Modify the pause command so that the random value is added to 1000 for one second in the PAUSE command s Duration argument PAUSE 1000 value lt Modify this What s an algorit
17. Delete Dato Fie 2400 me m Levels mua 3 w EJ Chew MevMax tae dot JI Grable Shit Time Spar ef J ren Clos Mersozer Save messages tole Deinte Mag Fie This graph could depict any number of scenarios to the technician reading it Perhaps a microcontroller in a greenhouse switched on the artificial lights after the sunlight dropped below a certain level Perhaps a system of motors and gears that maintains a solar panel s position for maximum sunlight exposure just readjusted the panel s position after Page 194 What s a Microcontroller detecting a decrease in light exposure Regardless of the scenario if you are familiar with the measurement being graphed tools like Stamp Plot Lite can really help make sense out of data It does this by converting lists of measurements into a graph N___ Stamp Plot Lite is free for educational use courtesy of SelmaWare Solutions and can be _ __ _ installed from the Parallax CD or downloaded from the Parallax web site or directly from http www selmaware com Downloading and Installing Stamp Plot Lite Before installing Stamp Plot Lite you must have WinZip installed on your PC or laptop WinZip can be installed from the Parallax CD or downloaded from www winzip com Below are instructions for downloading and installing Stamp Plot Lite from the Parallax web site Go to the Downloads area at www parallax com Select BASIC Stamp Software
18. Figure 8 3 shows the rightmost 25 keys of a piano keyboard It also shows the frequencies at which each wire inside the piano vibrates when that piano key is struck The keys and their corresponding notes are labeled C6 through C8 These keys are separated into groups of 12 Each group spans one octave made up of 8 white keys and 4 black keys The sequence of notes repeats itself every 12 keys Notes of the same letter are related by frequency doubling with each higher octave For example C7 is twice the frequency of C6 and C8 is twice the frequency of C7 Likewise if you go one octave down the frequency will be half the value for example A6 is half the frequency of A7 Internet search for musical scale By using the words musical scale in a search e engine like Google or Yahoo you will find lots of fascinating information about the history Wy physics and psychology of the subject The 12 note per octave scale is the main scale of western music Other cultures use scales that contain 2 to 35 notes per octave Page 228 What s a Microcontroller If you ve ever heard a singer practice his her notes by singing the Solfege Do Re Mi Fa Sol La Ti Do the singer is attempting to match the notes that you get from striking the white keys on a piano keyboard These white keys are called natural keys A black key on a piano can either be called sharp or flat For example the black key between the C and D keys is eith
19. s a convenient value for describing the amount of current that a car battery supplies to headlights the fan that cool a car s engine and other high power devices What s Resistance Resistance is the element in a circuit that slows down the flow of electrons the current from a battery s negative terminal to its positive terminal The ohm is the basic measurement of resistance It has already been introduced and it s abbreviated with the Greek letter omega Q What s a Conductor Copper wire has almost no resistance and it s called a conductor Page 320 What s a Microcontroller BONUS ACTIVITY OHMS LAW VOLTAGE AND CURRENT This activity applies some of the definitions just discussed Ohm s Law Parts 1 Resistor 220 Q red red brown 1 Resistor 470 Q yellow violet brown 1 Resistor 1 kQ brown black red 1 Resistor 2 KQ red black red 1 LED any color Test Circuit The resistance value of R in Figure F 1 can be changed Lower resistance allows more current through the LED and it glows more brightly Higher resistance values will cause the LED to look dim because they do not allow as much current to pass through the circuit Disconnect power to your Board of Education or HomeWork Board whenever you modify the circuit Build the circuit shown starting with a 220 Q resistor Modify the circuit by replacing the 220 resistor with a 470 Q resistor Wa
20. 4 4 4 2 2 Dots DATA 0 0 oO Oy Oi Ou Ly oO 0 Oy oO 0 0 Os alae 0 BeatsPerMin CON 320 In the previous example program WholeNote was a constant This time it s a variable that will hold the duration of a whole note in ms After this value is calculated WholeNote will be used to determine all the other note durations just like in the previous program The index offset noteLetter and noteDuration variables are also used in the same manner they were in the previous program The noteFreq variable is handled a little differently since now it has to be adjusted depending on the octave the note is played in The noteOctave and noteDot variables have been added to handle the octave and dot features wholeNote VAR Word index VAR Byte offset VAR Nib noteLetter VAR Byte noteFreq VAR Word noteDuration VAR Word Page 242 What s a Microcontroller noteOctave VAR Nib noteDot VAR Bit The wholeNote variable is calculated using the BeatsPerMin The tempo of the song is defined in beats per minute and the program has to divide BeatsPerMin into 60000 ms then multiply by 4 The result is the correct value for a whole note wholeNote 60000 BeatsPerMin 4 Math executes from left to right In the calculation wholeNote 60000 an beatsPerMin 4 the BASIC Stamp first calculates 60000 beatsPerMin i Then it multiplies that result by 4 Parentheses can be used to group operations If you want to divide 4 into b
21. 45 319 Vss 41 46 323 W What s a Microcontroller Parts Kit 303 Text 303 Word 55 247 WRITE 199 201 1359 02020 350 00005 350 00007 vag ney ha 5 resistors 1 bi color LED 7 2 yellow LEDs h ic oO 350 00027 1 7 segment LED display i 350 00001 150 02210 2 green LEDs Aa 6 220 Q 1 4 W 5 resistors 400 0002 a 2 pushbuttons normally open 4 lead SPST type 350 00009 EE mone W 5 resi 1 photereaisios 350 00006 6 resistors 2 red LEDs A yellow violet brown w W 150 01040 201 03080 2 100 kQ 1 4 W 5 resistors 1 3300 pF electrolytic capacitor brown black yellow ee 1 piezospeaker se 150 01030 200 01040 2 0 1 pF ceramic capacitor 4 10k 1 4 W 5 resistors brown black orange nm i E m 150 01020 800 0016 10 1 KQ 1 4 W 5 resisitors sabre pluggable a Pal A ee 1 1000 pF electrolytic capacitor 4452 01031 1 10 KQ potentiometer a 200 01031 1 0 01 pF poly capacitor 1 3 pin header male male 604 00010 1 10 kQ digitally controlled 900 00005 potentiometer AD5220 1 Parallax Standard Servo my 451 00303 wal 500 00001 1 2N3904 transistor Parts and quantities in the various What s a Microcontroller kits are subject to change without notice Parts may differ from what is shown in this picture Please contact stampsinclass parallax com if you have any questions about your kit
22. CR CR Run the modified program and CR check to see what number the CR LOOKUP command places in the CR value variable END Example Program DisplayDigitsWithLookup bs2 This example program shows how the LOOKUP command can come in really handy for storing the bit patterns used in the ouTH variable Again the index is used to choose which binary value is placed into the ouTH variable This example program counts from 0 to 9 again The difference between this program and DisplayDigits bs2 is that this program is much more versatile It is much quicker and easier to adjust for different number sequences using lookup tables y Enter and run DisplayDigitsWithLookup bs2 y Verify that it does the same thing as the previous program with much less work y Take a look at the Debug Terminal while the program runs It shows how the value of index is used by the LOOKUP command to load the correct binary value from the list into oUTH What s a Microcontroller DisplayDigitsWithLookup bs2 Use a lookup table to store and display digits with a 7 segment LED display SSTAMP BS2 SPBASIC 2 5 index VAR Nib OUTH 300000000 DIRE SLT LET ELT DEBUG index OUTH Whe OR FOR index 0 TO 9 LOOKUP index 11100111 10000100 11010011 11010110 10110100 01110110 Chapter 6 Digital Display Page 181 01110111 11000100 11110111 11110110 J OUTH DEBUG Ti IDIZIeAy aliaysley e 1 W jshicihie
23. Download the file labeled Stamp Plot Lite graphing utility Save StampPlot zip to your disk Open StampPlot zip by double clicking it If you are using the WinZip wizard follow the screen prompts and it will run the installation program If you are using WinZip classic you will have to double click Setup exe to start the installation y Follow the Stamp Plot Lite installation program s prompts to install the software L Ll Ll Ll L Ll Programming to Send Measurements to Stamp Plot Lite Sending values you want to graph in Stamp Plot Lite is almost the same as sending numbers to the Debug Terminal but there are a few rules First values are sent using only the DEC formatter and the cR control character We want to plot the value of the time variable so all that should be sent to the Debug Terminal is the decimal value followed by a carriage return DEBUG DEC time CR You can also send display settings to Stamp Plot Lite by sending special messages in quotes These messages are called control codes Control codes are sent to Stamp Plot Lite at the beginning of a PBASIC program Although you can click and adjust all the settings on the software itself it is usually easier to program the BASIC Stamp to tell Chapter 7 Measuring Light Page 195 Stamp Plot Lite those settings for you Here is an example of some configuration settings from the next example program that will make your RC time measurements easier to read w
24. Program Running index VAR Nib time VAR Word OUTH 00000000 DIRE Fa ALLL aa al DO HIGH 5 PAUSE 100 RCTIME 5 1 time LOOKDOWN time lt 40 150 275 400 550 800 index Chapter 6 Digital Display Page 185 LOOKUP index 11100101 11100001 01100001 00100001 00000001 00000000 OUTH LOOP How DialDisplay bs2 Works This example program takes an RCTIME measurement of the potentiometer and stores it in a variable named time HIGH 5 PAUSE 100 RCTIME 5 1 time The time variable is then used in a LOOKDOWN table The Looxpown table decides which number in the list time is smaller than then loads the entry number 0 to 5 in this case into the index variable LOOKDOWN time lt 40 150 275 400 550 800 index Then the index variable is used in a LOoKuP table to choose the binary value to load into the ouTH variable LOOKUP index 11100101 11100001 01100001 00100001 00000001 00000000 OUTH Your Turn Adding a Segment DialDisplay bs2 only makes five of the six segments turn on when you turn the dial The sequence for turning the LEDs on in DialDisplay bs2 is E F A B C but not D y Save DialDisplay bs2 under the name DialDisplayY ourTurn bs2 y Modify DialDisplayYourTurn bs2 so that it causes all six outer LEDs to turn on in sequence as the potentiometer is turned The sequence should be E F A B C and D Page 186 What s a Microcontroller SUMMARY This ch
25. Run TestSecondLED bs2 Make sure the LED circuit connected to P15 is flashing If the LED connected to P15 flashes move on to the next example Controlling Both LEDs If the LED circuit connected to P15 is not flashing check your circuit for wiring errors and your program for typing errors and try again lt lt es What s a Microcontroller TestSecondLed bs2 Turn LED connected to P15 on and off Repeat 1 time per second indefinitely SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running Chapter 2 Lights On Lights Off Page 59 DO HIGH 15 PAUSE 500 LOW 15 PAUSE 500 LOOP Controlling Both LEDs Yes you can flash both LEDs at once One way you can do this is to use two HIGH commands before the first PAUSE command One HIGH command sets P14 high and the next HIGH command sets P15 high You will also need two Low commands to turn both LEDs off It s true that both LEDs will not turn on and off at exactly the same time because one is turned on or off after the other However there is no more than a millisecond s difference between the two changes and the human eye will not detect it Example Program FlashBothLeds bs2 V Enter the FlashBothLeds bs2 code into the BASIC Stamp Editor V Run the program y Verify that both LEDs appear to flash on and off at the same time What s a Microcontroller FlashBothLeds bs2 Turn LEDs connected to P14 and P15 on and off SSTAMP BS2 PBASIC 2 5
26. The battery s negative terminal contains a compound that has molecules with extra electrons shown in Figure 2 7 by minus signs The battery s positive terminal has a chemical compound with molecules that are missing electrons shown by plus signs When an electron leaves a molecule in the negative terminal and travels through the wire it is called a free electron also shown by minus signs The molecule that lost that extra electron no longer has an extra negative charge it is now called neutral Shown by an N When an electron gets to the positive terminal it joins a molecule that was missing an electron and now that molecule is neutral too Figure 2 8 shows how the flow of electricity through the LED circuit is described using schematic notation The electric pressure across the circuit is called voltage The and signs are used to show the voltage applied to a circuit The arrow shows the current flowing through the circuit This arrow is almost always shown pointing the opposite direction of the actual flow of electrons Benjamin Franklin is credited with not having been aware of electrons when he decided to represent current flow as charge passing from the positive to negative terminal of a circuit By the time physicists discovered the true nature of electric current the convention was already well established Figure 2 8 Voltage uae LED On Circuit Schematic Showing Resistance Conventional Voltage and Current F
27. V To make sure your BASIC Stamp module is communicating with your computer click the Run menu then select Identify Y BASIC Stamp C Program Files Parallax Inc Stamp Editor v2 0 Beta 1 BS2 FirstProgram bs2 Bj x File Edit Directive Run Help De a amp Run Ctrl Check Syntax Ctrl T Ee f Deteuk 852 Direc Memory Map Ctrl M Bie ee 23 SEER KKKE O al sA a Debug gt BS2e X 4 gt DATA bs2 A DTMFOUT bs2 FirstProgram bs2 FORNEXT bs2 gt BASIC Stamp files bs2 bse bsx bsp 1 7 4 identity firmware revision of the BASIC Stamp Figure 1 31 BASIC Stamp Editor Select Identify from the Run menu An Identification window similar to the one shown in Figure 1 32 will appear The example in the figure shows that a BASIC Stamp 2 has been detected on COM2 y Check the Identification window to make sure a BASIC Stamp 2 module has been detected on one of the COM ports If it has been detected then you are ready for Activity 4 First Program If the Identification window does not detect a BASIC Stamp 2 module on any of the COM ports go to Appendix E Trouble Shooting on page 315 A 3 Status Figure 1 32 oa jE Identification Window No No cow EtPo Beten 2 found on COM2 COM2 BASIC Stamp 2 v0 Yes Yes z Example BASIC Stamp Page 20 What s a Microcontroller ACTIVITY 4 FIRST PROGRAM The first progr
28. a very brief high signal using a BASIC Stamp I O pin Here is the command syntax for the PULSOoUT command PULSOUT Pin Duration As with HIGH and Low the Pin argument is a number that tells the BASIC Stamp which T O pin the signal is sent on The Duration argument is not milliseconds like it is in the PAUSE command For the BASIC Stamp 2 the Duration is the number of 2 millionth of a second us time durations that you want the high signal to last Page 114 What s a Microcontroller A millionth of a second is called a microsecond The Greek letter u is used in place of the word micro and the letter s is used in place of second This is handy for writing and taking notes because instead of writing 2 microseconds you can write 2 us Reminder one thousandth of a second is called a millisecond and is abbreviated ms Fact 1 ms 1000 ps In other words you can fit one thousand millionths of a second into one thousandth of a second The next example program will use the puLSouT command to deliver pulses that instruct the servo on where to position its horn FOR NEXT loops are used to deliver a certain number of pulses which cause the servo to hold a position for a certain amount of time Example Program ServoTest bs2 ServoTest bs2 will make the servo s horn start at somewhere in the neighborhood of 10 o clock and hold that position for about three seconds Then the program will move the servo ho
29. addition we highly recommend that you visit www parallax com and check out our many free downloads and applications for industry professionals educators students hobbyists and the naturally curious Appendix A USB to Serial Adapter Page 301 Appendix A USB to Serial Adapter At the time of this writing the US232B LC USB to Serial Adapter made by Future Technology Devices International is the recommended adapter for use with Parallax products The US232B LC comes with the hardware shown in Figure A 1 and a mini CD ROM with drivers for use with various operating systems including Microsoft Windows Figure A 1 FTDI s re US232B LC USB gt to Serial Adapter This adapter is Parallax Stock 800 00030 It comes with a software CD not shown asm US232B LC Driver Software Downloads The software drivers and other information about wy this product can be downloaded from http www ftdichip com FT232 htm Appendix B Equipment and Parts Lists Page 303 Appendix B Equipment and Parts Lists Parts lists are subject to change Please note that the part numbers and bills of materials cited in this appendix are subject to change without notice If you have questions about a bh particular part or quantity please contact the Parallax using www parallax com Company Contact Parallax link or email stampsinclass parallax com To complete the exercises in this book you need to
30. built on the prototyping area The breadboard is separated into rows of five sockets Each row can connect up to five leads or wires to each other For this circuit the resistor and the LED are connected because each one has a lead plugged into the same 5 socket row Note that one lead of the resistor is plugged into Vdd so the circuit can draw power The other resistor lead connects to the LED s anode lead The LED s cathode lead is connected to Vss or ground completing the circuit You are now ready to build the circuit shown in Figure 2 6 below by plugging the LED and resistor leads into sockets on the prototyping area Follow these steps Disconnect power from your Board of Education or HomeWork Board Use Figure 2 4 to decide which lead is connected to the LED s cathode Look for the shorter lead and the flat spot on the plastic part of the LED Plug the LED s cathode into one of the black sockets labeled Vss on the prototyping area Plug the LED s anode the other longer lead into the socket shown on the breadboard portion of the prototyping area Plug one of the resistor s leads into the same breadboard row as the LED s anode This will connect those two leads together a A a AA Chapter 2 Lights On Lights Off Page 43 Plug the resistor s other lead into one of the sockets labeled Vdd Direction does matter for the LED but not for the resistor If you plug the LED in backward the LED will no
31. circuit is only on for half as long 1 out of 21 ms instead of 2 out of 22 ms 4 What s a Microcontroller ServoTest bs2 Test the servo at three different position signals S STAMP BS2 SPBASIC 2 5 counter VAR Word DEBUG Counterclockwise 10 o clock CR FOR counter 1 TO 150 PULSOUT 14 1000 PAUSE 20 NEXT DEBUG Clockwise 2 o clock CR FOR counter 1 TO 150 PULSOUT 14 500 PAUSE 20 NEXT DEBUG Center 12 o clock CR FOR counter 1 TO 150 PULSOUT 14 750 PAUSE 20 NEXT DEBUG All done END How ServoTest bs2 Works The first FOR NEXT loop delivers 150 pulses each of which lasts 2 0 ms These pulses instruct the servo to go to a position that is roughly 10 o clock if you think about it in terms of a clock face FOR counter 1 TO 150 Page 116 What s a Microcontroller PULSOUT 14 1000 PAUSE 20 NEXT i PULSOUT 14 1000 sends a pulse that lasts 1000 x 2 us That s 2000 us or 2 ms v Figure 4 15 is called a timing diagram It shows a picture of the high and low signals and how long they last The timing diagram does not show how many pulses are delivered but it does give you information about how long the high and low signals last Each pulse high signal lasts for 2 0 ms Each pulse is separated by a 20 ms delay while the signal is low a Figure 4 15 Ike 2 0ms Timing Diagram for Vdd 5 V alas 2 0 ms Pulses Every 20 ms Servo horn in 10 yS 0V o c
32. collecting surface of the photoresistor to different light levels When the example program is running the Debug Terminal should display small values for bright light conditions and large values for low light conditions V Enter and run TestPhotoresistor bs2 V While watching the value of the time variable on the Debug Terminal note the value under normal lighting conditions V Turn the lights in the room off or cast a shadow over the circuit with your hand and check the time variable again It should be a significantly larger number y If you face the photoresistor s light collecting surface toward direct sunlight the time variable should be fairly small What s a Microcontroller TestPhotoresistor bs2 Read photoresistor in RC time circuit using RCTIME command S STAMP BS2 S PBASIC 2 5 time VAR Word DO HIGH 2 PAUSE 100 RYCHUINMIS 2 aly CIME DEBUG HOME time DECS time LOOP Your Turn Using a Different Capacitor for Different Light Conditions Replacing the 0 01 uF capacitor with a 0 1 uF capacitor can be useful for more brightly lit rooms or outdoors The time measurements with the 0 1 uF capacitor will take ten times as long which means the value of the time variable displayed by the Debug Terminal should be ten times as large y Modify the circuit by replacing the 0 01 uF capacitor with a 0 1 uF capacitor y Re run TestPhotoresistor bs2 and verify that the RC time measurements are roughly ten tim
33. however any note could be dotted which means the duration might have to be multiplied by 1 5 A READ command is used to access values stored in EEPROM by the Dots DATA directive An IF THEN statement is used to multiply by 3 and divide by 2 whenever the value of the noteDot variable is 1 READ Durations index noteDuration noteDuration WholeNote noteDuration READ Dots index noteDot IF noteDot 1 THEN noteDuration noteDuration 3 2 Page 244 What s a Microcontroller Integer math The BASIC Stamp does not automatically process a number like 1 5 When performing math it only works with integers 5 4 3 2 1 0 1 2 3 The best solution for multiplying by 1 5 is to multiply by 3 2 First multiply by 3 and then divide by 2 AN There are many ways to program the BASIC Stamp to handle fractional values You can ali program the BASIC Stamp to use integers to figure out the fractional portion of a number This is introduced in the Basic Analog and Digital Student Guide There are also two operators that make fractional values easier to work with and they are and These are explained in detail in the Applied Sensors Student Guide and in the BASIC Stamp Manual The remainder of this example program works the same way that it did in the previous example program FREQOUT 9 noteDuration noteFreq index index 1 LOOP END Your Turn Playing a Tune with More than One Octave
34. si AS SO oss You can always convert from the character representing a digit to to its value by subtracting 48 from the variable storing the digit You can examine this by comparing DEBUG DEC 49 and DEBUG 49 The characters 0 GetTempo default_b 0 DO READ RTTTL File counter char PRECHA CESA default _b THEN default_b 10 counter counter 1 EXIT ENDIF default b default_b char 48 counter counter 1 default_b LOOP UNTIL char RETURN Subroutine ProcessOctave READ RTTTL File SELECT char default_b 10 took Ug OeisehyS counter char CASE 5 TO 8 noteOctave char Qo counter counter 1 CASE ELSE noteOctave ENDSELECT IF default_o default_o 0 THEN default_o noteOctave ENDIF Parse RTTTL file for Tempo Convert characters to digits by subtracting 48 from each character s ASCII value Iteratively multiply each digit by 10 if there is another digit then add the most recent digit to one s column For example the string W120 he IX 40 38 10 2 X 10 0 aways Walt is converted first then multiplied by 10 The 2 is then converted added 0 is converted added done Octave may or may not be included in a given note because any note that is played in the default octave does not specify elas OYSIEEHES IIE al Claveue TEOM TSU icy VOU Nan WSIS de elge use cdareult Characters are conve
35. 1 digit to the ones column READ RTTTL File counter char SELECT char CASE 6 2 n duration duration 10 char 48 counter counter 1 ENDSELECT CASE ELSE 0 Gtie ime Ghoieeiealeimy EUSE duration default_d use default ENDSELECT IF default_d lt gt 0 THEN 1 ie Cereali Cl mot Cerine duration 60000 default_b duration 3 if default_d 0 then ELSE set default_d to the default_d duration duration from the d Chapter 8 Frequency and Sound Page 255 ENDIF RETURN Subroutine Check For Indicating 1 5 Duration CheckForDot Check for dot indicating multiply duration by 3 2 READ RTTTL File counter char If dot found multiply by SELECT char 3 2 and increment counter CAS Fea else do nothing and duration duration 3 2 return counter counter 1 ENDSELECT RETURN PlayNote Find last comma in the U CUrrenC NOCO ENEY Then READ RTTTL_File counter char fetch the note frequency SELECT char from data and play it or CASE a 1 pews brk riecteney Oo counter counter 1 READ Octave8 index 2 Word noteFreq n te ctave 8 n teOctave noteFreq noteFreq DCD noteOctave IF noteFreq 0 THEN PAUSE duration ELSE FREQOUT SpeakerPin duration noteFreq ENDIF ENDSELECT RETURN How MicroMusicWithRtttl bs2 Works This example program is fun to use and it shows the kind of code you will be able to write with
36. 294 What s a Microcontroller DEBUGIN STR userEntry 5 FOR index 0 TO 4 READ Password index temp Get user input password Check array against DATA Get next password char IF temp lt gt userEntry index THEN EXIT Compare to user input NEXT exit if not equal IF index lt gt 5 THEN If exit then index not equal DEBUG CR Password not correct CR to 5 and pass is not correct ENDIF LOOP UNTIL index 5 Only get out of loop when i anaie a Sa DEBUG CR Password is correct CR Program can move on when program can continue password is correct END Your Turn Modifying Passwords y Modify the Password DATA directive so that it uses a different five character password y By changing five different values in the program you can also modify it so that it accepts a four character password instead of a five character password Modifying Password Checker for Use in a Larger Program The goal is to make it easy to fit the PasswordChecker bs2 program into the example program from Activity 3 Two things will help First the password checking program should be modified so that it does most of its work in a subroutine The different parts of the program should also be labeled with commented headings to help make it clear how to combine the two programs Example Program ReusablePasswordChecker bs2 ReusablePasswordChecker bs2 works the same as PasswordChecker bs2 but it now uses a subroutine to do the wo
37. 4 DO UNTIL noteLetter Q READ Notes index noteLetter LOOKDOWN noteLetter E eu ngau Win Met Md mAh The Gi Walls pU Sut Wie HON LOOKUP offset 4186 4435 4699 4978 5588 5920 6272 6645 TAS OE T9902 OF 0 READ Octaves index noteOctave noteOctave 8 noteOctave noteFreq noteFreq DCD noteOctave READ Durations index noteDuration noteDuration WholeNote noteDuration READ Dots index noteDot IF noteDot 1 THEN noteDuration MAT See Se Se D LLAP Tes ae er We Ds 25 4 25 any OF OF OF WEA Myla offset 5274 7040 noteFreq noteDuration 3 2 D Chapter 8 Frequency and Sound Page 241 FREQOUT 9 noteDuration noteFreqg index index 1 LOOP END How MusicWithMoreFeatures bs2 Works Below is the musical data for the entire song For each note in the Notes DATA directive there is a corresponding entry in the Octaves Durations and Dots DATA directives For example the first note is a C note in the 7 octave it s a quarter note and it s not dotted Here is another example the second from the last note not including Q is an E note in the 7 octave It s a half note and it is dotted There is also a BeatsPerMin constant that sets the tempo for the song Notes DATA CU gn TE nE p E npn EN EN D D WDM VC tD MEM TC NON Octaves DATA iy dey 7 ey Ts Iy hy Zs Toy Ty hy ig ae dey Ta 7 Durations DATA 4 2 4 4 4 4 2s 2 4 Da 4
38. 50 66 is the ASCII code for capital B 65 is the code for capital A and so on 32 is the code for a space between characters Notice that each code number was separated with a comma The commas allow the one instance of DEBUG to execute each symbol as a separate command This is much easier to type than 12 separate DEBUG commands Your Turn Exploring ASCII Code y Save ASCIIName bs2 as ASCII Random bs2 y Pick 12 random numbers between 32 and 127 y Replace the ASCII code numbers in the program with the numbers you chose V Run your modified program to see what you get The BASIC Stamp Manual Appendix A has a chart of ASCII code numbers and their corresponding symbols You can look up the corresponding code numbers to spell your own name y Save ASCIIRandom bs2 as YourASCIIName bs2 V Look up the ASCII Chart in the BASIC Stamp Manual y Modify the program to spell your own name V Run the program to see if you spelled your name correctly y If you did good job and save your program ACTIVITY 7 WHEN YOU RE DONE It s important to disconnect the power from your BASIC Stamp and Board of Education or HomeWork Board First your batteries will last longer if the system is not drawing power when you re not using it Second soon you will build circuits on the Board of Education or HomeWork Board prototyping area O ___ Circuit prototypes should never be left unattended with a battery or power supply c
39. 7 segment LED display it takes 8 I O pins to instruct the device what to do Parallel Bus The wires that transmit the HIGH LOW signals from the BASIC Stamp to the 7 segment LED display are called a parallel bus Note that these wires are drawn as parallel lines in Figure 6 10 The term parallel kind of makes sense given the geometry of the schematic Programming the 7 Segment LED Display Test The HIGH and Low commands will accept a variable as a pin argument To test each segment one at a time simply place the HIGH and Low commands in a FOR NEXT loop and use the index to set the I O pin high then low again N N Ni Enter and run SegmentTestWithHighLow bs2 Verify that every segment in the 7 segement LED display lights briefly turning on and then off again Record a list of which segment each I O pin controls Example Program SegmentTestWithHighLow bs2 What s a Microcontroller SegmentTestWithHighLow bs2 Individually test each segment in a 7 Segment LED display Page 174 What s a Microcontroller SSTAMP BS2 SPBASIC 2 5 pinCounter VAR Nib DEBUG I O Pin CR Woes Be me OCR FOR pinCounter 8 TO 15 DEBUG DEC2 pinCounter CR HIGH pinCounter PAUSE 1000 LOW pinCounter NEXT Your Turn A Different Pattern Removing the command Low pinCounter will have an interesting effect y Comment the Low pincounter command by adding an apostrophe to the left of it V Run the modified p
40. 9 V battery extension Although it cannot hurt the BASIC Stamp Board of Education or Homework Board it can destroy the Parallax Standard Servo connected to Vin in a matter of seconds The only system that can protect the servo from this mistake is the Board of Education Rev C with jumper set to Vdd Figure D 3 Polarity on Universal Adapters Beware of Battery Replacers Many battery replacers are designed to supply appliances with low current draw With current ratings in the neighborhood of 10 mA their output capacities are insufficient for many of the activities in this text For example two LEDs connected to 220 Q resistors draw a total of 14 5 mA and the BASIC Stamp takes an additional 3 to 7 mA A servo draws upwards of 100 mA and that definitely won t work with a battery replacer NOTE It s pretty easy to tell when a circuit is drawing more current that the supply can deliver because the Pwr LED on the Board of Education or HomeWork Board flickers and or goes dim Appendix E Trouble Shooting Page 315 Appendix E Trouble Shooting Here is a list of things to try to quickly fix any difficulties getting the BASIC Stamp Editor to communicate with the BASIC Stamp If you are using a Board of Education Rev C make sure the power switch is set to position 1 Rule out dead batteries and incorrect or malfunctioning power supplies by using anew 9 V battery Make sure the serial cable is
41. Chapter 8 Frequency and Sound Page 239 Octaves DATA 6 7 6 6 6 6 6 6 6 Ty 6 Figure 8 4 Rightmost Piano Keys and Their Frequencies 1108 7 1244 5 1480 0 1661 2 1864 7 1217 5 2489 0 2960 0 3322 4 3729 3 G F 6 7 or or A G 6 7 b b Example Program MusicWithMoreFeatures bs2 This example program plays the first few notes from For He s a Jolly Good Fellow All the notes come from the same 7 octave but some of the notes are dotted In the Your turn section you will try an example that uses notes from more than one octave and dotted notes V Enter and run Music WithMoreFeatures bs2 V Count notes and see if you can hear the dotted 1 2 duration notes Also listen for notes in octave 7 Try changing one of those notes to octave 6 The change in the way the music sounds is pretty drastic What s a Microcontroller MusicWithMoreFeatures bs2 Play the beginning of For He s a Jolly Good Fellow Page 240 What s a Microcontroller SSTAMP BS2 S PBASIC 2 5 DEBUG Program Running Notes DATA ete Uae Wi Wilt lho ish mp A Cn z D 5 E z Cn i wow Octaves DATA ies ie We Ws Ws TRR ee Hee Hee 7 Durations DATA a 25 Au A a An 4 4 4 25 a Dots DATA OF OF OF OF 0 0 OF oO T 0 BeatsPerMin CON 320 index VAR Byte offset VAR Nib noteLetter VAR Byte noteFreq VAR Word noteDuration VAR Word noteOctave VAR Nib noteDot VAR Bit wholeNote VAR Word wholeNote 60000 BeatsPerMin
42. DEBUG Program Running DO HIGH 14 HIGH 15 PAUSE 500 LOW 14 LOW 15 PAUSE 500 LOOP Page 60 What s a Microcontroller Your Turn Alternate LEDs You can cause the LEDs to alternate by swapping the HIGH and Low commands that control one of the I O pins This means that while one LED is on the other will be off y Modify FlashBothLeds bs2 so that the commands between the Do and LOOP keywords look like this HIGH 14 LOW 15 PAUSE 500 LOW 14 HIGH 15 PAUSE 500 V Run the modified version of FlashBothLeds bs2 and verify that the LEDs flash alternately on and off ACTIVITY 5 USING CURRENT DIRECTION TO CONTROL A BI COLOR LED The device shown in Figure 2 15 is a security monitor for electronic keys When an electronic key with the right code is used the LED changes color and a door opens This kind of LED is called a bi color LED This activity answers two questions 1 How does the LED change color 2 How can you run one with the BASIC Stamp Chapter 2 Lights On Lights Off Page 61 Figure 2 15 Bi color LED ina Security Device When the door is locked this bi color LED glows red When the door is unlocked by an electronic key with the right code the LED turns green Introducing the Bi Color LED The bi color LED s schematic symbol and part drawing are shown in Figure 2 16 lt _ Figure 2 16 4 nals Bi color LED Icolor Redl Creen 1f 2 Schematic symbol left and part drawing
43. E Bes Microcontrollers i Products Education Robo z Figure 1 8 Toll free sales 888 512 1024 Looking for a BASIC Stamp a of our featured BASIC Stamps Meet your every Stamp need The Parallax Web Site BASIC Stamps Robot Kits Programming Books arallax Microcontrollers www parallax com Component Shop ERE or first time visitors Parallax provides microcontrollers Browse All Products encata aa Orammed in PBASIC Java and Assembly RESOURCES anguage New to BASIC Stamps iltera Stratix Development Tools arallax is offering new Altera Development Tools for the Stratix Chip The Stratix Smart Pack 525 and Stratix Smart Pack S10 are in stock himl_pages downloads software software_basic_stamp asp _ nena Chapter 1 Getting Started Page 7 V When you get to the BASIC Stamp Software page find the most recent version of the BASIC Stamp Windows Editor download with a version number of 2 0 or higher V Click the Download icon In Figure 1 9 the download icon looks like a file folder to the right of the description BASIC Stamp Windows Editor version 2 0 Beta 1 6MB Z Parallax Downloads Software Microsoft Internet Explorer dering Information ee Go Figure 1 9 Home Products Education Robotics Resources Downloads Support Company Toll free sales 888 512 1024 The Parallax Web Site Looking for a BASIC Stamp Cli eatured BASIC Stamps Meet your every Stamp
44. Education X4 Vdd V X3 y Examine the labeling on your carrier board and figure out whether you have a HomeWork Board or a Board of Education Rev B or Rev C y Skip to instructions for connecting the servo to the BASIC Stamp on your carrier board e Page 105 Board of Education Rev C e Page 108 BASIC Stamp HomeWork Board e Page 111 Board of Education Rev B Board of Education Rev C Figure 4 3 shows the schematic of the circuit you will build on the Board of Education Rev C Page 106 What s a Microcontroller P14 470 Q Vss Figure 4 3 Vdd Servo and LED Indicator Schematic for Board of Education Rev C y Tum off the power as shown in Figure 4 4 ee e Reset Figure 4 4 Disconnect E Power Figure 4 5 shows the servo header on the Board of Education Rev C This is where you will plug in your servo This board features a jumper that you can use to connect the servo s power supply to either Vin or Vdd The jumper is the removable black rectangular piece right between the two servo headers y Set the jumper to Vdd as shown in Figure 4 5 This involves lifting the rectangular jumper up off of the pins it is currently on and replacing it on the two pins closest to the Vdd label Chapter 4 Controlling Motion Page 107 15 14 Vdd 13 12 X4 X5 Vin Figure 4 5 Servo Red Header Black Jumper Set to Vdd The jumper allows you to choose the power s
45. HIGH 7 DEBUG Capacitor Charging CR FOR counter 5 TO 0 PAUSE 1000 DEBUG DEC2 counter CR CRSRUP NEXT DEBUG CR CR Measure decay time now CR CR INPUT 7 DO PAUSE 100 timeCounter timeCounter 1 Chapter 5 Measuring Rotation Page 147 DEBUG IN7 DEBUG DEC5 timeCounter CR CRSRUP CRSRUP LOOP UNTIL IN7 0 DEBUG CR CR CR The RC decay time was DEC timeCounter CR tenths of a second CR CR END How PolledRcTimer bs2 Works Two variables are declared The timeCounter variable is used to track how long it takes the capacitor to discharge through R The counter variable is used to count down while the capacitor is charging timeCounter VAR Word counter VAR Nib The command DEBUG cts clears the Debug Terminal so that it doesn t get cluttered with successive measurements HIGH 7 sets P7 high and starts charging the capacitor then a Capacitor charging message is displayed After that a FoR NEXT loop counts down while the capacitor is charging As the capacitor charges the voltage across its terminals increases toward anywhere between 2 5 and 4 9 V depending on the value of Ri DEBUG CLS HIGH 7 DEBUG Capacitor Charging CR FOR counter 5 TO 0 PAUSE 1000 DEBUG DEC2 counter CR CRSRUP NEXT A message announces when the decay starts getting polled DEBUG CR CR Measure decay time now CR CR In order to let the capacitor discharge itself through the R resisto
46. LightMeter bs2 so that the circular pattern displayed by the 7 segment LED display goes in the opposite direction Page 216 Project What s a Microcontroller In an earlier chapter you used a pushbutton to make an LED blink Instead of using a pushbutton use a photoresistor to make the LED blink when you cast a shadow over it Hint You can use an IF THEN statement and the greater than less than operators to decide if your time measurement is above or below a certain value The operator gt is used for greater than and the operator lt is used for less than Solutions Q Q2 Q3 Q4 Q5 Q6 Q7 Q9 El E2 Pressure position rotation temperature smoke vibration tilt light and almost anything else you may think of humidity g force flexion flow rate the list goes on Cadmium sulfide CdS Both devices have varying resistance values The photoresistor s resistance varies according to the light level falling upon it unlike the potentiometer which only changes when the knob is turned Electrically Erasable Programmable Read Only Memory 2048 bytes 2048 x 8 16 384 bits To store a value WRITE To retrieve a value READ The READ command requires a variable A label is a name that can be used as a placeholder in a PBASIC program A subroutine is a small segment of code that does a certain job Calling cosus ending RETURN Schematic based on Figure 7 2 on page 191
47. Microcontroller For example if you didn t already know that the PULSOUT argument for 1 5 ms is 750 here is how you could calculate it Duration 1 5500 750 You can also figure out the Duration of a mystery PULSOUT command using this equation Duration numb er of ms 500 For example if you see the command PuLsouT 14 850 how long does that pulse really last number of ms R 500 1 7 ms Your Turn Adjusting Position and Hold Time The number of times each FOR NEXT loop repeats is what controls how long the servo stays in a given position The value of the PULSOUT command s Duration argument controls where the servo turns to It s important to experiment with changing these values to be sure how they work before moving on to the next experiment V Save ServoTest bs2 as ServoTestYourTurn bs2 y Modify all the FOR NEXT loops so that they execute half as many times as the original program FOR counter 1 to 75 V Run the modified program and verify that the servo holds each position for half as long y Modify all the FOR NEXT loops so that they execute twice as many times as the original program FOR counter 1 to 300 V Run the modified program and verify that the servo holds each position for twice as long y Modify the puLSouT command in the first loop so that it reads Chapter 4 Controlling Motion Page 119 PULSOUT 14 850 Modify the puLsouT command in the second loop so th
48. MusicWithMoreFeatures bs2 made use of rests but it stayed in one octave The tune Take Me Out to the Ball Game shown below plays most of its notes in the 6 octave There are two notes in the 7 octave and they make a big difference to the way it sounds y Save the example program under the name Music WithMoreFeaturesY ourTurn bs2 y Modify the program by replacing the four data directives and one constant declaration with these Notes DATA nen nen A G E G D ph nen en A Gn ngn nG g Octaves DATA 6 7 6 6 6 6 6 6 6 Ty 6 6 6 6 Durations DATA 27 4 4 4 4 24 2 4 2 4 4 4 4 2 Dots DATA O 0 0 0 oO Ty 0 0z 0 0 Oy 0 0 1 BeatsPerMin CON 240 V Run the program and verify that it sounds right Chapter 8 Frequency and Sound Page 245 Those two notes in the 7 octave are essential for making the tune sound right It s interesting to hear what happens if those 7 values are changed to 6 y Try changing the two 7 values in the Octaves DATA directive so that they are 6 Keep in mind this will make Take Me out to the Ball Game sound weird V Run the program and listen to the effect of the wrong octaves on the song y Change the Octaves DATA back to its original state V Run the program again and listen to see if it sounds correct again ACTIVITY 5 CELL PHONE RINGTONES Many cell phones play music that can be downloaded from web pages The computer sends the data about
49. ON GOSUB You can use these commands to jump to labels A label must end with a colon and for the sake of style separate words with the underscore character When picking a name for a label make sure not to use a reserved word The rest of the rules for a label name are the same as the ones for naming variables listed in the information box on page 53 Example Program SimpleSubroutines bs2 This example program shows how subroutines work by sending messages to the Debug Terminal y Examine SimpleSubroutines bs2 and try to guess the order in which the DEBUG commands will be executed y Enter and run the program y Compare the program s actual behavior with your predictions What s a Microcontroller SimpleSubroutines bs2 Demonstrate how subroutines work S STAMP BS2 0 PBASIC 2 5 DO DEBUG CLS Start main routine CR Page 208 What s a Microcontroller PAUSE 2000 GOSUB First Subroutine DEBUG Back in main CR PAUSE 2000 GOSUB Second Subroutine DEBUG Repeat main CR PAUSE 2000 LOOP First_Subroutine DEBUG Executing first DEBUG subroutine CR PAUSE 3000 RETURN Second Subroutine DEBUG Executing second DEBUG subroutine CR PAUSE 3000 RETURN How SimpleSubroutines bs2 Works Figure 7 12 shows how the First Subroutine call in the main routine the DO LOOP works The command GosuB First Subroutine sends the program to the First Subroutine label
50. Show Page 293 This next example program places the DEBUGIN command the FOR NEXT loop and the IF THEN statement inside a DO LOOP UNTIL statement that keeps executing until the value of index gets to 5 indicating the correct password was entered Example Program PasswordChecker bs2 Figure 10 7 shows the Debug Terminal displayed by PasswordChecker bs2 _ When run this program will wait for you to type the letters pass in response to the prompt V Enter and run PasswordChecker bs2 Try entering some letter combinations that are not the password then enter the letter combination that is the password pass 10 x m coe oe pa Bits Flow Control x DIRT ATS 2 RX DSR CTS Figure 10 7 abcdefghijpass Entering Password i a into the Transmit Windowpane Enter password abcde Password not correct Enter password fghij Password not correct Enter password pass Password is correct Click the Transmit upper Windowpane and enter the password bd wj Macros Pause Clear Close I Echo Off What s a Microcontroller PasswordChecker bs2 Check password entered in Debug Terminal s Transmit Windowpane SSTAMP BS2 G PBAS TERAS Password DATA pasent Store secret password here index VAR Nib Index variable temp VAR Byte Stores single char userEntry VAR Byte 5 Store user entered password DO DEBUG Enter password User instructions Page
51. UNTIL IN3 0 AND IN4 0 LOW 14 DEBUG Player A Time DEC timeCounterA DEBUG Player B Time DEC timeCounterB IF timeCounterA lt timeCounterB THEN DEBUG Player A is the winner CR ELSEIF timeCounterB lt timeCounterA THEN DEBUG Player B is the winner CR ELSE DEBUG It s a tie CR ENDIF DEBUG CR DEBUG To play again hold the CR DEBUG buttons down again CR CR LOOP increment counter Loop until both buttons released Bi color LED Ofte AES s AAEE S r A US T OR OR A amp B times are equal Play again instructions Back to Begin main Page 102 What s a Microcontroller Further Investigation The resources listed here are available for free download from the Parallax web site and are also included on the Parallax CD BASIC Stamp Manual Users Manual Version 2 0c Parallax Inc 2000 The BASIC Stamp Manual has more examples you can try and information that further explains the following The DEBUG HOME and cts formatters input pin variables such IN3 IN4 and the RANDOM command Basic Analog and Digital Student Guide Version 2 0 Parallax Inc 2003 Basic Analog and Digital explains binary counting using pushbuttons It also uses pushbuttons to introduce a technique for transmitting numbers from one system to another called synchronous serial communication BASIC Stamp Editor Help File PBASIC 2 5 Version 2 0 Parallax Inc 20
52. Unlike the potentiometer the photoresistor s resistance changes with light levels instead of with position Stamp Plot Lite was used to graph successive light measurements and methods for recording and interpreting graphical data were introduced The WRITE and READ commands were used to store and retrieve values to and from the BASIC Stamp module s EEPROM The EEPROM was then used in an RC time data logging application In this chapter s last activity a light meter application was developed This application used subroutines to perform the three different jobs required for the light meter to function Questions 1 What kind of different things can sensors detect 2 What is the name of the chemical compound that makes a photoresistor sensitive to light How is a photoresistor similar to a potentiometer How is it different What does EEPROM stand for 5 How many bytes can the BASIC Stamp module s EEPROM store How many bits can it store 6 What command do you use to store a value in EEPROM What command do you use to retrieve a value from EEPROM Which one requires a variable 7 What is a label 8 What is a subroutine 9 What command is used to call a subroutine What command is used to end a subroutine Ap Exercises 1 Draw the schematic of a photoresistor RC time circuit connected to P5 Modify TestPhotoresistor bs2 to so that it works on a circuit connected to P5 instead of P2 3 Explain how you would modify
53. a Microcontroller ServoControlWithPushbuttons bs2 Press and hold P4 pushbutton to rotate the servo counterclockwise or press the pushbutton connected to P3 to rotate the servo clockwise SSTAMP BS2 PBASIC 2 5 duration VAR Word duration 750 DO PR ENS E dL EHEN IF duration gt 500 THEN duration duration 25 ENDIF ENDIF Chapter 4 Controlling Motion Page 133 IF IN4 1 THEN IF duration lt 1000 THEN duration duration 25 ENDIF ENDIF PULSOUT 14 duration PAUSE 10 DEBUG HOME DEC4 duration duration LOOP Your Turn Software Stoppers Servos have a built in mechanical stopper that prevents them from turning too far If you try to send a command like PULSOUT 14 2000 the servo will not turn to a position that corresponds to a Duration argument of 2000 This is because servos have built in mechanical stoppers that limit the range of motion By gently turning the horn you can feel when the servo s internal gears run into this mechanical stopper You can modify the example program in this activity so that the BASIC Stamp limits the servo s motion to a range that is narrower than the limits imposed by the mechanical stoppers Save ServoControlWithPushbuttons bs2 under a new name Adjust the software limits imposed on the servo s motion so that they are 650 and 850 instead of 500 and 1000 Adjust the software imposed rate so that the duration variable is incremented or decremented by
54. a piezospeaker circuit to the sensor array you developed in this chapter and write a program to test it 2 Modify TerminalOperatedSensorArray bs2 so that it has a 5 menu item that makes the piezospeaker beep at 2 kHz for 1 5 seconds 3 While working on one of the activities and projects in this book you may have thought to yourself hey I could use this to build a gt gt insert your project here lt lt Use the material you have learned in this book to invent a gadget or gizmo of your own design Page 298 What s a Microcontroller Solutions Ql Q2 Q3 Q4 El E2 P1 P2 Whenever possible It is much easier to find isolate and prevent problems Two ReadPushbuttonState bs2 from Chapter 3 and ReadPotWithRcTime bs2 from Chapter 5 While the con directive assigns a name to a number and while the vAR directive assigns a name to RAM the PIN directive assigns a name to a BASIC Stamp I O pin This name can then be used in place of the I O pin number throughout the program PBASIC figures out whether you are using it as an output to send a high low signal or as an input variable to store the state sensed by the I O pin 1 or 0 END ends the program it doesn t run anymore By contrast EXIT just breaks out of the loop and then the program keeps on running a Build the piezospeaker circuit on the breadboard b Run TestPiezoWithFreqout bs2 from Chapter 8 to test the speaker c Integrate the piezosp
55. and pin map If you are trying to build the circuit from the schematic in Figure 6 Il 10 without relying on Figure 6 11 make sure to consult the 7 segment LED display s pin aw map Figure 6 2 page 166 Page 172 What s a Microcontroller 1kQ All P15 P14 D P13 D P12 P1 D Figure 6 10 P10 D BASIC Stamp Controlled 7 P9 D Segment LED P8 D Display E D C DP G F A B Schematic LED s PI FS FS FS FS TN TS TS common Vss Be careful with the resistors connected to P13 and P14 Look carefully at the resistors A connected to P13 and P14 in Figure 6 11 There is gap between these two resistors The gap is shown because pin 8 on the 7 segment LED display is left unconnected A resistor j w connects I O pin P13 to 7 segment LED display pin 9 Another resistor connects P14 to 7 segment LED display pin 7 Chapter 6 Digital Display Page 173 Epce TG EAB hh 25 Figure 6 11 Wiring Diagram for Figure 6 10 ZX 0d ld Zd d rd a d d d d d d PPA Use the segment letters above this diagram as a reference uA SSA AGN Parallel Device The 7 segment LED display is called a parallel device because you have to use more than one I O line at a time to send data high and low information to the device In the case of this
56. as needed and return to the BASIC Stamp Editor Try downloading a program once more If none of these solutions work you may go to www parallax com and follow the Support link Or email support parallax com or call Tech Support toll free at 1 888 99 STAMP Appendix F More about Electricity Page 319 Appendix F More about Electricity What s an Electron An electron is one of the three fundamental parts of an atom the other two are the proton and the neutron One or more protons and neutrons stick together in the center of the molecule in an area called the nucleus Electrons are very small in comparison to protons and neutrons and they orbit around the nucleus Electrons repel each other and electrons and protons attract to each other What s Charge The tendency for an electron to repel from another electron and attract to a nearby proton is called negative charge The tendency for a proton to repel from another proton and attract an electron is called positive charge When a molecule has more electrons than protons it is said to be negatively charged If a molecule has fewer electrons than protons it is said to be positively charged If a molecule has the same number of protons and electrons it is called neutrally charged What s Voltage Voltage is like electrical pressure When a negatively charged molecule is near a positively charged molecule the extra electron on the negatively charged molecule tries to get from
57. be connected to power for it to run It also needs to be connected to a PC so it can be programmed After making these connections you can use the BASIC Stamp Editor to test the system This activity will show you how Figure 1 21 InstallShield Wizard Completed Click the Finish button Introducing the BASIC Stamp Board of Education and HomeWork Board Parallax Inc s Board of Education carrier board shown in Figure 1 22 next to a BASIC Stamp module As mentioned earlier the BASIC Stamp is a type of very small computer This very small computer plugs into the Board of Education carrier board As you will soon see the Board of Education makes it easy to connect a power supply and serial cable to the BASIC Stamp module In later activities you will also see how the Board of Education makes it easy to build circuits and connect them to your BASIC Stamp module Figure 1 22 BASIC Stamp 2 Microcontroller Module left and Board of Education Carrier Board right Page 14 What s a Microcontroller Parallax Inc s BASIC Stamp HomeWork Board is shown in Figure 1 23 This board is like a Board of Education with the BASIC Stamp 2 module built in Its surface mounted components are visible to the left of the white breadboard area You can use either the Board of Education with a BASIC Stamp module or the BASIC Stamp HomeWork Board as your project platform for the activities in this text Figure 1 23 B
58. by the READ command Let s say that the variable eepromValueA and eepromValueB are Word variables and littleEE is a byte variable Here are some commands to retrieve the values you stored using the write command READ 7 littleEE READ 8 Word eepromValueA READ 10 Word eepromValueB Example Program ReadLightMeasurementsFromEeprom bs2 This example program demonstrates how to use the READ command to retrieve the light measurements that were stored in EEPROM by StoreLightMeasurementsInEeprom bs 2 y After StoreLightMeasurementsToEeprom bs2 has completed disconnect and reconnect the power supply to the BASIC Stamp module to prove that the data is not erased from the module s EEPROM when the power is disconnected Also close and re open the BASIC Stamp Editor V Leave the BASIC Stamp module s power disconnected until you are ready to run ReadLightMeasurementsFromEeprom bs2 otherwise it will start taking measurements again y Enter and run ReadLightMeasurementsFromEeprom bs2 Compare the table that is displayed by this program with the one displayed by StoreLightMeasurementsInEeprom bs2 and verify that the values are the same What s a Microcontroller ReadLightMeasurementsFromEeprom bs2 Read light measurements from EEPROM SSTAMP BS2 SPBASIC 2 5 time VAR Word Chapter 7 Measuring Light Page 203 eepromAddress VAR Byte DEBUG Retrieving measurements CR CR Measurement Welle CR eee ee ee
59. can also use DIRH 00000000 to change all the I O pins back to inputs Before I O pins become outputs Up until the I O pins are changed from input to output they just listen for signals and update the INH variable This is the variable that contains IN8 INQ up through IN15 These variables can be used the same way that IN3 and _IN4 were used for reading pushbuttons in Chapter 3 W All BASIC Stamp I O pins start out as inputs This is called a default You have to tell a BASIC Stamp I O pin to become an output before it starts sending a high or low signal Both the HIGH and LOW commands automatically change a BASIC Stamp I O pin s direction to output Placing a 1 in the DIRH variable also makes one of the I O pins an output Figure 6 13 shows how to use the ouTH variable to selectively send high and low signals to P8 through P15 A binary 1 is used to send a high signal and a binary 0 is used to send a low signal This example displays the number three on the 7 segment LED display 1 BAFG CDE OUTH 11010110 Page 178 What s a Microcontroller g S Figure 6 13 Using OUTH to ole Control the gt High Low Signals oy of P8 P15 en orON OO x lt ALAALA BAFG CDE OUTH 11010110 The display is turned so that the three on the display is upside d
60. color LED If voltage is applied across the LED circuit current will pass through it in one direction and it glows a particular color If the voltage polarity is reversed current travels through the circuit in the opposite direction and it glows a different color Questions 1 What is the name of this Greek letter Q and what measurement does Q refer to 2 Which resistor would allow more current through the circuit a 470 Q resistor or a 1000 Q resistor 3 How do you connect two wires using a breadboard Can you use a breadboard to connect four wires together Page 68 What s a Microcontroller 4 What do you always have to do before modifying a circuit that you built on a breadboard 5 How long would pause 10000 last 6 How would you cause the BASIC Stamp to do nothing for an entire minute 7 What are the different types of variables 8 Cana byte hold the value 500 9 What will the command HIGH 7 do Exercises 1 Draw the schematic of an LED circuit like the one you worked with in Activity 2 but connect the circuit to P13 instead of P14 Explain how you would modify LedOnOff bs2 on Page 48 so that it will make your LED circuit flash on and off four times per second 2 Explain how to modify LedOnOffTenTimes bs2 so that it makes the LED circuit flash on and off 5000 times before it stops Hint you will need to modify just two lines of code Project 1 Make a 10 second countdown using one yellow LED and one b
61. d 4 0 7 b 320 c 2e e e d e 2f 2e e 2d d d c d 2e 2c d 2e e e d e 2f g 2a a 9 g9 9 2f d 2c RTTTL File DATA TakeMeOut ToTheBallgame d 4 0 7 b 225 2c6 c a6 g6 e 6 29 6 2d6 p 2c6 Cc a6 96 e6 29 6 96 p p a6 g 6 a6 e6 f6 96 a6 p f6 2d6 p 2a6 a6 a6 b6 c d b6 a6 g6 Chapter 8 Frequency and Sound Page 257 Downloading RTTTL Files There are lots of RTTTL files available for download from various sites on the World Wide Web These files are contributed by ring tone enthusiasts many of whom are not music experts Some phone tones are pretty good others are barely recognizable If you want to download and play some more RTTTL files make sure to remove any spaces from between characters then insert the text file between quotes Page 258 What s a Microcontroller SUMMARY This chapter introduced techniques for making sounds and musical tones using the BASIC Stamp and a piezoelectric speaker The FREQoUT command can be used to send a piezoelectric speaker high low signals that cause it to make sound effects and or musical notes The FREQOUT command has arguments that control the I O Pin the signal is sent to the Duration of the tone the frequency of the tone Freq1 The optional Frreg2 argument can be used to mix tones Sound effects can be made by adjusting the frequency and duration of tones and the pauses between The value of the frequency can also be swept across a range
62. direction and state high low of I O pins P8 through P15 OUTH DIRH Vin Vss Vdd Il Il TETTI 00000000 11111111 Figure 6 12 Using DIRH and OUTH to set all I O Pins to Output Low Chapter 6 Digital Display Page 177 The first command OUTH 00000000 gets all the I O pins P8 through P15 ready to send the low signals If they all send low signals it will turn all the LEDs in the 7 segment LED display off If you wanted all the 1 O pins to send the high signal you could use OUTH 11111111 instead What does do The is used to tell the BASIC Stamp Editor that the number is a binary 4 number For example the binary number 00001100 is the same as the decimal number Ae j 12 As you will see in this activity binary numbers can make many programming tasks much easier The low signals will not actually be sent by the I O pins until you use the DIRH variable to change all the I O pins from input to output The command DIRH 11111111 sets all I O pins P8 through P15 to output As soon as this command is executed P8 through P15 all start sending the low signal This is because the command OUTH 00000000 was executed just before this DIRH command As soon as the DIRH command set all the I O pins to output they started sending their low signals You
63. e 1 Yes it s true 1 A 1 V Q One amp is one volt per ohm v Let s say you turned two LEDs on at the same time That means that inside the BASIC Stamp it is supplying the circuits as shown in Figure F 4 Have we exceeded the 20 mA limit Let s find out Remember that the simplified version of Kirchoff s Current Law says that the total current drawn from the supply equals the current supplied to all the circuits That means that I in Figure F 4 has to equal the total of the two currents being drawn Simply add the two current draws and yov ll get an answer of 14 5 mA You are still under the 20 mA limit so your circuit is a safe design Vdd z Figure F 4 Taht lyti Total Current I 7 23m4A 7 23m4A Supplied to I 14 5mA Two LED Circuits Page 326 What s a Microcontroller Your Turn Modifying the Circuit Repeat the exercise in Figure F 2 but use Vin Vss 9V The answer is Vz 74V Repeat the exercise in Figure F 3 but use a 1 kQ resistor Answer I 3 4 mA V Use Vr 7 4 V to do the exercise in Figure F 3 with a 1 KQ resistor Answer 1 7 4 mA y Repeat the exercise shown in Figure F 4 with one of the resistors at 470 Q and the other at 1 kQ Answer I 7 23 mA 3 4 mA 10 63 mA Appendix G RTTTL Format Summary Page 327 Appendix G RTTTL Format Summary This is a summary intended to help make sense out of RTTTL format The full RTTTL specification can be found published at v
64. eee Page 54 What s a Microcontroller V Run the program a second time and verify that the value of counter shown in the Debug Terminal accurately tracks how many times the LED blinked Hint instead of clicking Run a second time you can press and release the Reset button on your Board of Education or Home Work Board What s a Microcontroller LedOnOffTenTimes bs2 Turn an LED on and off Repeat 10 times SSTAMP BS2 S PBASIC 2 5 counter VAR Byte FOR counter 1 TO 10 DEBUG counter HIGH 14 PAUSE 500 LOW 14 PAUSE 500 NEXT DEBUG All done END How LedOnOffTenTimes bs2 Works This PBASIC statement counter VAR Byte tells the BASIC Stamp Editor that your program will use the word counter as a variable that can store a byte s worth of information Chapter 2 Lights On Lights Off Page 55 What s a Byte A byte is enough memory to store a number between 0 and 255 The BASIC Stamp has four different types of variables and each can store a different range of numbers Table 2 2 Variable Types and Values They Can Store A 9 Variable type Range of Values wy Bit 0 to 1 Nib 0 to 15 Byte 0 to 255 Word 0 to 65535 The question mark formatter before a variable in a DEBUG command tells the Debug Terminal to display the name of the variable and its value This is how the command DEBUG counter displays both the name and the value of the counter variable
65. for Pb1Pin Pb1Pin PIN 3 DEBUG CLS PbiPin Here is another example where the BASIC Stamp Editor knows to substitute the value of 9 because the PhotoPin PinName is used in a HIGH command and an RCTIME command PhotoPin PIN 9 HIGH PhotoPin RCTIME PhotoPin 1 time Example Program TerminalOperatedSensorArray bs2 Figure 10 6 shows the Debug Terminal displayed by TerminalOperatedSensorArray bs2 The main menu is shown on the left and an example of the display when 4 is selected is shown on the right Remember to use the upper Windowpane to send your menu selections to the BASIC Stamp Enter and run TerminalOperatedSensorArray bs2 y Click the Debug Terminal s upper Windowpane and type digits to make your menu selections V The measurement displayed is the one taken at the instant the menu selection is made and it is displayed for 1 5 seconds Keep this in mind when you press and hold the pushbuttons adjust the potentiometer and cast shade onto the photoresistor Chapter 10 Running the Whole Show Page 289 Figure 10 6 Using the Debug Terminal to Select from a Menu ZiT ol x 7 Debug Terminal 1316 Com Port Baud Rate Parity Com Port Baud Rate Parity fom io Ao E NC Ae Data Bits Flow Control x M DIRI RTS Data Bits Flow Control M DIRI RTS z J fo z erx ens ects 8 H for erx psn crs 1122234344 Pushbutton 1 Pushbutton 2 Potentiometer Photoresistor EE miee 4 Capture M
66. from the Notes DATA DO UNTIL noteLetter Q A READ command gets a character from the Notes DATA and stores it in the noteLetter variable The noteLetter variable is then used in a LOOKDOWN command to set the value of the offset variable Remember that offset stores a 1 if b is detected a 2 if B is detected a 3 if C is detected and so on This offset value is then used in a LOOKUP command to figure out what the value of the noteFreg variable should be If offset is 1 noteFreq will be 1865 if offset is 2 noteFreq will be 1976 if offset is 3 noteFreq is 2093 and so on READ Notes index noteLetter LOOKDOWN noteLetter A upm NBM Lk CL nq D e R pn g G a pn Q offset LOOKUP offset 1760 1865 1976 2093 2217 Chapter 8 Frequency and Sound Page 237 2349 2489 2637 2794 2960 3136 3322 0 0 Jj noteFreq The note s frequency has been determined but the duration still has to be figured out The READ command uses the value of index to place a value from the Durations DATA into noteDuration READ Durations index noteDuration Then noteDuration is set equal to the WholeNote constant divided by the noteDuration If note duration starts out as 4 from a READ command it becomes 2000 4 500 If noteDuration is 8 it becomes 1500 8 250 noteDuration WholeNote noteDuration Now that noteDuration and noteFreq are determined the FREQOUT command plays the no
67. have an optional STEP argument The STEP argument can be used to make the servo rotate faster For example you can use the STEP argument to add 8 to Page 126 What s a Microcontroller counter each time through the loop instead of 1 by modifying the ror statement like this FOR counter 500 TO 1000 STEP 8 You can also make the servo turn the opposite direction by counting down instead of counting up In PBASIC FOR NEXT loops will also count backwards if the startValue argument is larger than the EndValue argument Here is an example of how to make a FOR NEXT loop count from 1000 to 500 FOR counter 1000 TO 500 You can combine counting down with a sTEP argument to get the servo to rotate more quickly in the clockwise direction like this FOR counter 1000 TO 500 STEP 20 The trick to getting the servo to turn at different rates is to use these FoR NEXT loops to count up and down with different step sizes The next example program uses these techniques to make the servo s horn rotate back and forth at different rates Example Program ServoVelocities bs2 V Enter and run the program VAs the program runs watch how the value of counter changes in the Debug Terminal y Also watch how the servo behaves differently through the two different FOR NEXT loops Both the servo s direction and speed change What s a Microcontroller ServoVelocities bs2 Rotate the servo counterclockwise slowly then clockwise rapidly
68. in the Debug Terminal The FOR NEXT loop and all the commands inside it are shown below The statement FOR counter 1 to 10 tells the BASIC Stamp that it will have to set the counter variable to 1 then keep executing commands until it gets to the NExT statement When the BASIC Stamp gets to the NExT statement it jumps back to the For statement The For statement adds one to the value of counter Then it checks to see if counter is greater than ten yet If not it repeats the process When the value of counter finally reaches eleven the program skips the commands between the For and NEXT statements and moves on to the command that comes after the NEXT statement FOR counter 1 to 10 DEBUG counter CR HIGH 14 PAUSE 500 LOW 14 PAUSE 500 NEXT The command that comes after the NEXT statement is Page 56 What s a Microcontroller DEBUG All done This command is included just to show what the program does after ten times through the FOR NEXT loop It moves on to the command that comes after the NEXT statement Your Turn Other Ways to Count y Replace the statement FOR counter 1 to 10 with this FOR counter 1 to 20 in LedOnOffTenTimes bs2 and re run the program What did the program do differently and was this expected y Try a second modification to the For statement This time change it to FOR counter 20 to 120 STEP 10 How many times did the LED flash What values displayed in the Debug Terminal AC
69. into space Nobody won the competition but this rocket almost made it The BASIC Stamp controlled just about every aspect of the launch sequence Figure 1 7 High tech and Aerospace Microcontroller Examples Ecological data collection by EME Systems left undersea research by Harbor Branch Institute center and JP Aerospace test launch right From common household appliances all the way through scientific and aerospace applications the microcontroller basics you will need to get started on projects like these are introduced here By working through the activities in this book you will get to Chapter 1 Getting Started Page 5 experiment with and learn how to use a variety of building blocks found in all these high tech inventions You will build circuits for displays sensors and motion controllers You will learn how to connect these circuits to the BASIC Stamp 2 module and then write computer programs that make it control displays collect data from the sensors and control motion Along the way you will learn many important electronic and computer programming concepts and techniques By the time you re done you might find yourself well on the way to inventing a gizmo of your own design HARDWARE AND SOFTWARE Getting started with BASIC Stamp microcontroller modules is similar to getting started with a brand new PC or laptop The first things that most people have to do when they get a new PC or laptop is take it out
70. is at its quietest the variations in air pressure are canceling each other out called interference as What s Enter and run MixingTones bs2 Keep an eye on the Debug Terminal as the tones play and note the different effects that come from mixing the different tones a Microcontroller MixingTones bs2 Demonstrate some of the things that happen when you mix two tones STAMP ix U U BS2 PBASIC 2 5 DEBUG Frequency 2000 CR FREQOUT 9 4000 2000 DEBUG Frequency 3000 CR FREQOUT 9 4000 3000 DEBUG Frequency 2000 3000 CR FREQOUT 9 4000 2000 3000 DEBUG Frequency 2000 2001 CR Chapter 8 Frequency and Sound Page 227 FREQOUT 9 4000 2000 2001 DEBUG Frequency 2000 2002 CR FREQOUT 9 4000 2000 2002 DEBUG Frequency 2000 2003 CR FREQOUT 9 4000 2000 2003 DEBUG Frequency 2000 2005 CR FREQOUT 9 4000 2000 2005 DEBUG Frequency 2000 2010 CR FREQOUT 9 4000 2000 2010 DEBUG Done CR END Your Turn Condensing the Code MixingTones bs2 was written to demonstrate some interesting things that can happen when you mix two different frequencies using the FREQOUT command s optional Freq2 argument However it is extremely inefficient y Modify MixingTones bs2 so that it cycles through the Freg2 arguments ranging from 2001 to 2005 using a word variable and a loop ACTIVITY 3 MUSICAL NOTES AND SIMPLE SONGS
71. joys Clk PAUSE 1000 NEXT DIRH 00000000 END Your Turn Displaying 0 through F Again y Modify DisplayDigitsWithLookup bs2 so that it counts from 0 through F in hexadecimal Don t forget to update the For NExT loop s start and end values ACTIVITY 4 DISPLAYING THE POSITION OF A DIAL In Chapter 5 Activity 4 you used the potentiometer to control the position of a servo In this activity you will display the position of the potentiometer using the 7 segment LED display Dial and Display Parts 1 7 segment LED display 8 Resistors 1 kQ brown black red 1 Potentiometer 10 kQ 1 Resistor 220 Q red red brown 1 Capacitor 0 1 uF 7 Jumper wires Building the Dial and Display Circuits Figure 6 14 shows a schematic of the potentiometer circuit that should be added to the project Figure 6 15 shows a wiring diagram of the circuit from Figure 6 14 combined with the circuit from Figure 6 10 on Page 172 V Add the potentiometer circuit to the 7 segment LED display circuit as shown in Figure 6 15 Page 182 What s a Microcontroller P5 220 Q Pot 10 kQ 0 1 pF nc Programming the Dial and Displa There is a useful command called the LooxpDown and yes it is the reverse of the LOOKUP command While the Lookup command gives you a number based o
72. left side connecting the pushbutton to P3 while the 10 kQ resistor is on the right connecting the pushbutton circuit to Vss Vss Figure 3 7 shows what the BASIC Stamp sees when the button is pressed and when it s not pressed When the pushbutton is pressed the BASIC Stamp senses that Vdd is connected to P3 Inside the BASIC Stamp this causes it to place the number 1 in a part of its memory that stores information about its I O pins When the pushbutton is not pressed the BASIC Stamp cannot sense Vdd but it can sense Vss through the 10 kQ and 220 Q resistors This causes it to store the number 0 in that same memory location that stored a 1 when the pushbutton was pressed Chapter 3 Digital Input Pushbuttons Page 77 VIN vss a RES VDD 5V P15 P14 P13 P12 P11 P10 Figure 3 7 pe BASIC Stamp Reading i a Pushbutton When the pushbutton is pressed the BASIC Stamp reads a 1 Vad south w ge EVN above When the sng gs2 gys pushbutton is not 5 a sy Pressed the BASIC Ej P15 Stamp reads a 0
73. lfetauk B52 Directoy FistProgrambs2 Entered into S Stamp Editor v2 0 Beta What s a Microcontroller FirstProgram bs2 Editor a BASIC Stamp sends message to Debug Terminal hal STAMP BS2 7 PBASIC 2 5 Enter your first DATA bs2 a DTMFOUT bs2 FirstProgram bs2 FORNEXT bs2 x program into the BASIC Stamp Editor as shown here DEBUG Hello it s me your BASIC Stamp END V Save your work by clicking File and selecting Save as shown in Figure 1 37 Enter the name FirstProgram into the File name field near the bottom of the Save As window as shown in Figure 1 38 Click the Save button File Edit Directive Run Help Save in EA My Documents ha B al fai IEAA oon y Pictures troller message File name JFitstProgram l Save as type BASIC Stamp 2 files bs2 bd Cancel Figure 1 37 Saving the First Program Figure 1 38 Entering the File Name filename FirstProgram bs2 unless you tell it to save to a different filename by clicking File The next time you save the BASIC Stamp Editor will automatically save to the same 1 and selecting Save As instead of just Save y Click Run and select Run from the menu that appears by clicking it as shown in Figure 1 39 Chapter 1 Getting Started Page 23 ty BASIC Stamp C Program Files Parallax In File Edit Directive Run Help Dgan E iour 1 39 Check Syntax Ctrl
74. logic to show which player had the faster reaction time IF timeCounterA lt timeCounterB THEN Page 100 What s a Microcontroller DEBUG Player A is the winner CR ELSEIF timeCounterB lt timeCounterA THEN DEBUG Player B is the winner CR ELSE DEBUG It s a tie CR ENDIF The complete solution is shown below What s a Microcontroller Ch03Prj03_ TwoPlayerReactionTimer bs2 Test reaction time with a pushbutton and a bi color LED Add a second player with a second pushbutton Both players play at once using the same LED Quickest to release wins Pin P3 Player A Pushbutton Active High Pin P4 Player B Pushbutton Active High SSTAMP BS2 D PBASIC 2 5 timeCounterA VAR Word Time score of player A timeCounterB VAR Word Time score of player B DEBUG Press and hold pushbuttons CR Display reaction instructions to make light turn red CR CR When light turns green let CR NGO as abt ae you can CR CR DO Begin main loop DO Loop until both press Nothing LOOP UNTIL IN3 1 AND IN4 1 LOW 14 Bi color LED red HIGH 15 PAUSE 1000 Delay 1 second HIGH 14 Bi color LED green LOW 15 timeCounterA 0 1 ger tameCountercmtomzcKo timeCounterB 0 DO PAUSE 1 IF IN3 1 THEN Tf button is still down Chapter 3 Digital Input Pushbuttons Page 101 timeCounterA timeCounterA 1 ENDIF IF IN4 1 THEN timeCounterB timeCounterB 1 ENDIF LOOP
75. may represent a violation of Parallax copyrights legally punishable according to Federal copyright or intellectual property laws Any duplication of this documentation for commercial uses is expressly prohibited by Parallax Inc Duplication for educational use is permitted subject to the following Conditions of Duplication Parallax Inc grants the user a conditional right to download duplicate and distribute this text without Parallax s permission This right is based on the following conditions the text or any portion thereof may not be duplicated for commercial use it may be duplicated only for educational purposes when used solely in conjunction with Parallax products and the user may recover from the student only the cost of duplication This text is available in printed format from Parallax Inc Because we print the text in volume the consumer price is often less than typical retail duplication charges BASIC Stamp Stamps in Class Board of Education and SumoBot are registered trademarks of Parallax Inc HomeWork Board Boe Bot and Toddler are trademarks of Parallax Inc If you decide to use the words BASIC Stamp Stamps in Class Board of Education HomeWork Board Boe Bot or Toddler on your web page or in printed material you must state that BASIC Stamp is a registered trademark of Parallax Inc Stamps in Class is a registered trademark of Parallax Inc Board of Education is a registered trademark of Parallax Inc S
76. more pushbuttons The BASIC Stamp was programmed to make decisions based on the state s of the pushbutton s and this information was used to control LED s A reaction timer game was built using these concepts In addition to controlling LEDs the BASIC Stamp was programmed to poll a pushbutton and take time measurements Reading individual pushbutton circuits using the special I O variables built into the BASIC Stamp IN3 IN4 etc was introduced Making decisions based on these values using IF THEN ELSE statements IF ELSEIF ELSE statements and code blocks were also introduced For evaluating more than one condition the AND and oR operators were introduced Adding a condition to a DO LOOP using the UNTIL keyword was introduced along with nesting Do LooP code blocks Questions 1 What is the difference between sending and receiving HIGH and Low signals using the BASIC Stamp 2 What does normally open mean in regards to a pushbutton 3 What happens between the terminals of a normally open pushbutton when you press it 4 What is the value of In3 when a pushbutton connects it to Vdd What is the value of IN3 when a pushbutton connects it to Vss 5 What does the command DEBUG IN3 do 6 What kind of code blocks can be used for making decisions based on the value of one or more pushbuttons 7 What does the Home formatter do in the statement DEBUG HOME Exercises 1 Explain how to modify ReadPushbuttonState bs2 on
77. need Downloads Page DOWNLOADS BASIC Stamp Software A g STEE Stamp Software Documentation eas Software Description More Information Download BASIC Stamp Tokenizer BASIC Stamp Windows Editor version 2 0 Beta 1 6MB fa q Educational Curriculum Windows 95 98 ME NT4 0 2K KP Javelin Stamp BASIC Stamp Windows Editor version 2 0 Beta 1 2 65MB SX Keys and Chips Note Same as above but requires internet connection during a install V When the File Download window shown in Figure 1 10 appears select Save this program to disk V Click the OK button File Download x You have chosen to download a file from this location Editor_v2 0_Beta_1_6MB exe from www parallax com What would you like to do with this file Bun this program from its current location T aera Figure 1 10 File Download Window I Always ask before opening thie type of fle Cancel More info Figure 1 11 shows the Save As window that appears next You can use the Save in field to browse your computer s hard drives to find a convenient place to save the file After choosing where to save the file you are downloading click the Save Button Page 8 What s a Microcontroller 2x Save in oJ Desktop z e cr E My Documents My Computer My Network Places History G Desktop oN Figure 1 11 Save As Window Selecting a place to save the file My Documents My Computer AJ a File nam
78. of the box plug it in install and test some software and maybe even write some software of their own using a programming language If this is your first time using a BASIC Stamp module you will be doing all these same activities If you are in a class your hardware may already be all set up for you If this is the case your teacher may have other instructions If not this chapter will take you through all the steps of getting your new BASIC Stamp microcontroller up and running ACTIVITY 1 GETTING THE SOFTWARE The BASIC Stamp Editor version 2 0 or higher is the software you will use in most of the activities and projects in this text You will use this software to write programs that the BASIC Stamp module will run You can also use this software to display messages sent by the BASIC Stamp that help you understand what it senses The BASIC Stamp Editor is free software and the two easiest ways to get it are Download from the Internet Look for BASIC Stamp Windows Editor version 2 0 on the www parallax com Downloads BASIC Stamp Software page e included on the Parallax CD Follow the Software link on the Welcome page fo Make sure the date printed on the CD is May 2003 or newer py In a Hurry Get your copy of the BASIC Stamp Windows Editor version 2 0 or higher and install it on your PC or laptop Then skip to Activity 3 Setting Up the Hardware and Testing the System If you have questions along the wa
79. or numbers in various formats on the PC screen in order to follow program flow called debugging or as part of the functionality of the BASIC Stamp application Display oe Your Turn y Use the scrollbar to review the DEBUG command s write up Notice that it has lots of explanations and example programs you can try Click the Contents tab and find DEBUG there Click the Search tab and run a search for the word DEBUG Repeat this process for the END command L L L Getting and Using the BASIC Stamp Manual The BASIC Stamp Manual is available for free download from the Parallax web site and it s also included on the Parallax CD It can also be purchased as a printed book Downloading the BASIC Stamp Manual from the Parallax Web Site Using a web browser go to www parallax com Point at the Downloads menu to display the options Point at the Documentation link and click to select it On the BASIC Stamp Documentation page find The BASIC Stamp Users Manual Click the Download icon that looks like a file folder to the right of the description BASIC Stamp User s Manual Version 2 0 3 2 MB ea eee Chapter 1 Getting Started Page 29 Viewing the BASIC Stamp Manual on the Parallax CD Click the Documentation link Click the next to the BASIC Stamps folder Click the BASIC Stamp Manual book icon Click the View button 1 J aA d aAa aA y Figure 1 47 sh
80. page 77 so that it reads the pushbutton every second instead of every 4 second 2 Explain how to modify ReadPushbuttonState bs2 so that it reads a normally open pushbutton circuit with a pull up resistor connected to I O pin P6 Page 98 Project l What s a Microcontroller Modify ReactionTimer bs2 so that it is a two player game Add a second button wired to P4 for the second player Solutions Ql Q2 Q3 Q4 Q5 Q6 Q7 El F2 P1 Sending uses the BASIC Stamp I O pin as an output whereas receiving uses the TO pin as an input Normally open means the pushbutton s normal state not pressed forms an open circuit When pressed the gap between the terminals is bridged by a conductive metal Current can then flow through the pushbutton IN3 when pushbutton connects it to Vdd IN3 0 when pushbutton connects it to Vss DEBUG IN3 sends the value of IN3 to the Debug Terminal IF THEN ELSE and IF ELSEIF ELSE The HomE formatter sends the cursor to the top left position in the Debug Terminal The Do LOOP in the program repeats every 1 4 second because of the command PAUSE 250 To repeat every second change the PAUSE 250 250ms 0 25 s Y4 s to PAUSE 1000 1000ms s DO DEBUG IN3 PAUSE 1000 LOOP Replace IN3 with IN6 to read I O pin P6 The program only displays the pushbutton state and does not use the value to make decisions it does not matter whether the resistor i
81. pins would eventually bend and break from all the pressure that the pushbutton receives when people press it Figure 3 1 i Normally Open h 1 Sh 4 Pushbutton 2 3 s 3 Schematic symbol left and part drawing right The left side of Figure 3 2 shows how a normally open pushbutton looks when it s not pressed When the button is not pressed there is a gap between the 1 4 and 2 3 terminals This gap makes it so that the 1 4 terminal can not conduct current to the 2 3 terminal This is called an open circuit The name normally open means that the pushbutton s normal state not pressed forms an open circuit When the button is pressed the gap between the 1 4 and 2 3 terminals is bridged by a conductive metal This is called closed and current can flow through the pushbutton Figure 3 2 id ta Normally Open i h i Pushbutton 2 3 2 3 Not pressed left and pressed right Test Parts for the Pushbutton 1 LED pick a color 1 Resistor 470 Q yellow violet brown 1 Pushbutton normally open 1 Jumper wire Building the Pushbutton Test Circuit Figure 3 3 shows a circuit you can build to manually test the pushbutton Chapter 3 Digital Input Pushbuttons Page 73 Always disconnect power from your Board of Education or BASIC Stamp HomeWork Board before making any changes to your test circuit From here onward the instructions gt will no longer say Disconnect power between each circuit modific
82. problem but it s definitely not the only solution Before continuing take a moment to think about how you would design this reaction timer Reaction Timer Game Parts 1 LED bi color 1 Resistor 470 Q yellow violet brown 1 Pushbutton normally open 1 Resistor 10 kQ brown black orange 1 Resistor 220 Q red red brown 2 Jumper wires Building the Reaction Timer Circuit Figure 3 14 shows a schematic and wiring diagram for a circuit that can be used with the BASIC Stamp to make a reaction timer game y Build the circuit shown in Figure 3 14 V Run TestBiColorLED bs2 from Chapter 2 Activity 5 to test the bi color LED circuit and make sure your wiring is correct y If you re built the pushbutton circuit for this activity run ReadPushbuttonState bs2 from Activity 2 in this chapter to make sure your pushbutton is working properly Page 90 What s a Microcontroller P15 1 Z 4 2 P14 470 Q Figure 3 14 Vdd Reaction Timer Circuit oo P3 220 Q 10 kQ Vss Programming the Reaction Timer This next example program will leave the bi color LED off until the game player presses and holds the pushbutton When the pushbutton is held down the LED will turn red for a short period of time When it turns gree
83. right The bi color LED is really just two LEDs in one package Figure 2 17 shows how you can apply voltage in one direction and the LED will glow red By disconnecting the LED and plugging it back in reversed the LED will then glow green As with the other LEDs if you connect both terminals of the circuit to Vss the LED will not emit light Page 62 What s a Microcontroller Vdd Vdd 470 Q 470 Q 1 2 470 Q pM qe NR LED LED A Red 2 1 Green Vss Vss Vss Bi Color LED Circuit Parts 1 LED bi color 1 Resistor 470 Q yellow violet brown 1 Jumper wire Building and Testing the Bi Color LED Circuit Figure 2 18 shows the manual test for the bi color LED Ss Figure 2 17 Bi color LED and Applied Voltage Red left green center and no light right V Disconnect power from your Board of Education or HomeWork Board Disconnect power again Reconnect power lt a eee eee Disconnect power Build the circuit shown on the left side of Figure 2 18 Reconnect power and verify that the bi color LED is emitting red light Verify that the bi color LED is now emitting green light Modify your circuit so that it matches the right side of Figure 2 18 Chapter 2 Lights On Lights Off Page 63
84. s Duration argument based on whether or not a certain button is pressed This allows both position control and sweeping motions depending on how the program is constructed and how the pushbuttons are operated Questions 1 What are the four external parts on a servo What are they used for 2 Is an LED circuit required to make a servo work 3 What command controls the low time in the signal sent to a servo What command controls the high time 4 What programming element can you use to control the amount of time that a servo holds a particular position 5 How do you use the Debug Terminal to send messages to the BASIC Stamp What programming command is used to make the BASIC Stamp receive messages from the Debug Terminal 6 What type of code block can you write to limit the servo s range of motion Chapter 4 Controlling Motion Page 135 Exercises 1 Write a code block that sweeps the value of puLsout controlling a servo from a Duration of 700 to 800 then back to 700 in increments of a 1 b 4 2 Adda nested For NEXT loop to your answer to exercise 1b so that it delivers ten pulses before incrementing the PULSOUT Duration argument by 4 Project 1 Modify ServoControlWithDebug bs2 so that it monitors a kill switch If the kill switch P3 pushbutton is pressed Debug Terminal should not accept any commands It should display Press Start switch to start machinery When the start switch P4 pushbutton is presse
85. some practice However it was included in this text more for fun than for the coding concepts it employs If you examine the code briefly you might notice that you have already used all of the commands and operators in the program Here is a list of the elements in this application example that should by now be familiar e Comments to help explain your code Page 256 What s a Microcontroller e Constant and variable declarations e DATA declarations e READ commands e IF ELSE ENDIF blocks e DO LOOP both with and without WHILE and UNTIL e Subroutines with cosus labels and RETURN e FOR NEXT loops e LOOKUP and LOOKDOWN commands e The FREQOUT and PAUSE commands e SELECT CASE Your Turn Different Tunes y Try replacing the RTTTL File DATA directive in MicroMusicWithRTTTL bs2 with each of the five different music files below AAT Only one RTTTL File DATA directive at a time Make sure to replace not add your w new RTTTL File DATA directive V Run MicroMusicWithRTTTL bs2 to test each RTTTL file RTTTL File DATA TwinkleTwinkle d 4 0 7 b 120 c c g 9 a a 29g f f e e d d 2c 9 9 f f e e 2d 9 9 f f e e 2d c c g g a a 2g f f e e d d 1c 1G RTTTL File DATA FrereJacques d 4 0 7 b 125 c d e c c d e c e f 2g e f 2g 89g 8a 8g 8f e c 8g 8a 8g 8f e c c g6 t 2C5 C gG A0 RTTTL File DATA Beethovens5 d 8 0 7 b 125 g g g 2d p f f f 2q RTTTL File DATA ForHe sAJollyGoodFellow
86. tested you will then write a program that combines each subsystem into a working unit Figure 10 1 shows the circuit schematic for the system you will build and the master parts list is below Always remember whenever possible test each subsystem individually before trying to make them work together If you follow this rule your projects will go much more smoothly and your chances of success will be greatly improved The activities in this chapter will guide you through the process Sensor Array Parts List 4 Resistors 220 Q red red brown 2 Resistors 10 kQ brown black orange 2 Pushbuttons normally open 2 Capacitors 0 1 uF 1 Potentiometer 10 kQ 1 Photoresistor 5 Jumper wires Page 282 What s a Microcontroller P9 220 Q Ky 0 1 uF Vss P7 220 Q Ne Pot 10 kQ OLTE Figure 10 1 Sensor Array System Schematic Vss Vdd Vdd ACTIVITY 1 BUILDING AND TESTING EACH PUSHBUTTON CIRCUIT This activity begins with building and testing a single pushbutton circuit Once you have confirmed that the first pushbutton circuit is operating properly you can then move on to building and testing the second pushbutton circuit Chapter 10 Running the Whole Show Page 283 Pushbutton Circuit Parts 2 Pushbuttons normally open 2 Resistors 10 kQ brown black orange 2 Resistors 220 Q red red brown 2 Jumper wires Building the First Pushbutton Circuit Build the pushbutton
87. the knob clockwise the wiper gets closer to the A terminal and as you turn the knob counterclockwise the wiper gets closer to the B terminal A A Figure 5 4 10 kQ w Adjusting the A Fot Potentiometer s Wiper Ww z Terminal B Chapter 5 Measuring Rotation Page 141 ACTIVITY 1 BUILDING AND TESTING THE POTENTIOMETER CIRCUIT Placing different size resistors in series with an LED causes different amounts of current to flow through the circuit Large resistance in the LED circuit causes small amounts of current to flow through the circuit and the LED glows dimly Small resistances in the LED circuit causes more current to flow through the circuit and the LED glows more brightly By connecting the W and A terminals of the potentiometer in series with an LED circuit you can use it to adjust the resistance in the circuit This in turn adjusts the brightness of the LED In this activity you will use the potentiometer as a variable resistor and use it to change the brightness of the LED Dial Circuit Parts 1 Potentiometer 10 kQ 1 Resistor 220 Q red red brown 1 LED any color 1 Jumper wire Building the Potentiometer Test Circuit Figure 5 5 shows a circuit that can be used for adjusting the LED s brightness with a potentiometer y Build the circuit shown in Figure 5 5 o Tip Use a needle nose pliers to straighten the kinks out of the potentiometer s legs before _ 1 _ plugging the device int
88. the line across the point of the triangle Figure 2 4 LED Part Drawing and Schematic Symbol Part Drawing above and schematic symbol below The LED s part drawings in later gt i pictures will have a a next to the anode leg LED Chapter 2 Lights On Lights Off Page 41 When you start building your circuit make sure to check it against the schematic symbol and part drawing For the part drawing note that the LED s leads are different lengths The longer lead is connected to the LED s anode and the shorter lead is connected to its cathode Also if you look closely at the LED s plastic case it s mostly round but there is a small flat spot right near the shorter lead that that tells you it s the cathode This really comes in handy if the leads have been clipped to the same length LED Test Circuit Parts 1 LED Green 1 Resistor 470 Q yellow violet brown a Identifying the parts In addition to the part drawings in Figure 2 2 and Figure 2 4 you can e use the photo on the last page of the book to help identify the parts in the kit needed for this 4 and all other activities For more information on the parts in this photo see Appendix B Equipment and Parts Lists Building the LED Test Circuit You will build a circuit by plugging the LED and resistor leads into small holes called sockets on the prototyping area shown in Figure 2 5 This prototyping area has blac
89. the notes to the microcontroller in the phone then plays the notes whenever a call comes in These are called ringing tones or often just ringtones One of the most widely used way of composing recording and posting notes is one that features strings of text that describe each note in the song Here is an example of how the first few notes from Beethoven s 5 look in RTTTL format Beethoven5 d 8 o 7 b 125 g 2d p f ff2d This format for storing musical data is called RTTTL which stand for Ringing Tone Text Transfer Language The great thing about RTTTL files is that they are widely shared via the World Wide Web Many sites have RTTTL files available for free download There are also free software programs that can be used to compose and emulate these files as well as download them to your cell phone The RTTTL specification is also published on the World Wide Web Appendix G summarizes how an RTTTL file stores notes durations pauses tempo and dotted notes This activity introduces some PBASIC programming techniques that can be used to recognize different elements of text The ability to recognize different characters or groups of characters and take action based on what those characters contain is extremely useful In fact it s the key to converting RTTTL format ringtone like Beethoven5S above into music At the end of this activity there is an application program that you can use to play RTTTL format ringtones Page 246 Wha
90. the photoresistor is also about the same as the one used to read the potentiometer Even though the programming is the same light is very different from rotation or position The activities in this chapter focus on applications that use light instead of position to give the microcontroller information Along the way some PBASIC programming techniques will be introduced that will help you with long term data storage and with making your programs more manageable and readable ACTIVITY 1 BUILDING AND TESTING THE LIGHT METER In this activity you will build and test an RC time circuit that reads the value of a photoresistor The RC time measurement will give you an idea of the light levels sensed by the photoresistor s light collecting surface As with the potentiometer test the time values measured by the RCTIME command will be displayed in the Debug Terminal Light Detector Test Parts 1 Photoresistor 1 Resistor 220 Q red red brown 1 Capacitor 0 01 uF 1 Capacitor 0 1 UF 1 Jumper wire e Although there are two capacitors in the list of parts you will only use one capacitor in wy the circuit at any given time Building the RC Time Circuit with a Photoresistor Figure 7 2 shows a schematic of the RC time circuit you will use in this chapter and Figure 7 3 shows the wiring diagram This circuit is different from the potentiometer circuit from Chapter 5 Activity 3 in two ways First the I O pi
91. the type of materials used to manufacture the transistor and the way those materials are layered on the silicon The best way to get started thinking about a transistor is to imagine it as a valve that is used to control current Different transistors control how much current passes through by different means This transistor controls how much current passes into C collector and back out of E emitter It uses the amount of current allowed into the B base terminal to control the current passing from C through E With a very small amount of current allowed into B a current flow of about 416 times that amount flows through the transistor into C and out of E Figure 9 2 B 2N3904 Transistor moO 2N3904 The 2N3904 Part Datasheet As mentioned earlier semiconductor manufacturers publish documents called datasheets for the parts they make These datasheets contain _ information engineers use to design the part into a product To see an example of a part datasheet for the 2N3904 Go to www fairchildsemi com Enter 2N3904 into the Search field wy on Fairchild Semiconductor s home page and click Go One of the search results should be a link to the 2N3904 Product Folder Follow the link to the product folder then click Download this Datasheet link Most web browsers display the datasheet by opening it with Adobe Acrobat Reader Transistor Example Parts 1 Transistor 2N3904 2 Resistors 100 kQ brown black yel
92. these time measurements with the RCTIME command The I O pin must be set HIGH and then the capacitor in the RC time circuit must be allowed to charge by using PAUSE before the RCTIME command can be used PBASIC programming can be used to measure a resistive sensor such as a potentiometer and scale its value so that it is useful to another device such as a servo This involves performing mathematical operations on the measured RC discharge time which the RCTIME command stores in a variable This variable can be adjusted by adding a constant value to it which comes in handy for controlling a servo In the Projects section you Chapter 5 Measuring Rotation Page 161 may find yourself using multiplication and division as well The con directive can be used at the beginning of a program to substitute a name for a number As with naming variables naming constants is also called creating an alias After an alias is created the name can be used in place of the number throughout the program This can come in handy especially if you need to use the same number in 2 3 or even 100 different places in the program You can change the number in the con directive and all 2 3 or even 100 different instances of that number are automatically updated next time you run the program Questions l When you turn the dial or knob on a sound system what component are you most likely adjusting 2 In a typical potentiometer is the resistance between t
93. to show you the device s status Figure 3 10 Button and LED on a Computer Monitor The BASIC Stamp can be programmed to make decisions based on what it senses For example it can be programmed to decide to flash the LED on off ten times per second when the button is pressed Pushbutton and LED Circuit Parts 1 Pushbutton normally open 1 Resistor 10 kQ brown black orange 1 LED any color 1 Resistor 220 Q red red brown 1 Resistor 470 Q yellow violet brown 2 Jumper wires Building the Pushbutton and LED Circuits Figure 3 11 shows the pushbutton circuit used in the activity you just finished along with the LED circuit used in Chapter 2 Activity 2 Chapter 3 Digital Input Pushbuttons Page 81 V Build the circuit shown in Figure 3 11 P14 470 Q N LED Vss Vdd Figure 3 11 Pushbutton and LED Circuit oo P3 220 Q 10 kQ Vss Programming Pushbutton Control The BASIC Stamp can be programmed to make decisions using an IF THEN ELSE statement The example program you are about to run will flash the LED on and off when the pushbutton is pressed using an IF THEN ELSE statement Each time through the Do LooP the IF THEN ELSE statement checks the state of the pushbutton and decides whether or
94. when it is not pressed Capture Macros Pause Clear Close Enter the ReadPushbuttonState bs2 program into the BASIC Stamp Editor Run the program Verify that the Debug Terminal displays the value 0 when the pushbutton is not pressed Verify that the Debug Terminal displays the value 1 when the pushbutton is pressed and held L 2da d What s a Microcontroller ReadPushbuttonState bs2 Check and send pushbutton state to Debug Terminal every 1 4 second SSTAMP BS2 SPBASIC 2 5 DO DEBUG IN3 PAUSE 250 LOOP How ReadPushbuttonState bs2 Works The pDo LooP in the program repeats every 4 second because of the command PAUSE 250 Each time through the DO LOOP the command DEBUG IN3 sends the value of IN3 to the Debug Terminal The value of IN3 is the state that I O pin P3 senses at the instant the DEBUG command is executed Chapter 3 Digital Input Pushbuttons Page 79 Your Turn A Pushbutton with a Pull up Resistor The circuit you just finished working with has a resistor connected to Vss This resistor is called a pull down resistor because it pulls the voltage at P3 down to Vss 0 volts when the button is not pressed Figure 3 9 shows a pushbutton circuit that uses a pull up resistor This resistor pulls the voltage up to Vdd 5 volts when the button is not pressed The rules are now reversed When the button is not pressed IN3 stores the number 1 and when the button is pressed I
95. with the Boe Bot Student Workbook Version 2 0 Parallax Inc 2003 Robotics with the Boe Bot makes use of the same servo control principles you just learned with a twist servos can also be modified and used as rolling robot motors Using the BASIC Stamp Board of Education and Robotics with the Boe Bot kit this text starts with the basics of robot navigation then guides you through navigation with sensors It also introduces some more in depth topics such as solving problems with artificial intelligence and navigation using elementary control systems SumoBot Student Workbook Version 1 1 Parallax Inc 2002 Robot Sumo is a very exciting competition that is fun for observers and participants SumoBot is a guided tour through building testing and competing with your own autonomous Mini Sumo class SumoBot robot This textbook offers a condensed presentation of the Robotics with the Boe Bot text material applied towards the goal of winning a robotic sumo wrestling contest Chapter 5 Measuring Rotation Page 139 Chapter 5 Measuring Rotation ADJUSTING DIALS AND MONITORING MACHINES Many households have dials to control the lighting in a room Twist the dial one direction and the light gets brighter twist the dial in the other direction and the light gets dimmer Model trains use dials to control motor speed and direction Many machines have dials or cranks used to fine tune the position of cutting blades and guiding s
96. written as HIGH rcPin The second can be written as RCTIME rcPin 1 time If you change your circuit later all you have to do is change the value in your constant declaration and both the HIGH and RCTIME commands will be automatically updated Page 158 What s a Microcontroller Likewise if you have to recalibrate your scale factor or offset you can also just change the con directives at the beginning of the program M e Assigning an alias is what you do when you give a variable constant or I O pin a name al using VAR CON or PIN Example Program ControlServoWithPotUsingConstants bs2 This program makes use of aliases in place of almost all numbers y Enter and run ControlServoWithPotUsingConstants bs2 V Observe how the servo responds to the potentiometer and verify that it s the same as the previous example program ControlServoWithPot bs2 What s a Microcontroller ControlServoWithPotUsingConstants bs2 Read potentiometer in RC time circuit using RCTIME command Apply scale factor and offset then send value to servo SSTAMP BS2 PBASIC 2 5 scaleFactor CON 185 offset CON 500 rcPin CON 7 delay CON 10 servoPin CON 14 time VAR Word DO HIGH rcPin PAUSE delay RCTIME rcPin 1 time time time scaleFactor time time offset PULSOUT servoPin time DEBUG HOME DEC5 time LOOP Scale scaleFactor OimesSic ley CHEESE Send pulse to servo Display adjusted time value
97. 00 Q is written 2 kQ Milli is metric for 1 1000 and it is abbreviated with a lower case m If the BASIC Stamp supplies an LED circuit with 3 4 thousandths of an amp that s 3 4 milliamps or 3 4 mA A What s a mA Pronounced milliamp it s the notation for one one thousandth of an amp i The m in mA is the metric notation for milli which stands for 1 1000 The A in mA stands W for amps Put the two together and you have milliamps and it s very useful for describing the amount of current drawn by the BASIC Stamp and the circuits connected to it How much current is 7 23 mA It s the amount of current the LED shown on the right side of Figure F 3 conducts You can replace the 470 Q resistor with a 220 Q resistor and the circuit will conduct 15 5 mA and the LED will glow more brightly If you use a 1000 Q resistor the circuit will conduct 3 4 mA and the LED will glow less brightly A 2000 Q resistor will cause the LED to glow less brightly still and the current will be 1 7 mA Figure F 3 shows an example of how to calculate the current the circuit uses if the resistor is 470 Q Start with Ohm s Law You know the answers to V 3 4 V and R 470 Q Now all you have to do is solve for I the current Appendix F More about Electricity Page 325 V IxR 3 4V I1x470Q I 3 4V 470Q Figure F 3 3 4V 1X470Q I 0 00723 Current through the Resistor j I 0 007234 I 7 23 A 1000 I 7 23mA
98. 03 The PBASIC 2 5 Help File has information on the WHILE and UNTIL conditions used with DO LOOP and information on nesting and IF THEN ELSE code blocks which is new to PBASIC 2 5 You can find this information by clicking the book icon on your BASIC Stamp Editor task bar then selecting PBASIC Reference from the menu in the left sidebar window This will open the PBASIC Command Reference alphabetical listing in the main window Detailed information can be found by clicking on each command Chapter 4 Controlling Motion Page 103 Chapter 4 Controlling Motion MICROCONTROLLED MOTION Microcontrollers make sure things move to the right place all around you every day If you have an inkjet printer the print head that goes back and forth across the page as it prints is moved by a stepper motor that is controlled by a microcontroller The automatic grocery store doors that you walk through are controlled by microcontrollers and the automatic eject feature in your VCR or DVD player is also controlled by a microcontroller ON OFF SIGNALS AND MOTOR MOTION Just about all microcontrolled motors receive sequences of high and low signals similar to the ones you ve been sending to LEDs The difference is that the microcontroller has to send these signals at rates that are usually faster than the eye can detect The timing and number of separate high low signals differ from one motor to the next but they can all be controlled by microcontrol
99. 1 Pushbutton 1 Pushbutton 2 3 Potentiometer Photoresistor piezo Goese DEBUGIN DEC1 request request request RETURN Read_Pushbutton_1 DEBUG CTS RETN PAUSE DelayReader RETURN Read_Pushbutton_2 i Read_Pot Read _Photoresistor Beep_Speaker CRF CRT CRI ECRI CR CR Page 300 What s a Microcontroller DEBUG CLS IN4 PAUSE DelayReader RETURN Read_Pot HIGH 7 PAUSE DelayRc RCTIME 7 1 time DEBUG CLS DEC time bi PAUSE DelayReader RETURN Read_Photoresistor isHLGis PAUSE DelayRc RCTIME 9 1 time DEBUG CLS DEC time R PAUSE DelayReader RETURN Beep Speaker DEBUG CLS 2000 Hz Beep for 1 5 seconds CR FREQOUT SpkrPin 1500 2000 2000 Hz beep for 1 5 8 RETURN P3 If you have created an interesting application with your What s a Microcontroller Kit and you want to share it with other students and teachers consider joining our Stamps In Class Yahoo Group See the Web Site and Discussion Lists section right after the title page at the front of this book for details Further Investigation Please go back to the Preface and read the section titles The Stamps in Class Curriculum All of the books listed there are available for free download from www parallax com and are also on the Parallax CD They contain a wealth of knowledge and instructions for continuing your explorations into electronics programming robotics and engineering In
100. 10 instead of 25 Decide what differences you expect to see in the way the servo behaves when you press the pushbutton Run the program and compare the actual results with your expected results lt lt 2 a A ee Page 134 What s a Microcontroller SUMMARY This chapter introduced microcontrolled motion using a servo A servo is a device that moves to and holds a particular position based on electronic signals it receives These signals take the form of pulses that last anywhere between 1 and 2 ms and they have to be delivered every 20 ms for the servo to maintain its position A programmer can use the PULSOUT command to make the BASIC Stamp send these signals Since pulses have to be delivered every 20 ms for the servo to hold its position the PULSOUT and PAUSE commands are usually placed in some kind of loop Variables can be used to store the value used in the PULSOUT command s Duration argument This causes the servo s horn to rotate in steps In this chapter a variety of ways to get the values into the variables were presented The variable can receive the value from your Debug Terminal using the DEBUGIN command The value of the variable can pass through a sequence of values if the same variable is used as the index for a For NEXT loop This technique can be used to cause the servo to make sweeping motions IF THEN statements can be used to monitor pushbuttons and add or subtract from the variable used in the PULSOUT command
101. 15 P14 P13 P12 P11 P10 Figure 5 12 a Wiring Diagram for P7 Figure 5 11 P6 J a T im u P Hf YE i s oodd PO oO X2 Programming RC Time Measurements The BASIC Stamp program to measure the potentiometer s resistance will do essentially the same thing that you did by hand in Activity 2 The equivalent of pressing and holding the pushbutton is a HIGH command followed by a pausz The RCTIME command is the BASIC Stamp module s way of letting go of the pushbutton and polling until the capacitor s voltage gets low enough to pass the threshold voltage of INn7 1 4 V Example Program ReadPotWithRcTime bs2 y Enter and run ReadPotWithRcTime bs2 y Try rotating the potentiometer s input shaft while monitoring the value of the time variable using the Debug Terminal What s a Microcontroller ReadPotWithRcTime bs2 Read potentiometer in RC time circuit using RCTIME command SSTAMP BS2 EG PBAS TORAS time VAR Word DO HIGH 7 PAUSE 100 RCTIME 7 1 time DEBUG HOME time DEC5 time LOOP Page 152 What s a Microcontroller How ReadPotWithRcTime bs2 Works Here are the pseudo code steps the program goes through to take the RC time measurement e Declare the variable time to store a time measurement e Code block within DO LOOP o Set I O pin P7 to HIGH o Wait for 100 ms 20 ms to make sure the capacitor is charged up and 80 more ms to keep the Debug Terminal display steady o Execute the RCTI
102. 2 experiments including several that use 7 segment LED displays and other types of displays This text makes use of the INEX 1000 board which has many of the components you variety of experiments have used in this text built into it Chapter 7 Measuring Light Page 189 Chapter 7 Measuring Light DEVICES THAT CONTAIN LIGHT SENSORS You have already worked with two different kinds of sensors The pushbutton can be thought of as a simple pressure sensor and the potentiometer is a position rotation sensor There are many kinds of sensors built into appliances and machines that are not as obvious as a button or a knob Other common sensors measure things like temperature smoke vibration tilt and light Although each of these different kinds of sensors can be found in one or more devices that most people use on a daily basis light sensors are probably the most common One example of an every day device that contains a light sensor is probably your television If it can be controlled by a handheld remote it has a built in detector for a type of light called infrared that cannot be seen by the human eye The handheld remote uses infrared light to transmit information about the channel volume and other keys that you might press to control the TV Another common example is a digital camera A camera s light sensors help it adjust for various lighting conditions so that the picture looks clear regardless of whether it s a sunny or clo
103. 310 Boe Bot 3 Breadboard See Prototyping Area Byte 55 247 SCs Cadmium Sulfide 189 Capacitor 143 45 149 Ceramic 150 Polar identifying terminals 143 Page 330 What s a Microcontroller Carriage return 25 Cathode 40 Charge 319 Circuit 41 Collector 265 COM Port 15 196 Comment 24 Comment 52 Compiler directives 21 24 Components BASIC Stamp 307 BASIC Stamp HomeWork Board 309 Board of Education 308 Board of Education Rev B 310 Conductor 319 Counting 90 CR 25 Current 38 44 45 319 Flow 45 Milliamp 324 Cycle 219 D DATA 230 DEBUG Command 25 DEBUG Formatters CR 25 DEC 25 Debug Terminal 23 Receive Windowpane 120 121 Transmit Windowpane 120 121 DEBUGIN 120 23 292 DEBUGIN Formatters STR 292 DEC 25 120 Digital Potentiometer 267 77 Diode Forward Voltage 323 DIRH 175 78 Disconnect power 32 Dot Notes 238 Duration 222 229 231 233 38 JE Echo 120 121 EEPROM 197 203 230 263 Electron 45 319 Embedded system 1 Emitter 265 END 25 EXIT 292 F Fetch and Execute 263 Flat 228 FOR NEXT 53 56 114 FREQOUT 221 Frequency Duration 222 Mixing 222 225 27 Musical Notes 227 30 a ee GOSUB 206 Ground 323 Guarantee 3 H Hertz 219 HIGH 49 Hz See Hertz VO Pins See Input Output Pins IC See Integrated Circuit Identification Window 19 Identify 316 317 IF ELSEIF ELSE 85 IF TH
104. 48 How Many Times There are many ways to make the LED blink on and off ten times The simplest way is to use a FOR NEXT loop The FoR NEXxT loop is similar to the Do Loop Although either loop can be used to repeat commands a fixed number of times FOR NEXT is easier to use The FOR NEXT loop depends on a variable to track how many times the LED has blinked on and off A variable is a word of your choosing that is used to store a value The next example program uses the word counter to count how many times the LED has been turned on and off Picking words for variable names has several rules 1 The name cannot be a word that is already used by PBASIC These words are called reserved words and some examples that you should already be familiar with are DEBUG PAUSE HIGH LOW DO and LOOP ay 2 The name cannot contain a space 3 Even though the name can contain letters numbers or underscores it must begin with a character 4 The name must be less than 33 characters long Example Program LedOnOffTenTimes bs2 The program LedOnOffTenTimes bs2 demonstrates how to use a FOR NEXT loop to blink an LED on and off ten times Your test circuit from Activity 2 should be built or rebuilt and ready to use Enter the LedOnOffTenTimes bs2 code into the BASIC Stamp Editor Connect power to your Board of Education or HomeWork Board Run the program Verify that the LED flashes on and off ten times AE
105. 5 ms To play again hold the button down again 4 Capture Macros Pause Cea Close Echo Off Figure 3 15 Debug Terminal Reaction Timer Game Instructions Test reaction time with a pushbutton and a bi color LED STAMP BS2 PBASIC 2 5 meCounter VAR Word BUG Press and hold pushbutton CR to make light turn red CR CR When light turns green let CR go as fast as you can CR CR DO LOOP UNTIL LNS LOW 14 HIGH 15 PAUSE 1000 HIGH 14 LOW 15 timeCounter 0 Declare variable to store time Display reaction instructions Begin main loop Nested loop repeats until pushbutton press Bi color LED red Delay 1 second Bi color LED green Set timeCounter to zero Page 92 What s a Microcontroller DO Nested loop count time PAUSE 1 timeCounter timeCounter 1 LOOP UNTIL IN3 0 until pushbutton is released LOW 14 Bi color LED off DEBUG Your time was DEC timeCounter Display time measurement Mwy CORE MCI To play again hold the CR Play again instructions button down again CR CR LOOP Back to Begin main loop How ReactionTimer bs2 Works Since the program will have to keep track of the number of times the pushbutton was polled a variable called timeCounter is declared timeCounter VAR Word Declare variable to store time e Variables initialize to zero When a variable is declared in
106. 8 way it is shown in this H figure with the negative iy lead connected to Vss P3 P2 P1 PO x2 Polling the RC Time Circuit with the BASIC Stamp Although a stopwatch can be used to record how long it takes the capacitor s charge to drop to a certain level the BASIC Stamp can also be programmed to monitor the circuit and give you a more reliable time measurement Example Program PolledRcTimer bs2 Enter and run PolledRcTimer bs2 V Observe how the BASIC Stamp charges the capacitor and then measures the discharge time Page 146 What s a Microcontroller Record the measured time the capacitor s discharge time in the 470 Q row of Table 5 1 Disconnect power from your Board of Education or BASIC Stamp HomeWork Board Remove the 470 Q resistor labeled R in Figure 5 8 and Figure 5 9 on page 145 and replace it with the 1 KQ resistor Reconnect power to your board Record your next time measurement for the 1 KQ resistor Repeat these steps for each resistor value in Table 5 1 lt cee lt lt lt lt ra Table 5 1 Resistance and RC time for C 3300 uF Resistance Q Measured Time s 470 1k 2k 10k What s a Microcontroller PolledRcTimer bs2 Reaction timer program modified to track an RC time voltage decay SSTAMP BS2 PBASIC 2 5 timeCounter VAR Word counter VAR Nib DEBUG CLS
107. A SADPR KRKAKKAS Figure 1 42 Eef Detaut B52 Directory T FitstProgrambs2 FirstProgramYourTum bs2 Modified What s a Microcontroller FirstProgramYourTurn bs2 Fi P BASIC Stamp sends messages to Debug Terminal irst rogram STAMP BS2 PBASIC 2 5 Check your work fenegaos ce pe ean against the uals Belden DEBUG CR The answer is example FREQOUT bs2 DEBUG DEC 7 11 program shown here END Where did my Debug Terminal go Sometimes the Debug Terminal gets hidden behind the BASIC Stamp Editor window You can bring it back to the front by using the Run menu as shown at the left of Figure 1 43 the Debug Terminal 1 shortcut button shown at the right of the figure or the F12 key on your keyboard 9 Figure 1 43 aw Bun Help oe ce EZA AA dik cee Debug Terminal 1 to l Memoy Map Cult RIK MR Foreground E cof O lt Using the menu left Sete OH EE Debug Terminal 1 and using the shortcut button right Your Debug Terminal should now resemble Figure 1 44 Chapter 1 Getting Started Page 27 7 Debug Terminal 1 iol x i 2 Com Port Baud Rate Parity Data Bits Flow Control M DIRI RTS Figure 1 44 fore g fo dre l e dor a e ennac Modified Hello it s me your BASIC Stamp 4 FirstProgram bs2 inert Fi 112 Debug Terminal Output The answer is 77 Make sure that when you re run your program you get the
108. ASIC Stamp HomeWork Board Project Platform Education carrier boards and the HomeWork Board project platform See Appendix C Learn more about the features parts and functions of BASIC Stamp modules Board of BASIC Stamp and Carrier Board Components and Functions on page 307 Required Hardware 1 BASIC Stamp 2 module AND 1 Board of Education or 1 BASIC Stamp HomeWork Board 1 9 V battery 1 strip of 4 adhesive rubber feet 1 Serial cable cause Start with a new alkaline battery or a rechargeable battery that has recently been Start with a new or fully charged 9 V battery Avoid all the confusion a dead battery can fully recharged Chapter 1 Getting Started Page 15 O CAUTION Before using an AC adapter battery replacer or DC supply V Consult Appendix D Batteries and Power Supplies on page 311 to make sure the supply you use is appropriate for the activities in this text Connecting the Hardware Both the Board of Education and the BASIC Stamp HomeWork Board come with a strip that has four adhesive rubber feet These rubber feet are shown in Figure 1 24 and they should be affixed to the underside of your Board of Education or BASIC Stamp HomeWork Board Figure 1 24 Rubber Feet V Remove each rubber foot from the adhesive strip and affix it to the underside of your board as shown in Figure 1 25 If you are using the Board of Educatio
109. BASIC Stamp HomeWork Board y Connect the serial cable to the HomeWork Board Figure 1 29 step 1 y Connect a 9 V battery to the battery clip as shown in step 2 Page 18 What s a Microcontroller Figure 1 29 HomeWork Board and Serial Cable PARALAX Z OUa cy Plug the serial cable Mai Ve Nes and 9 V battery into the HomeWork Board 9 V Transistor Battery 9 V Transistor Battery Areyeg aulexiy TERIEN amp HomeWork Board Testing for Communication The BASIC Stamp Editor has a feature for testing to make sure your PC or laptop can communicate with your BASIC Stamp module V Double click the BASIC Stamp Editor shortcut on your desktop It should look similar to the one shown in Figure 1 30 Figure 1 30 BASIC Stamp Editor Shortcut 1 Look for a shortcut similar to BASIC Stamp this one on your computer s Editorv2 0 desktop Chapter 1 Getting Started Page 19 gt __ The Windows Start Menu can also be used to run the BASIC Stamp Editor Click your 1l Windows Start button then select Programs Parallax Inc BASIC Stamp Editor 2 then click the BASIC Stamp Editor icon Your BASIC Stamp Editor window should look similar to the one shown in Figure 1 31 hb list of your COM ports found by the software The first time you run your BASIC Stamp Editor it may display some messages and a
110. Board If you are connecting your servo to a Home Work Board you will need these extra parts 1 3 pin male male header shown in Figure 4 8 4 Jumper wires Figure 4 8 HomeWork Board or Board of Education Extra Parts 1 3 pin male male header top Figure 4 9 shows the schematic of the servo and LED circuits on the HomeWork Board The instructions that come after this figure will show you how to safely build this circuit WARNING Use only a 9 V battery when your Parallax Standard Servo is connected to the BASIC Stamp HomeWork Board Do not use any kind of DC supply or battery replacer that plugs into an AC outlet Improper use of these devices can cause the activity not to py work or even permanently damage the servo For best results make sure your battery is new If you are using a rechargeable battery make sure it is freshly recharged It should also be rated for 100 mAh milliamp hours or more See Appendix D Batteries and Power Supplies for more information Chapter 4 Controlling Motion Page 109 P14 470 Q Vin Figure 4 9 Schematic for Servo and LED Indicator on HomeWork Board V Disconnect your 9 V battery from your HomeWork Board y Build the LED indicator and servo header circuit shown in Figure 4 10 Page 110 What s a Microcontroller ae ae Figure 4 10 LED Indicator and Servo Header Circuits on HomeWork Board
111. CASE was introduced as a way of evaluating a variable on a case by case basis SELECT CASE is particularly useful for examining characters or numbers when there are many choices as to what the variable could be and many different sets of actions that Chapter 8 Frequency and Sound Page 259 need to be taken based on the variable s value A program that converts strings of characters that describe musical tones for cell phones called RTTTL files was used to introduce a larger program that makes use of all the programming techniques introduced in this text SELECT cASE played a prominent role in this program because it is used to examine characters selected in an RTTTL file on a case by case basis Questions l What causes a tone to sound high pitched What causes a tone to sound low pitched 2 What does FREQOUT 15 1000 3000 do What effect does each of the numbers have 3 How can you modify the FREQOUT command from Question 2 so that it sends two frequencies at once 4 Ifyou strike a piano s B6 key what frequency does it send 5 How do you modify a DATA directive or READ command if you want to store and retrieve word values 6 Can you have more than one DATA directive If so how would you tell a READ command to get data from one or the other DATA directive 7 What s an octave If you know the frequency of a note in one octave what do you have to do to that frequency to play it in the next higher octave 8 What does
112. CR Enter another value LOOP How SelectCaseWithValues bs2 Works A word variable is declared to hold the values entered into the Debug Terminal value VAR Word The DEBUGIN command takes the number you enter and places it into the value variable DEBUGIN DEC value The SELECT statement chooses the value variable as the one to evaluate cases for SELECT value The first case is if the value variable equals either 0 or 1 If value equals either of those numbers the DEBUG and PAUSE commands that follow it are executed CASE 0 1 DEBUG BIT CR PAUSE 100 The second case is if value equals any number from 2 to 15 If it does equal any of those numbers the DEBUG and PAUSE commands below it are executed CASE 2 to 15 DEBUG NIB Nibble CR PAUSE 200 When all the cases are done the ENDSELECT keyword is used to complete the SELECT CASE statement ENDSELECT Chapter 8 Frequency and Sound Page 249 Example Program SelectCaseWithCharacters bs2 This example program evaluates each character you enter into the Debug Terminal s Transmit Windowpane It can recognize upper and lower case characters digits and some punctuation If you enter a character the program does not recognize it will tell you to try again entering a different character y Enter and run SelectCaseWithCharacters bs2 y Click Debug Terminal s Transmit Windowpane enter characters and observe the results What s a Microcontroller SelectCas
113. Downloading the program and opening it with the BASIC Stamp Editor should save you a significant amount of time The alternative of course is to hand enter and debug four pages of code y Use the BASIC Stamp Editor to open your downloaded MicroMusicWithRtttl bs2 file or hand enter the example below very carefully V Run the program and verify that the piece is recognizable as the Reveille bugle call V Go to the Your Turn section and try some more tunes RTTTL_File DATA directives What s a Microcontroller MicroMusicWithRtttl bs2 Play Nokia RTTTL format ringtones using DATA SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running counter VAR Word General purpose counter char VAR Byte Variable stores characters index VAR Word Index for pointing at data noteLetter VAR Byte i PCM MONKS Claeueeveinsie noterreg VAR Word SUOMI MOIES IsersxewlSaveyy Page 252 What s a Microcontroller noteOctave VAR Word Stores note octave duration VAR Word Stores note duration tempo VAR Word Stores tempo default_d VAR Byte Stores default duration default_o VAR Byte Stores default octave default_b VAR Word Stores default beats min RTTTL File DATA Reveille d 4 0 7 b 140 8g6 8c 16e 16c 8g6 8e 8c 16e 16c 8g6 8e 8c 16e 16C 8a6 8C e 8C 8g96 taere r iee Bie IS IE Se Se eS Se Ie LoS 7 16c 8g6 8e C p 8e 8e 8e 8e gG 8e 8C 8e 8C 8e BC Ne Se Se Se Ne Se 8S ci Se SE Se H
114. E NelS e e Done DATA urls Notes DATA PA A a F kin A Wp i avast Tig Tiel Tee aR en Tew a Te 0 mEt Octave8 DATA Word 0O Word 3520 Word 3729 Word 3951 Word 4186 Word 4435 Word 4699 Word 4978 Word 5274 Word 5588 Word 5920 Word 6272 Word 6645 Initialization counter 0 Initialize counter GOSUB FindEquals T Gosliayel seataaisie VW aia miles GOSUB ProcessDuration Get default duration GOSUB FindEquals i jaaliael meee US GOSUB ProcessOctave L Cer Cloicewilic OCENE GOSUB FindEquals C mael lagg Tat GOSUB GetTempo Get default tempo Program Code DO UNTIL char qg Loop until q in DATA GOSUB ProcessDuration Get note duration GOSUB ProcessNote Get index value of note GOSUB CheckForDot PSE Oot Sy o Aurah ier GOSUB ProcessOctave Get octave GOSUB PlayNote 1 eap miser olay Tora Meres LOOP End of main loop END End of program Chapter 8 Frequency and Sound Page 253 FindEquals DO READ RTTTL File counter char counter counter 1 LOOP UNTIL char RETURN Go through characters in RTTTL file looking for ind Increment counter Wiajeslil TS alys see ysiayel eleven recur Subroutine Read Tempo from RTTTL Header Each keyboard character has a unique number called an ASCII value t Br sors S have ASCLE val eg of
115. EN ELSE 81 IN3 77 IN7 151 Indicator light 37 Input Output Pin Input 71 Input Output Pins 42 Default Direction 177 Integer 244 Integrated Circuit 264 Pin Map 268 Reference Notch 268 Interference 226 sde Jumper 106 aK kB 199 KB 199 KCL 323 Kilo 324 Kilobyte 199 Kirchoff s Laws Simplified Index Page 331 Current 323 Voltage 323 KVL 323 L Label 206 Light Emitting Diode 37 38 40 41 Anode 40 Bi Color 61 Cathode 40 Circuit Calculations 323 Schematic Symbol 40 Terminals 40 LOOKDOWN 182 LOOKUP 179 81 LOW 49 M mA 324 Math Operations 242 Memory Map 198 263 Menu 287 Metric units of measure 324 Microcontroller 1 Microsecond 114 Milli 324 Millisecond 49 114 Mixing 222 225 27 Multiply 94 Music Dot 238 Flat 228 FREQOUT and Notes 229 Natural 228 Page 332 What s a Microcontroller Note Duration 229 231 233 38 Notes 227 Piano Keyboard 227 Rest 233 Ringtone 245 RTTTL Format 327 28 RTTTL Format 245 251 57 Sharp 228 Tempo 233 N Natural 228 nc 167 Nested Loop 223 25 Neutral 45 Nib 55 247 No Connect 167 Notes 227 NPN 265 O Offset 155 Ohm 38 319 Ohm s Law 323 Omega 38 ON GOSUB 287 96 Operator 95 OUTH r 174 Overflow 247 P Parallax Standard Servo 103 Caution 104 154 Parts 104 Power Supply Caution 314 Parallel Bus 173 Device 173 Part Drawing 7 Seg
116. Eana Se EA CN ee results you expect ACTIVITY 5 LOOKING UP ANSWERS The two activities you just finished introduced two PBASIC commands DEBUG and END You can find out more about these commands and how they are used by looking them up either in the BASIC Stamp Editor s Help or in the BASIC Stamp Manual This activity guides you through an example of looking up DEBUG using the BASIC Stamp Editor s Help and the BASIC Stamp Manual Using the BASIC Stamp Editor s Help V In the BASIC Stamp Editor Click Help then select Index Figure 1 45 y BASIC Stamp File Edit Directive Run Help D S at A By __ Contents u te Default BS2 Directory B Parallax Inc WEEE to H E Javelin S visit Parallax Web Site ae Stamp E E mail Parallax Support Figure 1 45 Selecting Index from the Help Menu BRANCH bs2 BUTTON bs2 y Type DEBUG in the field labeled Type in the keyword to find Figure 1 46 V When the word DEBUG appears in the list below where you are typing click it then click the Display button Page 28 What s a Microcontroller PP poasic syntawcude Lo moo gr Hide Back Print Options Contents Index Search Type in the keyword to find DEBUG Figure 1 46 OCORA oo Faure Syntax DEBUG OutputData OutputData Sate Command Function Using Help Display information on the PC screen within the BASIC Stamp editor program This command can be used to display text
117. FREQOUT 9 500 1500 PAUSE 500 FREQOUT 9 500 1500 PAUSE 500 FREQOUT 9 500 1500 PAUSE 500 FREQOUT 9 500 1500 PAUSE 500 DEBUG Robot reply CCR PAUSE 100 FREQOUT 9 100 2800 Chapter 8 Frequency and Sound Page 225 FREQOUT 9 200 2400 FREQOUT 9 140 4200 FREQOUT 9 30 2000 PAUSE 500 DEBUG HYpEer space 2 4 Ck PAUSE 100 POR duration 15 TO 1 STEP 1 FOR frequency 2000 TO 2500 STEP 20 FREQOUT 9 duration frequency NEXT NEXT DEBUG Done CR END Your Turn More Sound Effects There is pretty much an endless number of ways to modify ActionTones bs2 to get different sound combinations Here is just one modification to the Hyperspace routine DEBUG Hyperspace jump CR FOR duration 15 TO 1 STEP 3 FOR frequency 2000 TO 2500 STEP 15 FREQOUT 9 duration frequency NEXT NEXT FOR duration 1 TO 36 STEP 3 FOR frequency 2500 TO 2000 STEP 15 FREQOUT 9 duration frequency NEXT NEXT y Save your example program under the name ActionTonesYourTurn bs2 y Have fun with this and other modifications of your Own invention Two Frequencies at Once You can send two frequencies at the same time In audio this is called mixing Remember the FREQOUT command s syntax from Activity 1 FREQOUT Pin Duration Freq1 Freq2 You can use the optional Freg2 argument to mix two frequencies using the FREQOUT command For example you can mix 2 and 3 kHz together like this FRE
118. IC Stamp module is not already plugged into your Board of Education insert it into the socket oriented as shown in Figure 1 28 step 1 Make sure the pins are lined up properly with the holes in the socket and not folded under then press down firmly y Plug the serial cable into the Board of Education as shown in step 2 Chapter 1 Getting Started Page 17 y Plug a DC power supply into the 6 9 VDC jack as shown in step 3 or plug a 9 V battery into the 9 VDC battery jack as shown in step 4 V Move the 3 position switch from position 0 to position 1 The green light labeled Pwr on the Board of Education should now be on a oa Figure 1 28 Z Board of Education Aieyeg BASIC Stamp JO SISUBL Piney Module Battery and 9VDC 15 14 Vdd 13 12 Serial Cable C m Tn Batte Red Bal ery 1 Black Connect 2 Vid Vin Ves components in Vs O FR g gg e order SE Alase peegel shown in the PRALAX E P12 O PRALA poBen engy Soooq jogogg diagram pooop jaoggo Make sure to aooo oona properly orient EEEE ERa Your BASIC ooooolL_jooooo Stamp module S0006 B6008 right side up Board of Education j i matching the 020023 notch on its top edge to notch on the socket aqqnacnnnnnnanj If you are using the
119. IME Scale pot match servo range increased pot turned CCW Bi color LED red value decreased pot turned CW Bi color LED green Servo holding position LED off The key is to add IF tHEN blocks an example is shown below What s a Microcontroller Ch5Prj02_ControlServoWithPot bs2 Read potentiometer in RC time circuit using RCTIME command The time variable ranges from 126 to 713 and an offset of 330 is needed Modify so the servo only rotates from 650 to 850 SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running time VAR Word DO HIGH 7 PAUSE 10 RCTIME 7 1 time time time 330 IF time lt 650 THEN time 650 ENDIF IF time gt 850 THEN time 850 ENDIF PULSOUT 14 time LOOP Read pot with RCTIME Scale time to servo range Constrain range from 650 to 850 Page 164 What s a Microcontroller Further Investigation Several different electronic components concepts and techniques were incorporated in this chapter Some of the more notable examples are e Using a potentiometer as an input device e Measuring the resistance capacitance of a device using RCTIME e Performing math on an input value and recycling it into an output e Controlling a motor based on a measured value Advanced Robotics with the Toddler Student Workbook Version 1 2 Parallax Inc 2003 Robotics with the Boe Bot Student Workbook Version 2 0 Parallax Inc 2003 SumoBot Stude
120. LED blink on and off one time per second It introduces several new programming techniques at once After running it you will experiment with different parts of the program to better understand how it works Example Program LedOnOff bs2 y Enter the LedOnOff bs2 code into the BASIC Stamp Editor y Reconnect power to your Board of Education or HomeWork Board V Run the program Verify that the LED flashes on and off once per second V Disconnect power when you are done with the program What s a Microcontroller LedOnOff bs2 Turn an LED on and off Repeat 1 time per second indefinitely SSTAMP BS2 SPBASIC 2 5 DEBUG The LED connected to Pin 14 is blinking Chapter 2 Lights On Lights Off Page 49 DO HIGH 14 PAUSE 500 LOW 14 PAUSE 500 LOOP How LedOnOff bs2 Works The command DEBUG The LED connected to Pin 14 is blinking makes this statement appear in the Debug Terminal The command HIGH 14 causes the BASIC Stamp to internally connect I O pin P14 to Vdd This turns the LED on The command Pause 500 causes the BASIC Stamp to do nothing for 2 a second while the LED stays on The number 500 tells the PAUSE command to wait for 500 1000 of a second The number that follows Pause is called an argument If you look up PAUSE in the BASIC Stamp Manual you will discover that it calls this number the Duration argument The name duration was chosen for this argument to show that the PAUSE command pauses for a c
121. ME command o Store the time measurement in the time variable o Display the value time in the Debug Terminal Before the RCTIME command is executed the capacitor is fully charged As soon as the RCTIME command executes the BASIC Stamp changes the I O pin from an output to an input As an input the I O pin looks about the same to the circuit as when the pushbutton was released open circuit in Activity 2 The RcTIME command is a high speed version of the polling that was used in Activity 2 and it measures the amount of time it takes for the capacitor to lose its charge and fall below the I O pin s 1 4 V input threshold Instead of counting in 100 ms increments the RCTIME command counts in 2 Us increments Your Turn Changing Time by Changing the Capacitor V Replace the 0 1 uF capacitor with a 0 01 uF capacitor y Try the same positions on the potentiometer that you did in the main activity and compare the value displayed in the Debug Terminal with the values obtained for the 0 1 UF capacitor Are the RCTIME measurements one tenth the value V Go back to the 0 1 uF capacitor y With the 0 1 uF capacitor back in the circuit and the 0 01 uF capacitor removed make a note of the highest and lowest values for the next activity ACTIVITY 4 CONTROLLING A SERVO WITH A POTENTIOMETER Potentiometers together with servos can be used to make lots of fun things This is the foundation for model airplanes cars and boats This activity shows
122. Meter Circuit Figure 7 9 shows the 7 segment LED display and photoresistor circuit schematics that will be used to make the light meter and Figure 7 10 shows a wiring diagram of the circuit The photoresistor circuit is the same one you have been using in the last two activities and the 7 segment LED display circuit is the one that was controlled by the BASIC Stamp in Chapter 6 Chapter 7 Measuring Light Page 205 1 kQ P15 D N A P14 O AW P13 D P12 D P1 D P10 DNW P9 D P8 D E D Cc DP G F A B LEDs Wy Wy Wy Wy Vy Vy Vy Yh Figure 7 9 Light Meter Circuit Schematic common Vss P2 220 Q hy 0 01 uF Page 206 What s a Microcontroller z x AN if Cicara lia lt Figure 7 10 7 Wiring Diagram opa for Figure 7 9 aces S e TEs o a V Build the circuit shown in Figure 7 9 and Figure 7 10 V Test the 7 segment LED display to make sure it is connected properly using SegmentTestWithHighLow bs2 from Chapter 6 Activity 2 Using Subroutines Most of the programs you have written so far operate inside a DO LOOP Since all the main activity happens inside the Do Loop it is usually called the main routine As you add more circuits and more useful functions to your program it can get kind of difficult to keep track of all the code in the main routine Your prog
123. N3 stores the number 0 nN The 220 Q resistor is used in the pushbutton example circuits to protect the BASIC Stamp WO pin Although it s a good practice for prototyping in most products this resistor is replaced with a wire since wires cost less than resistors V Modify your circuit as shown in Figure 3 9 y Re run ReadPushbuttonState bs2 y Using the Debug Terminal verify that IN3 is 1 when the button is not pressed and 0 when the button is pressed Vdd Vin Vss 3 Vdd ps t14 10 kQ bis P11 P3 w ooocgd oooog Figure 3 9 i Modified Pushbutton 220 Q P Circuit P6 P5 P4 P3 Pf ene Vss p POA oOg w8oooo a Active low vs Active high This pushbutton Figure 3 9 is called active low because it sends the BASIC Stamp a low signal Vss when the button is active pressed The wh pushbutton circuit in Figure 3 6 the main activity is active high because it sends a high signal Vdd when the button is active pressed Page 80 What s a Microcontroller ACTIVITY 3 PUSHBUTTON CONTROL OF AN LED CIRCUIT Figure 3 10 shows a zoomed in view of a pushbutton and LED used to adjust the settings on a computer monitor This is just one of many devices that have a pushbutton that you can press to adjust the device and an LED
124. Notes index noteLetter READ Frequencies index 2 Word noteFreq DEBUG noteLetter DEC noteFreq CR NEXT What does the index 2 do Each value stored in the Frequencies DATA directive takes a word two bytes while each character in the Notes DATA directive only takes yom one byte The value of index increases by one each time through the FOR NEXT loop That s fine for accessing the note characters using the command READ Notes ww index noteLetter The problem is that for every one byte in Notes the index variable needs to point twice as far down the Frequencies list The command READ Frequencies index 2 Word noteFregq takes care of this The next example program stores notes and durations using DATA and it uses the FREQOUT command to play each note frequency for a specific duration The result is the first few notes from the children s song Twinkle Twinkle Little Star e The Alphabet Song used by children to memorize their ABCs uses the same notes as 4 Twinkle Twinkle Little Star Example Program TwinkleTwinkle bs2 This example program demonstrates how to use the DATA directive to store lists and how to use the READ command to access the values in the lists V Enter and run TwinkleTwinkle bs2 Page 232 What s a Microcontroller Verify that the notes sound like the song Twinkle Twinkle Little Star Use the Debug Terminal to verify that it works as expected by acc
125. Off Control with the BASIC Stamp cececceeeeeeeeeeeeeeeeeeeeeeeeeetees 46 Activity 3 Counting and Repeating cccccccccceeeeceeeeeenceeeeeeeeeeeeseeeeeeseeeeeeeneeeetees 52 Activity 4 Building and Testing a Second LED Circuit ccceeeeeeeeeeeeeeteeeetees 56 Activity 5 Using Current Direction to Control a Bi Color LED c eceeeeeetees 60 SUTIN ANY eo ia oe Lt cE ee al cht aah eli aN cet SO i Mh eae Seo aah abel Oe 67 Chapter 3 Digital Input PUSHDUTCONS cseeeeeeeeee sete ee neeeeneeeeeeeeenseeeeeeeeeeeeeees 71 Found on Calculators Hand Held Games and Appliances ccssssecceeeeeesssteeeees 71 Receiving vs Sending High and Low Signals cccccccceeeeeeeeeeeeeeeeeeeeeeeeesneeeeeees 71 Activity 1 Testing a Pushbutton with an LED Circuit c cceeeeeeeeeeeeeeeeeeeeeeetees 71 Activity 2 Reading a Pushbutton with the BASIC Stamp c cceeeeceeeeeeteeetees 75 Activity 3 Pushbutton Control of an LED Circuit 0 cccceccecceceeeeeeeeeeeeeeeeeeeeeeeeees 80 Activity 4 Two Pushbuttons Controlling Two LED Circuits esceceeeeeeeeeeees 83 Activity 5 Reaction Timer Test ccccecccceeeeeceeeeeeceeeeeeeceeeeeeeeeeeeeneeeeeeseeeeesnneeeesees 88 SUMMAM iiai i eas deed ete ne Selvin ee Pantene ei a eid aie 97 Page ii What s a Microcontroller Chapter 4 Controlling Motion
126. P BS2 SPBASIC 2 5 DEBUG Tone sending CR FREQOUT 9 1500 2000 DEBUG Tone done Page 222 What s a Microcontroller Your Turn Adjusting Frequency and Duration Save TestPiezoWithFreqout bs2 under a different name Try some different values for the Duration and Freq1 argument After each change run the program and make a note of the effect As the Freq1 argument gets larger does the tone s pitch go up or down Try values of 1500 2000 2500 and 3000 to answer this question lt ce ee ACTIVITY 2 ACTION SOUNDS Many toys contain microcontrollers that are used to make action sounds Action sounds tend to involve rapidly changing the frequency played by the speaker You can also get some interesting effects from mixing two different tones together using the FREQOUT command s optional Freq2 argument This activity introduces both techniques Programming Action Sounds Action and appliance sounds have three different components 1 Pause 2 Duration 3 Frequency The pause is the time between tones and you can use the PAUSE command to create that pause The duration is the amount of time a tone lasts which you can set using the FREQOUT command s Duration argument The frequency determines the pitch of the tone The higher the frequency the higher the pitch the lower the frequency the lower the pitch This is of course determined by the FREQouT command s Freq1 argument Example Program Act
127. P2 changed to PS P5 220 Q ty 0 01 pF Vss The required changes are very similar to those explained on page 191 DO HIGH 5 PAUSE 100 RCTIME 5 1 time E3 P1 Chapter 7 Measuring Light Page 217 DEBUG HOME time DEC5 time LOOP To go in the opposite direction the patterns must be displayed in the reverse order This can be done by switching the patterns around inside the LOOKUP statement or by reversing the order they get looked up Solution 1 Update Display IF index 6 THEN index 0 d BAFG CDE LOOKUP index 01000000 10000000 00000100 00000010 00000001 7 00100000 OUTH index index 1 RETURN Solution 2 Update_Display 1 BAFG CDE LOOKUP index 01000000 10000000 00000100 00000010 00000001 00100000 OUTH IF index 0 THEN index 5 ELSE index index 1 ENDIF RETURN Photoresistor from Figure 7 2 p 191 LED from Figure 2 11 p 48 P2 214 0 01 pF 470 Q 2209 by Page 218 What s a Microcontroller The key to solving this problem is to insert an IF THEN statement that tests whether the photoresistor reading is above some threshold value If it is flash the LED The threshold value can be found by running TestPhotoresistor bs2 and observing the readings Note the difference between an unshaded and a shaded value Take a value somewhere in the middle and use that for your threshold In the solution shown the threshold value was en
128. PBASIC its value is WwW automatically zero until a command sets it to a new value The DEBUG commands contain instructions for the player of the game DEBUG Press and hold pushbutton CR to make light turn red CR CR When light turns green let CR go as fast as you can CR CR DO LOOP statements can be nested In other words you can put one DO LOOP inside another DO Begin main loop DO Nested loop repeats LOOP UNTIL IN3 1 until pushbutton press Rest of program was here LOOP Back to Begin main loop Chapter 3 Digital Input Pushbuttons Page 93 The inner Do Loop deserves a closer look A Do LOOP can use a condition to decide whether or not to break out of the loop and move on to more commands that come afterwards This Do LooP will repeat itself as long as the button is not pressed IN3 0 The Do L00P will execute over and over again until IN3 1 Then the program moves on to the next command after the LOOP UNTIL statement This is an example of polling The DO LOOP UNTIL polls until the pushbutton is pressed DO Nested loop repeats LOOP UNTIL IN3 1 until pushbutton press The commands that come immediately after the Loop UNTIL statement turn the bi color LED red delay for one second then turn it green LOW 14 Bi color LED red HIGH 15 PAUSE 1000 Delay 1 second HIGH 14 Bi color LED green LOW 15 As soon as the bi color LED turns green i
129. Prj01Soln2__KillSwitch bs2 Send messages to the BASIC Stamp to control a servo using the Debug Terminal as long as kill switch is not being pressed Contributed by Professor Clark J Radcliffe Department of Mechanical Engineering Michigan State University SSTAMP BS2 SPBASIC 2 5 counter VAR Word pulses VAR Word duration VAR Word DO PAUSE 2000 IF IN3 1 AND TNA 0 THEN DEBUG Press Start switch to start machinery Chek SR Wil ELSEIF IN3 0 AND IN4 1 THEN DEBUG CLS Enter number of pulses CR DEBUGIN DEC pulses DEBUG Enter PULSOUT duration CR DEBUGIN DEC duration DEBUG Servo is running CR FOR counter 1 TO pulses PULSOUT 14 duration PAUSE 20 NEXT DEBUG DONE PAUSE 2000 ENDIF LOOP Chapter 4 Controlling Motion Page 137 Further Investigation The servo and using sensors to control servos can be investigated in detail in a variety of Stamps in Class texts Advanced Robotics with the Toddler Student Guide Version 1 2 Parallax Inc 2003 Advanced Robotics with the Toddler uses servos to control the motions of the Parallax Toddler robot s legs Although we take walking for granted programming a machine to walk maneuver and keep its balance can be very challenging This walking robot is recommended for advanced students who have already mastered the concepts in What s a Microcontroller and either Robotics with the Boe Bot or SumoBot Robotics
130. QOUT 9 1000 2000 3000 Page 226 What s a Microcontroller Each touchtone keypad tone is also an example of two frequencies mixed together In telecommunications that is called DTMF Dual Tone Multi Frequency There is also a PBASIC command called DIMFOUT that is designed just for sending phone tones For examples of projects where phone numbers are dialed see the DIMFOUT command in the BASIC Stamp Manual Example Program MixingTones bs2 This example program demonstrates the difference in tone that you get when you mix 2 and 3 kHz together It also demonstrates an interesting phenomenon that occurs when you mix two sound waves that are very close in frequency When you mix 2000 Hz with 2001 Hz the tone will fade in and out once every second at a frequency of 1 Hz If you mix 2000 Hz with 2002 Hz it will fade in and out twice a second 2 Hz and so on Beat is when two tones very close in frequency are played together causing the tone you hear to fade in and out The frequency of that fading in and out is the difference between the two frequencies If the difference is 1 Hz the tone will fade in and out at 1 Hz If the difference is 2 Hz the tone will fade in and out at 2 Hz The variations in air pressure made by the piezoelectric speaker are called sound waves When the tone is loudest the variations in air pressure caused by the two frequencies are adding to each other called superposition When the tone
131. RETURN Pilisenelikc span Deliver pulses FOR counter oldTapSetting TO newTapSetting from old to new PULSOUT ClkPin 1 values PAUSE DelayPulses NEXT oldTapSetting newTapSetting Keep track of new and old RETURN tapSetting values Read_Photoresistor HIGH PhotoPin PAUSE 100 RCTIME PhotoPin 1 lightReading RETURN Further Investigation Industrial Control Student Guide Version 2 0 Parallax Inc 2002 Industrial Control uses the transistor as an on off switch for a resistor heating element spinning wheel It also uses a phototransistor to detect the passage of stripes on a Chapter 10 Running the Whole Show Page 281 Chapter 10 Running the Whole Show SUBSYSTEM INTEGRATION Most of the activities in this text introduce how to program the BASIC Stamp to interact with one or two circuits at a time Many microcontrollers have to handle tens or even hundreds of circuits This chapter will demonstrate a few of the techniques used to manage a variety of circuits with a single microcontroller Programming the microcontroller to orchestrate the activities of different circuits performing unique functions is called subsystem integration The example in this chapter uses a sensor array consisting of two pushbutton circuits a potentiometer circuit and a photoresistor circuit The activities in this chapter will guide you through building and testing each subsystem individually After each subsystem is built and
132. SE statement tells the SELECT code block what to do if none of the other cases are true You can get this case to work by entering a character such as or Your Turn Selecting Based on Ranges y Modify the SELECT cCASE statement in SelectCaseWithCharacters bs2 so that it displays Special character when you enter one of these characters ea amp ae pe or RTTTL Ringtone Player Application Program Below is the RTTTL file that contains the musical information used in the next example program There are five more RTTTL File DATA directives that you can try in the Your Chapter 8 Frequency and Sound Page 251 Turn section This program plays a tune called Reveille which is the bugle call played at military camps first thing in the morning You may have heard it in any number of movies or television shows RTTTL File DATA Reveille d 4 0 7 b 140 8g6 8c 16e 16c 8g6 8e 8c 16e 16c 8g6 8e 8c 16e 16c 8a6 8c e 8C 896 8c 16e 16c 8g6 8e 8c 16e 16c 8g6 8e 8c 16e 16c 8g6 8e C p 8e 8e 8e 8e g 8e 8C 8e 8C 8e 8C e 8c 8e 8e 8e 8e 8e 90 8e 8C 8e 8C 896 896 c Example Program MicroMusicWithRtttl bs2 This application program is pretty long and it s a good idea to download the latest version from the www parallax com Downloads Educational Curriculum page Look for a link named Selected Example Programs near the What s a Microcontroller PDF downloads
133. SELECT CASE do Exercises 1 Modify the Alarm tone from ActionTones bs2 so that the frequency of the tone it plays increases by 500 each time the tone repeats 2 Explain how to modify MusicWithMoreFeatures bs2 so that it displays an alert message in the Debug Terminal each time a dotted note is played Project l Build pushbutton controlled tone generator If one pushbutton is pressed the speaker should make a 2 kHz beep for 1 5 of a second If the other pushbutton is pressed the speaker should make a 3 kHz beep for 1 10 of a second Page 260 What s a Microcontroller Solutions Q1 Our ears detect changes in air pressure as tones A high pitched tone is from faster changes in air pressure a low pitched tone from slower changes in air pressure Q2 FREQOUT 15 1000 3000 sends a 3000 Hz signal out pin 15 for one second 1000 ms The effect of each number 15 pin number 15 1000 duration of tone equals 1000 ms or one second 3000 the frequency of the tone in Hertz so this sends a 3000 Hz tone Q3 Use the optional Freq2 argument To mix 3000 Hz and say 2000 Hz we simply add the second frequency to the command after a comma FREQOUT 15 1000 3000 2000 Q4 1975 5 Hz see Figure 8 3 on page 228 Q5 Use the optional wora modifier before each data item Q6 Yes Each pata directive has a different symbol parameter To specify which DATA directive to get the data from include the symbol parameter afte
134. Stamp will still take the time measurements for you using a command called RCTIME V Disconnect power to your Board of Education or HomeWork Board V Replace the 3300 uF capacitor with a 1000 uF capacitor Confirm that the polarity of your capacitor is correct The negative terminal should be connected to Vss V Reconnect power Chapter 5 Measuring Rotation Page 149 y Repeat the steps in the Example Program PolledRcTimer bs2 section and record your time measurements in Table 5 2 y Compare your time measurements to the ones you took earlier in Table 5 1 How close are they to 1 3 the value of the measurements taken with the 3300 uF capacitor Table 5 2 Resistance and RC time for C 1000 uF Resistance Q Measured Time s 470 1k 2k 10k ACTIVITY 3 READING THE DIAL WITH THE BASIC STAMP In Activity 1 a potentiometer was used as a variable resistor The resistance in the circuit varied depending on the position of the potentiometer s adjusting knob In Activity 2 an RC time circuit was used to measure different resistances In this activity you will build an RC time circuit to read the potentiometer and use the BASIC Stamp to take the time measurements The capacitor you use will be very small and the time measurements will only take a few milliseconds Even though the measurements take very short durations of time the BASIC Stamp will give you an excellent indication of the resistanc
135. T Running Your First tl Default BS2 Direc Memory Map Ctrl M Program i E St a G Debug gt Identify Ctrl I A Download Progress window will appear briefly as the program is transmitted from the PC or laptop to your BASIC Stamp module Figure 1 40 shows the Debug Terminal that should appear when the download is complete You can prove to yourself that this is a message from the BASIC Stamp by pressing and releasing the Reset button on your board Every time you press and release it the program will re run and you will see another copy of the message displayed in the Debug Terminal Press and release the Reset button Did you see a second Hello message appear in the Debug Terminal 9 Debug Terminal 1 Com Port Baud Rate Parity Coms z fe e nore z Data Bits Flow Control 1x M DIR I RTS e Heo ais DSR CTS Figure 1 40 Debug Terminal The Debug Terminal displays messages sent to the PC laptop by the BASIC Stamp module Capture Macros Pause Clear Close J Echo Off Page 24 What s a Microcontroller The BASIC Stamp Editor has shortcuts for most common tasks For example to run a program you can press the Ctrl and R keys at the same time You can also click the Run button It s the blue triangle shown in Figure 1 41 that looks like a CD player s Play button The flyover help the Run hint will appear if you point at the Run button with your mou
136. TIVITY 4 BUILDING AND TESTING A SECOND LED CIRCUIT Indicator LEDs can be used to tell the machine s user many things Many devices need two three or more LEDs to tell the user if the machine is ready or not if there is a malfunction if it s done with a task and so on In this activity you will repeat the LED circuit test in Activity 1 for a second LED circuit Then you will adjust the example program from Activity 2 to make sure the LED circuit is properly connected to the BASIC Stamp After that you will modify the example program from Activity 2 to make the LEDs operate in tandem Extra Parts In addition to the parts you used in Activities 1 and 2 you will need these parts 1 LED yellow 1 Resistor 470 Q yellow violet brown Chapter 2 Lights On Lights Off Page 57 Building and Testing the Second LED Circuit In Activity 1 you manually tested the first LED circuit to make sure it worked before connecting it to the BASIC Stamp Before connecting the second LED circuit to the BASIC Stamp it s important to test it too Disconnect power from your Board of Education or HomeWork Board V Construct the second LED circuit as shown in Figure 2 13 V Reconnect power to your Board of Education or HomeWork Board y Did the LED circuit you just added turn on If yes then continue If no Activity 1 h
137. The bi color LED schematic on the left is unchanged from Figure 2 20 on page 64 The yellow LED schematic is based on Figure 2 11 on page 48 For this project P14 was changed to P13 P15 P13 4 Red y A Green ee Yellow LED LED X LED 2 P14 4709 Vss What s a Microcontroller Ch02Prj01_ Countdown bs2 10 Second Countdown with Red Yellow Green LED Red Green Bicolor LED on P15 P14 Yellow P13 SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running counter VAR Byte Page 70 What s a Microcontroller Red for three seconds Bi color LED Red HIGH 15 LOW 14 PAUSE 3000 Green for 10 seconds LOW 15 HIGH 14 Bi color LED Green while the yellow LED is flashing FOR counter 1 TO 10 HIGH 13 Yellow LED on PAUSE 500 LOW 13 Yellow LED off PAUSE 500 NEXT Red stays on Bi Color LED Red HTCH ALS LOW 14 Further Investigation The resources listed here are available for free download from the Parallax web site and are also included on the Parallax CD BASIC Stamp Manual Users Manual Version 2 0c Parallax Inc 2000 The BASIC Stamp Manual has more examples you can try and information that further explains the following commands HIGH LOW PAUSE the DEBUG formatter and FOR NEXT Basic Analog and Digital Student Guide Version 2 0 Parallax Inc 2003 Basic Analog and Digital uses LEDs to describe counting in binary describes analog conditions and it introduce
138. The three commands inside that subroutine are executed When the program gets to the RETURN statement it jumps back to the command that comes right after the GosuB command which is DEBUG Back in Main CR What s a subroutine call When you use the GOSUB command to make the program jump C to a subroutine it is called a subroutine call Chapter 7 Measuring Light Page 209 PAUSE 2000 GOSUB First_Subroutine DEBUG Back in main CR Figure 7 12 First_Subroutine First Subroutine DEBUG Executing first Call DEBUG subroutine CR PAUSE 3000 RETURN Figure 7 13 shows a second example of the same process with the second subroutine call GOSUB Second Subroutine PAUSE 2000 GOSUB Second Subroutine DEBUG Repeat main CR i Figure 7 13 Second Subroutine Second Subroutine DEBUG Executing second Call DEBUG subroutine CR PAUSE 3000 RETURN Your Turn Adding and Nesting Subroutines You can add subroutines after the two that are in the program and call them from within the main routine y Add the subroutine example in the Figure 7 11 on page 207 to SimpleSubroutines bs2 Page 210 What s a Microcontroller V Make any necessary adjustments to the DEBUG commands so that the display looks right with all three subroutines You can also call one subroutine from within another This is called nesting subroutines y Try moving the cosus that calls Subroutine N
139. UGIN DEC duration After you enter the second value it s useful to display a message while the servo is running so that you don t try to enter a second value DEBUG Servo is running CR While the servo is running you can gently try to move the servo horn away from the position it is holding The servo resists light pressure applied to the horn FOR Counter StartValue TO EndValue STEP StepValue NEXT a This is the FOR NEXT loop syntax from the BASIC Stamp Manual It shows that you need 1 a Counter StartValue and EndValue to control how many times the loop repeats itself There is also an optional StepValue if you want to add a number other than 1 to the value of Counter each time through the loop Page 124 What s a Microcontroller As in previous examples the counter variable is used as an index for the FOR NEXT loop Up until this example all the For NExT loops have used constants such as 10 or 150 for Endvalue In this FoR NEXT loop the value of the pulses variable is used to control the Endvalue of the FoR NEXT loop This in turn controls how many pulses are delivered to the servo The end result is that the pulses variable controls how long the servo holds a given position Up until now constant values such as 500 750 and 1000 were also used for the PULSOUT command s Duration argument Look carefully at this FOR NEXT loop to see where and how these variables are used FOR counter 1 to pulses P
140. ULSOUT 14 duration PAUSE 20 NEXT Take some time to understand this FOR NEXT loop It is one of the first examples of the amazing things you can do with variables in PBASIC command arguments and it also highlights how useful a programmable microcontroller like the BASIC Stamp can be Your Turn Setting Limits in Software The example program doesn t stop you or anybody else from entering a PULSOUT duration such as 1500 which is not good for the servo This is a problem that needs to be fixed if you are designing this system into a product Let s imagine that this computer servo control system is one that has been developed for remote controlling a door Perhaps a security guard will use this to open a shipping door that he or she watches on a remote camera Maybe a college student will use it to control doors in a maze that mice navigate in search of food Maybe a military gunner will use it to point the cannon at a particular target If you are designing the product for somebody else to use the last thing you want is to give the user security guard college student military gunner the ability to enter the wrong number and damage the equipment To fix this problem try this y Save the example program ServoControlWithDebug bs2 under the new name ServoControlWithDebugY ourTurn bs2 V Replace these two commands DEBUG Enter pulsout duration CR DEBUGIN DEC duration Chapter 4 Controlling Motion Pa
141. What s a Microcontroller Student Guide VERSION 2 2 PAALLAX 7 WARRANTY Parallax Inc warrants its products against defects in materials and workmanship for a period of 90 days from receipt of product If you discover a defect Parallax Inc will at its option repair or replace the merchandise or refund the purchase price Before returning the product to Parallax call for a Return Merchandise Authorization RMA number Write the RMA number on the outside of the box used to return the merchandise to Parallax Please enclose the following along with the returned merchandise your name telephone number shipping address and a description of the problem Parallax will return your product or its replacement using the same shipping method used to ship the product to Parallax 14 DAY MONEY BACK GUARANTEE If within 14 days of having received your product you find that it does not suit your needs you may return it for a full refund Parallax Inc will refund the purchase price of the product excluding shipping handling costs This guarantee is void if the product has been altered or damaged See the Warranty section above for instructions on returning a product to Parallax COPYRIGHTS AND TRADEMARKS This documentation is copyright 2003 2004 by Parallax Inc By downloading or obtaining a printed copy of this documentation or software you agree that it is to be used exclusively with Parallax products Any other uses are not permitted and
142. Wizard for BASIC Stamp Editor v2 0 Beta 1 The InstallShield R Wizard will install BASIC Stamp Editor v2 0 Beta 1 on your computer To continue click Next Figure 1 18 InstallShield Wizard for the BASIC Stamp Editor WARNING This program is protected by copyright law and international treaties Click Next y Select Typical for your setup type as shown in Figure 1 19 Page 12 What s a Microcontroller Vv Click the Next button 0 Beta 1 InstallShield Wizard Setup Type Choose the setup type that best suits your needs Figure 1 19 Setup Type Click Typical then click the Next button When the InstallShield Wizard tells you it is Ready to Install the Program click the Jnstall button shown in Figure 1 20 i BASIC Stamp Editor v2 0 Beta 1 InstallShield Wizard Ready to Install the Prog The wizard is ready to begin installation Figure 1 20 Ready to Install Click the Install button V When the InstallShield Wizard window tells you InstallShield Wizard Completed as shown in Figure 1 21 click Finish Chapter 1 Getting Started Page 13 eS BASIC Stamp Editor v2 0 Beta 1 InstallShield Wizard aA A LER InstallShield Wizard Completed The InstallShield Wizard has successfully installed BASIC Stamp Editor v2 0 Beta 1 Click Finish to exit the wizard 7 Show the readme file ACTIVITY 3 SETTING UP THE HARDWARE AND TESTING THE SYSTEM The BASIC Stamp module needs to
143. a Sheets link Click the link that reads AD5220 Increment Decrement Digital Potentiometer Datasheet Digital Pot Controlled Transistor Parts 1 Transistor 2N3904 2 Resistors 100 kQ brown black yellow 1 LED any color 1 Digital potentiometer AD5220 Building the Digital Potentiometer Circuit Figure 9 6 shows a circuit schematic with the digital potentiometer used in place of a manual potentiometer and Figure 9 7 shows a wiring diagram for the circuit The BASIC Stamp can control the digital potentiometer by issuing control signals to P5 and P6 Build the circuit shown in Figure 9 6 and Figure 9 7 Vdd Vdd AD5220 Figure 9 6 Digital Potentiometer Controlled Transistor Circuit Schematic Page 270 What s a Microcontroller m4 P13 P12 P11 P10 P9 P8 P7 P6 b5 Figure 9 7 Digital Potentiometer Controlled Transistor Wiring Diagram P3 P2 P1 PO X2 Programming Digital Potentiometer Control Imagine that the knob on the manual potentiometer from the previous exercise has 128 positions Imagine also that the potentiometer is in the middle of its range of motion That means you could rotate the knob one direction by 63 steps and the other direction by 64 steps Le
144. a simple matter of connecting and disconnecting it from a power source In some cases the indicator light is connected directly to the battery or power supply like the power indicator light on the Board of Education Other indicator lights are switched on and off by a microcontroller inside the device These are usually status indicator lights that tell you what the device is up to MAKING A LIGHT EMITTING DIODE LED EMIT LIGHT Most of the indicator lights you see on devices are called light emitting diodes You will often see a light emitting diode referred to in books and circuit diagrams by the letters LED The name is usually pronounced as three letters L E D You can build an LED circuit and connect power to it and the LED emits light You can disconnect the power from an LED circuit and the LED stops emitting light Page 38 What s a Microcontroller An LED circuit can be connected to the BASIC Stamp and the BASIC Stamp can be programmed to connect and disconnect the LED circuit s power This is much easier than manually changing the circuit s wiring or connecting and disconnecting the battery The BASIC Stamp can also be programmed to do the following e Turn an LED circuit on and off at different rates e Turn an LED circuit on and off a certain number of times e Control more than one LED circuit e Control the color of a bi color two color LED circuit ACTIVITY 1 BUILDING AND TESTING THE LED CIRCUIT It s imp
145. aborate network that helped control and orchestrate the motion of each set of legs Robots like this not only help us better understand designs in nature but they may eventually be used to explore remote locations or even other planets ae A Rr f an M te T X pe th Figure 1 5 Examples of Research Robots that Contain Microcontrollers 2 Autonomous flying robot at UC Irvine left and Millipede Project at Nanyang University right Page 4 What s a Microcontroller With the help of microcontrollers robots will also take on day to day tasks such as mowing the lawn The BASIC Stamp module inside the robotic lawn mower shown in Figure 1 6 helps it stay inside the boundaries of the lawn and it also reads sensors that detect obstacles and controls the motors that make it move Figure 1 6 Robotic Lawn Mower Prototype by the Robot Shop Microcontrollers are also used in scientific high technology and aerospace projects The weather station shown on the left of Figure 1 7 is used to collect environmental data related to coral reef decay The BASIC Stamp module inside it gathers this data from a variety of sensors and stores it for later retrieval by scientists The submarine in the center is an undersea exploration vehicle and its thrusters cameras and lights are all controlled by BASIC Stamp microcontrollers The rocket shown on the right is one that was part of a competition to launch a privately owned rocket
146. acros Pause Clear Close I Echo Off What s a Microcontroller TerminalOperatedSensorArray bs2 Use Debug Terminal to choose to read one of four sensors SSTAMP BS2 0 PBASIC 2 5 Pb1Pin PIN Pb2Pin PIN PotPin PIN PhotoPin PIN Teese Constants DelayRc CON DelayReader CON Variables request VAR time VAR 3 4 Fi 9 ae ee Et eens a ere ey a Peat T en es ees ee eon ek ees neta oe Cte es ne E ee Pores E 100 1500 FR a a a Ta a ee E E I rT ET OL ON E eT OO I TR TN Re Nib Word GOSUB Display Menu GOSUB Get_Request ON request GOSUB Read_Pushbutton_1 Read_Pushbutton_2 Read_ Pot Read _Photoresistor Page 290 What s a Microcontroller Display Menu DEBUG CLS MENU T CR CR 1 Pushbutton 1 CR 2 Pushbutton 2 CR 3 Potentiometer CR 4 Photoresistor CR CR RETURN Get_Request DEBUGIN DEC1 request request request 1 RETURN ssse Sluloiemicdios Rec Pusidlowieweia I assssssssossssss esse ssa ssessssss Read_Pushbutton_1 DEBUG CLS PbiPin PAUSE DelayReader RETURN L Silerewiesias Rsc wislolowlieicei 2 e Read_Pushbutton_2 DEBUG CLS Pb2Pin PAUSE DelayReader RETURN c Siiloieilicwines RCl Bor sa sssssSes sss ses ses esses Ses eS see SSS Se sese Read_Pot HIGH PotPin PAUSE DelayRc RCTIME PotPin 1 time DEBUG CLS time i PAUSE DelayReader Chapter 10 Running the Whole Show Page 291
147. acters A through F you can further modify your program to count in hexadecimal from 0 to F Keeping Lists of On Off Patterns The LooKuP command makes writing code for 7 segment LED display patterns much easier The LOOKUP command lets you look up elements in a list Here is a code example that uses the LooKuP command LOOKUP index 7 85 19 167 28 value There are two variables used in this command index and value If the index is 0 value stores the 7 If index is 1 the value stores 85 Since index is 2 in this example the LOOKUP command places 19 into value and that s what the Debug Terminal displays Example Program SimpleLookup bs2 y Enter and run SimpleLookup bs2 V Run the program as is with the index variable set equal to 2 Try setting the index variable equal to numbers between 0 and 4 V Re run the program after each change to the index variable and note which value from the list gets placed in the value variable y Optional Modify the program by placing the Lookup command in a FOR NEXT loop that counts from 0 to 4 What s a Microcontroller SimpleLookup bs2 Debug a value using an index and a lookup table SSTAMP BS2 SPBASIC 2 5 value VAR Byte index VAR Nib index 2 DEBUG index LOOKUP index 7 85 19 167 28 value Page 180 What s a Microcontroller DEBUG value CR DEBUG Change the index variable to a CR different number between 0 and 4
148. always use the toolbar icons to place these compiler directives in your program to avoid typing errors Also entering the compiler directives by hand may not activate the syntax highlighting in the BASIC Stamp Editor That function is what causes various letters characters and words in your program to appear in different colors and capitalizations Syntax highlighting makes your programs easier to read understand and correct if there are any bugs in them Chapter 1 Getting Started Page 25 A command is a word you can use to tell the BASIC Stamp do a certain job The first of the two commands in this program is called the DEBUG command DEBUG Hello it s me your BASIC Stamp This is the command that tells the BASIC Stamp to send a message to the PC using the serial cable The second command is called the END command END This command is handy because it puts the BASIC Stamp into low power mode when it s done running the program In low power mode the BASIC Stamp waits for either the Reset button to be pressed and released or for a new program to be loaded into it by the BASIC Stamp Editor If the Reset button on your board is pressed the BASIC Stamp will re run the program you loaded into it If a new program is loaded into it the old one is erased and the new program begins to run Your Turn DEBUG Formatters and Control Characters A DEBUG formatter is a code word you can use to make the message the BASIC Stamp se
149. am that ask for input from the Debug Terminal were deleted including the Get_New_Tap_Setting subroutine What s a Microcontroller Ch9Prj0l_PhotoControlledDigitalPot bs2 Update digital pot s tap based on photoresistor reading STAMP BS2 PBASIC 2 5 DEBUG Program Running o Declarations and Initialization UdPin CON 5 Set values of I O pins ClkPin CON 6 connected to CLK and U D PhotoPin CON 2 Photoresistor on pin P2 DelayPulses CON 10 Delay to observe LED fade DelayReader CON 2000 Page 280 What s a Microcontroller counter VAR Byte Counter for FOR NEXT oldTapSetting VAR Byte Previous tap setting newTapSetting VAR Byte New tap setting lightReading VAR Word reading from photoresistor oldTapSetting 0 Initialize new and old newTapSetting 0 tap settings to zero LOW UdPin Set U D pin for Down FOR counter 0 TO 128 Set tap to lowest position PULSOUT 6 5 PAUSE 1 NEXT D oncs Medlin Routilas aSe eS ease eases SS SSS SSS eS SS SSS SS SS Se DO GOSUB Read_Photoresistor newTapSetting lightReading GOSUB Set_Ud Pin GOSUB Pulse Clk pin LOOP 0 eee EE Subroutines Set _Ud_ Pin IF newTapSetting gt oldTapSetting THEN r ELSEIF newTapSetting lt oldTapSetting THEN u Set U D pin for up down Deliver pulses Examine old and new tap values to decide value of UdPin Notify LOW UdPin user if values are ENDIF equal
150. am you will write and test will tell the BASIC Stamp to send a message to your PC or laptop Figure 1 33 shows how it sends a stream of ones and zeros to communicate the text characters displayed by the PC or laptop These ones and zeros are called binary numbers The BASIC Stamp Editor software has the ability to detect and display these messages as you will soon see F Figure 1 33 ABCDE Messages from the ABT OOOO COT BASIC Stamp module N oN to your Computer fo q o gt The BASIC Stamp a module sends Ry Koneg characters to your PC oy Spi B or laptop by aa fim transmitting a stream 0 01 0008 of binary ones and gt amp Pi zeros The BASIC i PEAR Stamp Editor can z A eae Fi detect and convert lt O Fa m these binary codes to 2 P B m gpi characters and display mB E i them P7 D Ups First Program The program listings that you will type into the BASIC Stamp Editor and download to the BASIC Stamp module will always be shown with a gray background like this Example Program FirstProgram bs2 What s a Microcontroller FirstProgram bs2 BASIC Stamp sends message to Debug Terminal SSTAMP BS2 SPBASIC 2 5 DEBUG Hello it s me your BASIC Stamp END Chapter 1 Getting Started Page 21 You will enter this program into the BASIC Stamp Editor Some lines of the program are made automatically by clicking buttons on the tool
151. ame into one of the other subroutines and see how it works e When nesting subroutines the rule is no more than four deep See the BASIC Stamp Manual for more details Look up GOSUB and RETURN Light Meter Using Subroutines The segments on the display cycle in a circular pattern that gets faster when the light on the photoresistor gets brighter When the light gets dimmer the circular pattern displayed by the 7 segment LED display goes slower The program that runs the light meter will deal with three different operations 1 Read the photoresistor 2 Calculate how long to wait before updating the 7 segment LED display 3 Update the 7 segment LED display Each operation is contained within its own subroutine and the main Do LooP routine will cycle and call each one in sequence over and over again Example Program LightMeter bs2 A Controlled lighting conditions make a big difference For best results conduct this test in a room lit by fluorescent lights with no direct sunlight close the blinds For information on wy how to calibrate this meter to other lighting conditions see the Your Turn section Enter and run LightMeter bs2 Verify that the circular pattern displayed by the 7 segment LED display is controlled by the lighting conditions the photoresistor is sensing Do this by casting a shadow over it with your hand or a piece of paper L 2 What s a Microcontroller LightMeter b
152. and Figure 6 9 show the digit 3 hardwired into the 7 segment LED display Page 170 What s a Microcontroller Vdd Vdd Vdd Vdd Vdd 1 KQ all Figure 6 8 Hardwired Digit 3 The digit 3 is shown on the 7 segment LED display using the circuit shown in this schematic fe nc Figure 6 9 Wiring Diagram for Figure 6 8 Build and test the circuit shown in Figure 6 8 and Figure 6 9 and verify that it displays the number three Draw a schematic that will display the number two on the 7 segment LED Build and test the circuit to make sure it works Trouble shoot if necessary Repeat for the letter A L Ll L a Chapter 6 Digital Display Page 171 ACTIVITY 2 CONTROLLING THE 7 SEGMENT LED DISPLAY In this activity you will connect the 7 segment LED display to the BASIC Stamp and then run a simple program to test and make sure each LED is properly connected 7 Seqment LED Display Parts 1 7 segment LED display 8 Resistors 1 kQ brown black red 5 Jumper wires Connecting the 7 Seqment LED Display to the BASIC Stamp Figure 6 10 shows the schematic and Figure 6 11 shows the wiring diagram for this BASIC Stamp controlled 7 segment LED display example V Build the circuit shown in Figure 6 10 and Figure 6 11 AN Schematic
153. ands The IF statement above has a code block with three commands HIGH HIGH and PAUSE The ELSEIF statement has a code block with two commands HIGH PAUSE V Run your modified program and see if it handles both pushbutton and LED circuits as you would expect N The AND keyword can be used in an IF THEN statement to check if more than one 1 condition is true All conditions with AND have to be true for the IF statement to be true The OR keyword can also be used to check if at least one of the conditions are true You can also modify the program so that the LED that s flashing stays on for different amounts of time For example you can reduce the Duration of the pause for both pushbuttons to 10 increase the Pause for the P14 LED to 100 and increase the PAUSE for the P15 LED to 200 y Modify the PAUSE commands in the IF and the two ELSEIF statements as discussed V Run the modified program V Observe the difference in the behavior of each light ACTIVITY 5 REACTION TIMER TEST You are the embedded systems engineer at a video game company The marketing department recommends that a circuit to test the player s reaction time be added to the Chapter 3 Digital Input Pushbuttons Page 89 next hand held game controller Your next task is to develop a proof of concept for the reaction timer test The solution you will build and test in this activity is an example of how to solve this
154. any of the Board of Education Revisions use a DC supply also called an AC adapter with the following ratings Input This depends on which country you live in and the amplitude and frequency of the AC power at the wall outlets For the USA and Canada the input should be 120 VAC 60 Hz Output 6 VDC 800 mA The mA rating can be higher A 6 V 1000 mA supply would be acceptable for example Plug The Board of Education has both a barrel jack which can be connected to a barrel plug and a 9 V battery connector which can be connected to a 9 V battery extension The HomeWork Board has only the 9 V battery connector Barrel Plug Figure D 1 shows DC supply commonly used with the BASIC Stamp and Board of Education It has a 2 1 mm center positive barrel plug along with the center positive symbol that is evident on its label Appendix D Batteries and Power Supplies Page 313 Figure D 1 DC Supply with Barrel Plug and Center Positive Symbol O e 9 V Battery Extension Figure D 2 shows an AC adapter connected to a 9 V battery extension that can be used with the BASIC Stamp HomeWork Board See WARNING discussed next Figure D 2 AC Adapter with 9 V Battery Extension Page 314 What s a Microcontroller WARNING Beware of Universal AC Adapters and Reversed Supply Terminals Figure D 3 shows a common mistake that should be avoided with universal adapters Many of these allow you to reverse the terminals on the
155. apter A capacitor can be used to store and release charge The amount of charge a capacitor can store is related to its value which is measured in Farads F The u is engineering notation for micro and it means one millionth The capacitors used in this chapter s activities ranged from 0 01 to 3300 UF A resistor and a capacitor can be connected together in a circuit that takes a certain amount of time to charge and discharge This circuit is commonly referred to as an RC time circuit The R and C in RC time stand for resistor and capacitor When one value C in this chapter s activities is held constant the change in the time it takes for the circuit to discharge is related to the value of R When the value of R changes the value of the time it takes for the circuit to charge and discharge also changes The overall time it takes the RC time circuit to discharge can be scaled by using a capacitor of a different size Polling was used to monitor the discharge time of a capacitor in an RC circuit where the value of C was very large Several different resistors were used to show how the discharge time changes as the value of the resistor in the circuit changes The RCTIME command was then used to monitor a potentiometer a variable resistor in an RC time circuit with smaller value capacitors Although these capacitors cause the discharge times to range from roughly 2 to 1500 us millionths of a second the BASIC Stamp has no problem tracking
156. apter introduced the 7 segment LED display and how to read a pin map This chapter also introduced some techniques for devices and circuits that have parallel inputs The DIRH and ouTH variables were introduced as a means of controlling the values of BASIC Stamp I O pins P8 through P15 The Looxup and LOOKDOWN commands were introduced as a means for referencing the lists of values used to display letters and numbers Questions l In a 7 segment LED display what is the active ingredient that makes the display readable when a microcontroller sends a high or low signal 2 What does common cathode mean What do you think common anode means 3 What is the group of wires that conduct signals to and from a parallel device called 4 What are the names of the commands in this chapter that are used to handle lists of values Exercises 1 Write an ouTH command to set P8 P10 P12 high and P9 P11 P13 low Assuming all your I O pins started as inputs write the DIRH command that will cause the I O pins to send high low signals while leaving P14 P15 configured as inputs 2 Write the values of ouTH required to make the letters a C d F H I n P S Project 1 Spell FISH CHIPS And dIP over and over again with your 7 segment LED display Make each letter last for 400 ms Solutions Q1 The active ingredient is an LED Q2 Common cathode means that all the cathodes are connected together i e they share a common connection point Com
157. ard newTapSetting by one This keeps the FOR NEXT loop from executing one too many times FOR counter oldTapSetting TO newTapSetting PULSOUT ClkPin 1 PAUSE DelayPulses NEXT oldTapSetting newTapSetting RETURN Chapter 9 Electronic Building Blocks Page 277 Keep track of new and old tapSetting values Page 278 What s a Microcontroller SUMMARY This chapter introduced integrated circuits and how they can be used with the BASIC Stamp A transistor was used as a current valve and a digital potentiometer was used to control the amount of current passing through the transistor Examining the digital potentiometer introduced the reference notch and pin map as important elements of electronic chips The function of each of the digital potentiometer pins was discussed as well as the device s internal structure The PBASIC command TOGGLE was introduced as a means to save program memory Questions 1 What are the names of the terminals on the transistor you used in this chapter 2 Which terminal controls the current passing through the transistor 3 What can you do to increase or decrease the current passing through the transistor Exercise 1 Write a program that adjusts the tap in the digital pot to position 0 regardless of its current setting Project 1 Add a photoresistor to your project and cause the brightness of the LED to adjust with the brightness seen by the photoresistor Solutions Q1 Emitte
158. arious web sites Using any search engine use the keywords RTTTL specification to review web pages that include the specification Here is an example of an RTTTL format ringtone TakeMeOut ToTheBallgame d 4 0 7 b 225 2c6 c a6 96 e6 2g9 6 2d6 p 2c6 c a6 96 e6 29 6 96 p p a6 g 6 a6 e6 f6 96 a6 p f6 2d6 p 2a6 a6 a6 b6 c d b6 a6 g6 The text before the first colon is what the cell phone displays as the name of the song In this case the ringtone is named TakeMeOut ToTheBallGame Between the first and second colon the default settings for the song are entered using d o and b Here is what they mean d duration o octave b beats per minute or tempo In the TakeMeOutToTheBallGame the default settings are d 4 0 7 b 225 The notes in the melody are entered after the second colon and they are separated by commas If just the note letter is used that note will be played for the default duration in the default octave For example the second note in TakeMeOutToTheBallGame is 1C Since it has no other information it will be played for the default quarter note duration d 4 in the seventh octave 0 7 A note could have up to five characters between the commas here is what each character specifies duration note sharp dot octave For example 29G 6 Page 328 What s a Microcontroller means play the half note G sharp for 1 the duration of a half note and play it in the sixth octave Here are a few
159. as some trouble shooting suggestions that you can repeat for this circuit Vdd is Vhs A ais ttipoo P15 Vdd Pid o oo0 a Figure 2 13 P11 Manual Test 470 Q P10 Circuit for i Second LED P14 P7 4709 T l 6 LED P3 LED P2 P1 iss Vss Vss X2 Disconnect power to your Board of Education or HomeWork Board Modify the second LED circuit you just tested by connecting the LED circuit s resistor lead input to P15 as shown in Figure 2 14 Page 58 What s a Microcontroller Vdd Vin bs Figure 2 14 x3 NEN Connecting pis LE Hoon the Second P14 mi gt imka LED to the iii H BASIC Pit Stamp eis P10 a Schematic P7 left and P6 iri pE wiring P4 diagram P3 P2 right P1 PO x2 Using a Program to Test the Second LED Circuit In Activity 2 you used an example program and the HIGH and Low commands to control the LED circuit connected to P14 These commands will have to be modified to control the LED circuit connected to P15 Instead of using HIGH 14 and Low 14 you will use HIGH 15 and Low 15 Example Program TestSecondLed bs2 Enter TestSecondLed bs2 into the BASIC Stamp Editor Connect power to your Board of Education or Home Work Board
160. at it reads PULSOUT 14 650 V Run the modified program and explain the differences in the positions the servo turns to and holds ACTIVITY 2 CONTROLLING POSITION WITH YOUR COMPUTER Factory automation often involves microcontrollers communicating with larger computers The microcontrollers read sensors and transmit that data to the main computer The main computer interprets and analyzes the sensor data then sends position information back to the microcontroller The microcontroller might then update a conveyer belt s speed or a sorter s position or some other mechanical motor controlled task You can use the Debug Terminal to send messages from your computer to the BASIC Stamp as shown in Figure 4 18 The BASIC Stamp has to be programmed to listen for the messages you send using the Debug Terminal and it also has to store the data you send in one or more variables ZIT ox Fj Z Baud Rate Figure 4 18 comi l asco ai A Sending Messages to Data Bits Flow Control wa n DIRT ATS e a o A o O Ta the BASIC Stamp Click the white field above the message display pane and type your message A copy of the message you entered appears in the lower windowpane This copy is called an echo In this activity you will program the BASIC Stamp to receive two values from the Debug Terminal 1 The number of pulses to send to the servo 2 The Duration value used by the PuLSouT command Page 120 What s a Microcontrolle
161. ate a one shot LED flasher When the program runs the LED flashes only once This is a way to look at the functionality of the Do LooPp You can temporarily remove the DO LOOP from the program by placing an apostrophe to the left of both the Do and Loop keywords as shown below DO HIGH 14 PAUSE 1000 LOW 14 PAUSE 2000 LOOP y Modify and re run the program using the code snippet above y Explain what happened why did the LED only flash once Commenting a line of code Placing an apostrophe to the left of a command changes it into a comment This is a useful tool because you don t actually have to delete the Wy command to see what happens if you remove it from the program It is much easier to add and remove an apostrophe than it is to delete and re type the commands ACTIVITY 3 COUNTING AND REPEATING In the previous activity the LED circuit either flashed on and off all the time or it flashed once and then stopped What if you only want the LED to flash on and off ten times Computers including the BASIC Stamp are great at keeping running totals of how many times something happens Computers can also be programmed to make Chapter 2 Lights On Lights Off Page 53 decisions based on a variety of conditions In this activity you will program the BASIC Stamp to stop flashing the LED on and off after ten repetitions Counting Parts and Test Circuit Use the example circuit shown in Figure 2 11 on page
162. ation It is up to you to remember to do this Always reconnect power to your Board of Education or BASIC Stamp HomeWork Board before downloading a program to the BASIC Stamp Build the circuit shown in Figure 3 3 Vdd 1 4 h 2 3 Figure 3 3 470 Q Pushbutton Test Circuit P5 X LED P3 P2 P1 PO Vss X2 Testing the Pushbutton When the pushbutton is not pressed the LED will be off If the wiring is correct when the pushbutton is pressed the LED should be on emitting light Warning signs If the Pwr LED on the Board of Education flickers goes dim or goes out completely when you plug the power supply back in it means you have a short circuit If gt this happens to you disconnect power immediately and find and correct the mistake in your e _ Circuit The Power LED on the HomeWork Board is different It glows only while a program is running If a program ends using the END command the Power LED will also turn off y Verify that the LED in your test circuit is off Page 74 What s a Microcontroller y Press and hold the pushbutton and verify that the LED emits light while you are holding the pushbutton down How the Pushbutton Circuit Works The left side of Figure 3 4 shows what happens when the
163. ax CD Welcome application shown in Figure 1 14 should run as soon as you load the CD into your computer s CD drive Chapter 1 Getting Started Page 9 If the Welcome application does not automatically run double click My Computer then double click your CD drive then double click Welcome Welcome to the Parallax Inc Product CD ROM Figure 1 14 The Parallax CD Browser Run or install Parallax product software Click the Software link shown in Figure 1 14 Click the next to the BASIC Stamps folder shown in Figure 1 15 Click the next to the Windows folder Click the floppy diskette icon labeled Stamp 2 2e 2sx 2p 2pe stampw exe Move on to Activity 2 Installing the Software ace ces Page 10 What s a Microcontroller Welcome to the Parallax Inc Product CD ROM Figure 1 15 The Parallax CD Description B BASIC Stamp 2 2e 2sx 2p software BASIC Stamps rowser for Windows95 98 NT 4 a bos np 2720 20 20 Stamow oxo Select the BASIC fed Stamp Plot Lite Stamp 2 2e 2sx 2p Stampw exe Stamp Editor installation H Javelin Stamps program from the H SXKey amp SX Blitz H Quadravox 306 Sound Module Software page m USB to Serial Adapter BAFO BF 810 Install Free downloads at the Parallax web site are included in the Parallax CD but only up to the date the CD was created The date on the front of the CD indicates when it was created If 1 the CD is just a f
164. bar Other lines are made by typing them in from the keyboard y Begin by clicking the BS2 icon the green diagonal chip on the toolbar shown highlighted in Figure 1 34 If you hold your cursor over this button its flyover help description Stamp Mode BS2 will appear y Next click on the gear icon labeled 2 5 shown highlighted in Figure 1 35 It s flyover help description is PBASIC Language 2 5 me Plt Oe 888 Bap edt _ __PBASIC Language 2 5 _ lt Stamp Mode B52 Figure 1 34 Figure 1 35 BS2 Icon PBASIC 2 5 Icon Clicking on this button will Clicking on this button will automatically automatically place STAMP BS2 place PBASIC 2 5 at the beginning at the beginning of your program of your program ALWAYS use these toolbar buttons to add these two lines as the beginning of every program Compiler directives use braces If you try to type in these parts of your ry J w program you may accidentally use parentheses or square brackets If you do this your program will not work y Type in the remaining 4 lines of the program exactly as shown in Figure 1 36 Page 22 What s a Microcontroller 7 BASIC Stamp C Program Files Parallax Inc Stamp Editor 2 0 Beta 1 B52 FirstProgram bs2 Ps oj xj Fi igure 1 36 File Edit Directive Run Help Deak a S nQ Qua Slag Areas aa mme Rl AARAA First Program Bu
165. bers this list is widely utilized by engineers hobbyists and students who share their BASIC Stamp projects and ask questions Stamps in Class Created for educators and students this list has about 650 subscribers who discuss the use of the Stamps in Class curriculum in their courses The list provides an opportunity for both students and educators to ask questions and get answers z Parallax Educators Exclusively for educators and those who contribute to the development of Stamps in Class Parallax created this group to obtain feedback on our curricula and to provide a forum for educators to develop and obtain Teacher s Guides g Parallax Translators Consisting of about 40 people the purpose of this list is to provide a conduit between Parallax and those who translate our documentation to languages other than English Parallax provides editable Word documents to our translating partners and attempts to time the translations to coordinate with our publications x Toddler Robot A customer created this discussion list to discuss applications and programming of the Parallax Toddler robot SX Tech Discussion of programming the SX microcontroller with Parallax assembly language tools and 3 party BASIC and C compilers Approximately 600 members z Javelin Stamp Discussion of application and design using the Javelin Stamp a Parallax module that is programmed using a subset of Sun Microsystems Java programming language Appr
166. blem modify DisplayDigitsWithLookup bs2 using the letter patterns worked out in Exercise 1 In the solution the letters have been set up as constants to make the program more intuitive Using the binary values is fine too but more prone to errors What s a Microcontroller Ch Prj01 FishAndChips bs2 Use a lookup table to store and display digits with a 7 segment display Spell out the message FISH CHIPS And dIP SSTAMP BS2 SPBASIC 2 5 Page 188 What s a Microcontroller Patterns of 7 Segment Display to create letters D JAE opra Eo eetis All LEDs must be outputs 19 chars in message 19 chars in message spacer Cy kl I BP Sy Sie n d space d I P space OUTH A CON 11110101 C CON 01100011 d CON 10010111 E CON 01110001 H CON 10110101 I CON 00100001 n CON 00010101 P CON 11110001 S CON 01110110 space CON 00000000 OUTH 00000000 DIRE S11 index VAR Byte DO DEBUG index OUTH Ws CES NRO E gt scarred face Ws Cee T ay CR FOR index 0 TO 18 LOOKUP index F I S H A DEBUG DP C2 man cesa aa PAUSE 400 NEXT LOOP Further Investigation As with all texts cited in this section this one is available for free download from www parallax com TSCM Olentisl CR 400 ms between letters StampWorks Workbook Version 1 2 Parallax Inc 2001 StampWorks is written by Nuts amp Volts author Jon Williams and features a wide This text is a collection of 3
167. ce all the note durations are fractions of a whole note you can use the duration of a whole note to set the tempo What does the Q in Notes DATA mean Q is for quit and a DO WHILE LOOP checks for Q each time through the loop How do I play a rest You can insert a rest between notes by inserting a P The Your 9 Tur section has the first few notes from Beethoven s 5 Symphony which has a rest in it How do play sharp flat notes NotesAndDurations bs2 has values in its lookup tables for sharp flat notes When you use the lower case version of the note it will play the flat note For example if you want to play B flat use b instead of B Remember that this is the same frequency as A sharp Example Program NotesAndDurations bs2 Enter and run NotesAndDurations bs2 V How does it sound What s a Microcontroller NotesAndDurations bs2 Chapter 8 Frequency and Sound Page 235 Play the first few notes from Frere Jacques SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running Notes DATA Cu p C C D E C B F G g F G Q Durations DATA 4 4 4 4 4 4 4 4 4 4 P e T 2 WholeNote CON 2000 index VAR Byte offset VAR Nib noteLetter VAR Byte noteFreq VAR Word noteDuration VAR Word DO UNTIL noteLetter Q READ Notes index noteLetter LOOKDOWN noteLetter As Toit Buy DOES Ua RAS EDRN HORG TEN ERR tept Gs Wiens Us Sa U
168. circuit shown in Figure 10 2 Figure 10 2 First Pushbutton Circuit X3 Vdd P3 220 Q 10 kQ Testing the First Pushbutton Circuit Writing a program to test this circuit should be very simple by now especially since you ve already done it before Example Program ReadPushbuttonState bs2 This is a repeat of the program for testing pushbuttons from Chapter 3 Enter and run the ReadPushbuttonState bs2 Verify that the BASIC Stamp is able to read the pushbutton y Correct any problems you catch before moving on to the next circuit Page 284 What s a Microcontroller What s a Microcontroller ReadPushbuttonState bs2 Check and send pushbutton state to Debug Terminal every 1 4 second SSTAMP BS2 SPBASIC 2 5 DO DEBUG IN3 PAUSE 250 LOOP Your Turn Building and Testing the Second Pushbutton Circuit Once the first pushbutton circuit has been built and tested the process can be repeated for the second pushbutton V Add the pushbutton circuit shown in Figure 10 3 Test the second pushbutton circuit by modifying ReadPushbuttonState bs2 so that it reads the circuit connected to P4 Run the program and verify that the second pushbutton works V Correct any problems you catch before moving on to the nex
169. citance If the capacitance is known and the resistance is variable then the discharge time gives an indication of the resistance As R gets larger the RC discharge time increases in direct proportion to the increase in R As R gets smaller the RC discharge time decreases in direct proportion to the decrease in R The con directive substitutes a name for a number new cap 10x old cap value 10x0 5uF uF Activity 4 with bi color LED added P13 Potentiometer schematic from Figure 5 11 1 p 150 servo from Figure 4 3 p 106 bi P A color LED from Figure 2 19 p 63 with s a P15 and P14 changed to P13 and P12 2 P12 4709 What s a Microcontroller Ch5Prj0l ControlServoWithPot bs2 Read potentiometer in RC time circuit using RCTIME command The time variable ranges from 126 to 713 and an offset of 330 is needed Bi color LED on P12 P13 tells direction of servo rotation green for CW red for CCW off when servo is holding position SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running time VAR Word time reading from potentiometer prevTime VAR Word previous reading DO P2 prevTime time HIGH 7 PAUSE 10 RCTIME 7 1 time time time 330 IF time gt prevTime 2 THEN HIGH 13 LOW 12 ELSEIF time lt prevTime 2 THEN LOW 13 HIGH 12 ELSE LOW 13 LOW 12 ENDIF PULSOUT 14 time LOOP Chapter 5 Measuring Rotation Page 163 Store previous time reading Read pot using RCT
170. click the Close button near the bottom of the window y In the Stamp Plot Lite window click Connect then click Plot Data Checkmarks should appear in each box after you click it Com Pott Stam Pose COM Port Settings com fcom1 L on Plot Data Debug Terminal left Data Bits Flow 4 F and Stamp Plot Lite a ug BE fiche y Press and release the Reset button on your Board of Education or HomeWork Board This starts the BASIC Stamp program over from the beginning which sends the DEBUG commands that configure Stamp Plot Lite y The data will start graphing as soon as you click Plot Data Hold you hand over the photoresistor at different distances to simulate different lighting conditions Remember the darker the shadow you cast the higher the value in the graph the brighter the light the smaller the value IMPORTANT Only one program can use a COM port at one time o __ Before attempting to run a different program using the BASIC Stamp Editor you must uncheck the Connect and Plot Data checkboxes in Stamp Plot Lite w Before reconnecting Stamp Plot Lite by clicking the Connect and Plot Data checkboxes you must close the Debug Terminal What s a Microcontroller PlotPhotoresistor bs2 Graph light levels using Stamp Plot Lite SSTAMP BS2 SPBASIC 2 5 time VAR Word DEBUG AMAX 1250 CR VIMEO 2QEM Ci MOEN OU Ci HONS Hibviaas NGG Ray ORS FG Chapter 7 Measu
171. coded in a constant named Dark to make the program easier to change What s a Microcontroller Ch07Prj01 PhotoresistorFlasher bs2 Make LED on P14 flash whenever a shadow is cast over the photoresistor Change Dark constant for your conditions SSTAMP BS2 PBASIC 2 5 Dark CON 215 time VAR Word DO HIGH 2 Read photoresistor with RCTIME PAUSE 100 RETLME N27 le Cime DEBUG HOME time DEC5 time Print value to Debug Terminal IF time gt Dark THEN Compare reading to known dark value HIGH 14 Blink LED on pin P14 PAUSE 100 LOW 14 PAUSE 100 ENDIF LOOP Further Investigation Applied Sensors Student Guide Version 2 0 Parallax Inc 2003 More in depth coverage of light measurement using a photodiode scientific units and math are featured in this text along with other sensor applications Industrial Control Student Guide Version 2 0 Parallax Inc 2002 Stamp Plot Lite was developed in conjunction with this text to demonstrate the fundamentals of techniques used in industrial process control Chapter 8 Frequency and Sound Page 219 Chapter 8 Frequency and Sound YOUR DAY AND ELECTRONIC BEEPS Here are a few examples of beeps you might hear during a normal day The microwave oven beeps when it s done cooking your food The cell phone plays different tones of beeps that resemble songs to get your attention when a call is coming in The ATM machine beeps to remind you not to for
172. command to see if your computer has this non standard serial port problem It is not likely but it would be important for you to know V Open LedOnOff bs2 Delete the entire DEBUG instruction V Run the modified program while you observe your LED If the LED blinks on and off continuously just as it did when you ran the original program with the DEBUG command your computer will not have this problem If the LED blinked on and off only once and then stopped you have a computer with a non standard serial port design If you disconnect the serial cable from your board and press the Reset button the BASIC Stamp will run the program properly without freezing In programs you write yourself you should add a single command DEBUG Program Running right after the compiler directives This will open the Debug Terminal and keep the COM port open This will prevent your programs from freezing after one pass through the Do Loop or any of the other looping commands you will be learning in later chapters You will see this command in some of the example programs that would not Chapter 2 Lights On Lights Off Page 51 otherwise need a DEBUG instruction So you should be able to run all of the remaining programs in this book even if your computer failed the diagnostic test Your Turn Timing and Repetitions By changing the PAUSE command s Duration argument you can change the amount of time the LED stays on and off For example b
173. complex mechanical problems Figure 1 4 shows two example robots On each of these robots students use the BASIC Stamp 2 to read sensors control motors and communicate with other computers The robot on Chapter 1 Getting Started Page 3 the left is Parallax Inc s Boe Bot The projects in the Robotics with the Boe Bot text can be tackled using the Boe Bot after you ve worked through the activities in this one The robot on the right was built by a group of students and entered into a First Robotics competition The goal of the contest is different each year In the example shown the goal was to see which group s robot could sort colored hoops the fastest Figure 1 4 Educational Robots Parallax Boe Bot left First Competition Robot right Other robots solve complex problems such as the autonomous remote flight robot shown at the left of Figure 1 5 This robot was built and tested by mechanical engineering students at the University of California Irvine They used a BASIC Stamp module to help it communicate with a satellite global positioning system GPS so that the robot could know its position and altitude The BASIC Stamp also read level sensors and controlled the motor settings to keep the robot flying properly The mechanical millipede robot on the right was developed by a professor at Nanyang Technical University Singapore It has more than 50 BASIC Stamp modules and they all communicate with each other in an el
174. controller DigitalPotUpDownWithToggle bs2 Sweep digital pot through values S STAMP BS2 PBASIC 2 5 DEBUG Program Running counter VAR Byte Chapter 9 Electronic Building Blocks Page 273 LOW 5 DO FOR counter 0 TO 127 PULSOUT 6 5 PAUSE 10 NEXT TOGGLE 5 LOOP Looking Inside the Digital Potentiometer Figure 9 8 shows a diagram of the potentiometer inside the AD5220 The AD5220 has 128 resistive elements each of which is 78 125 Q nominal value All 128 of these add up to 10 000 Q or 10 kQ A nominal value means a named value Parts like resistors and capacitors typically have a 1 nominal value and a tolerance Each of the AD5220 s resistive elements has a nominal v value of 78 125 Q with a tolerance of 30 23 438 Q above or below the nominal value Between each of these resistive elements is a switch called a tap Each switch is actually a group of transistors that are switched on or off to let current pass or not pass Only one of these switches can be closed at one time If one of the upper switches is closed like pos 125 126 or 127 it s like having the manual potentiometer knob turned most or all the way clockwise If pos 0 or 1 is closed it s like having a manual potentiometer turned most or all the way counterclockwise Ad5220 Figure 9 8 4092 pos 125 Inside the AD5220 Page 274 What s a Microcontroller Imagine that Pos 126 is closed If you want to
175. counter 1 TO pulses PULSOUT 14 duration PAUSE 20 NEXT DEBUG DONE PAUSE 1000 LOOP How ServoControlWithDebug bs2 Works Three Word variables are declared in this program counter Var WORD pulses Var WORD duration Var WORD Chapter 4 Controlling Motion Page 123 The counter variable is declared for use by a FoR NEXT loop See Chapter 2 Activity 3 for details The pulses and duration variables are used a couple of different ways They are both used to receive and store values sent from the Debug Terminal The pulses variable is also used to set the number of repetitions in the FOR NEXT loop that delivers pulses to the servo and the duration variable is used to set the duration for the PULSOUT command The rest of the program is nested inside a Do LooP without a WHILE or UNTIL argument so that the commands execute over and over again DO Rest of program not shown LOOP The DEBUG command is used to send you the user of the software a message to enter the number of pulses Then the DEBUGIN command waits for you to enter digits that make up the number and press the Enter key on your keyboard The digits that you enter are converted to a value that is stored in the pulses variable This process is repeated with a second DEBUG and DEBUGIN command that loads a value into the duration variable too DEBUG CLS Enter number of pulses CR DEBUGIN DEC pulses DEBUG Enter PULSOUT duration CR DEB
176. cts that value from 8 If noteOctave was 8 now it s 0 If noteOctave was 7 now it s 1 If noteOctave was 6 now it s 2 and if noteOctave was 5 now it s 3 noteOctave 8 noteOctave Now noteOctave is a value that can be used as an exponent of 2 but how do you raise 2 to a power in PBASIC One answer is to use the DCD operator DCD 0 is 1 DCD 1 is 2 DCD 2 is 4 and pcp 3 is 8 Dividing noteFreq by DCD noteOctave means you are dividing by 1 2 4 or 8 which divides noteFreq down by the correct value The end result is that noteFreq is set to the correct octave You will use the Debug Terminal in the Your Turn section to take a closer look at how this works noteFreq noteFreq DCD noteOctave How am I supposed to know to use the DCD operator Keep learning and practicing Every time you see a new command operator or any other keyword used in an example A look it up in the BASIC Stamp manual Read about it and try using it in a program of your own design Get in the habit of periodically reading the BASIC Stamp Manual and trying the w short example programs That s the best way to get familiar with the various commands and operators and how they work By doing these things you will develop a habit of always adding to the list of programming tools you can use to solve problems The first two lines of code for determining the note duration are about the same as the code from the previous example program Now
177. cuit connected to P3 is held down y Also check to make sure the LED in the circuit connected to P15 flashes while the pushbutton in the circuit connected to P4 is held down What s a Microcontroller PushbuttonControlOfTwoLeds bs2 Blink P14 LED if P3 pushbutton is pressed and blink P15 LED if P4 pushbutton is pressed SSTAMP BS2 0 PBASIC 2 5 DO Page 86 What s a Microcontroller DEBUG HOME DEBUG IN4 DEBUG IN3 IF IN3 1 THEN HIGH 14 PAUSE 50 ELSEIF IN4 1 THEN HIGH 15 PAUSE 50 ELSE PAUSE 50 ENDIF LOW 14 LOW 15 PAUSE 50 LOOP How PushbuttonControlOfTwoLeds bs2 Works If the display of IN3 and IN4 scrolled down the Debug Terminal as they did in the previous example it would be difficult to read One way to fix this is to always send the cursor to the top left position in the Debug Terminal using the Home formatter DEBUG HOME By sending the cursor to the home position each time through the Do Loop the commands DEBUG IN4 DEBUG IN3 display the values of In4 and INn3 in the same part of the Debug Terminal each time The Do keyword begins the loop in this program DO These commands in the IF statement are the same as the ones in the example program from the previous activity IF IN3 1 THEN HIGH 14 Chapter 3 Digital Input Pushbuttons Page 87 PAUSE 50 This is where the ELSEIF keyword helps If IN3 is not 1 but IN4 is 1 we want to turn the LED connect
178. d the program should function normally If power is disconnected and reconnected the program should behave as though the kill switch has been pressed Solutions Q1 1 Plug Connects servo to power and signal sources 2 Cable Conducts power and signals from plug into the servo 3 Horn The moving part of the servo 4 Case Contains DC motor gears and control circuits Q2 No the LED just helps us see what s going on with the control signals Q3 The low time is controlled with the PAUSE command The high time is controlled with the puLSouT command Q4 A For NEXT loop Q5 Click the white field above the message display pane in the Debug Terminal and type the message you d like to send Use the DEBUGIN command to receive the typed characters in the BASIC Stamp Q6 A nested IF THEN statement El a b Add STEP 4 to both FOR loops FOR counter 700 TO 800 FOR counter 700 TO 800 STEP 4 PULSOUT 14 counter PULSOUT 14 counter PAUSE 20 Peo 20 NEXT NEXT On BAUS BOs OTE FOR counter 800 TO 700 STEP 4 PULSOUT 14 counter PULSOUT 14 counter PAUSE 20 PAUSE 20 NEXT NEXT Page 136 What s a Microcontroller E2 FOR counter 700 TO 800 STEP 4 FOR pulses 1 TO 10 PULSOUT 14 counter PAUSE 20 NEXT NEXT FOR counter 800 TO 700 STEP 4 FOR pulses 1 TO 10 PULSOUT 14 counter PAUSE 20 NEXT NEXT P1 There are many possible solutions one is given below What s a Microcontroller Ch04
179. d high tech gizmos You will also write computer programs that the BASIC Stamp module will run These programs will make the BASIC Stamp module monitor and control these circuits so that they perform useful functions Page 2 What s a Microcontroller Figure 1 2 The BASIC Stamp 2 Microcontroller Module BASIC Stamp 2 modules are the most popular microcontrollers made by Parallax Inc In this text BASIC Stamp refers to Parallax Inc s BASIC Stamp 2 microcontroller module There are other BASIC Stamp modules some of which are shown in Figure 1 3 Each BASIC Stamp module is color coded The BASIC Stamp 2 is green The BASIC Stamp 2e is red The BASIC Stamp 2SX is blue and the BASIC Stamp 2p is gold Each variation on the BASIC Stamp 2 is slightly different featuring higher speed more memory additional functionality or some combination of these extra features Se Figure 1 3 Eits BASIC Stamp rary Modules From Left to Right BASIC Stamp 2 2e 2SX and 2p AMAZING INVENTIONS WITH BASIC STAMP MICROCONTROLLERS Consumer appliances aren t the only things that contain microcontrollers Robots machinery aerospace designs and other high tech devices are also built with microcontrollers Let s take a look at some examples that were created with BASIC Stamp modules Robots have been designed to do everything from helping students learn more about microcontrollers to mowing the lawn to solving
180. e Setup Stamp Editor v2 0 Beta 1 6MB exa My Network P Save as type Application X Cancel V Wait while the BASIC Stamp Editor installation program downloads shown in Figure 1 12 This may take a while if you are using a modem connection When the download is complete leave the window shown in Figure 1 13 open while you skip to the next section Activity 2 Installing the Software Download complete 15 x yb Download Complete Saved Editor_v2 0_Beta_1_6MB exe from www parallax com PTET TT Downloaded 6 01 Download to SSetup_Stamp_Editor_v2 0_Beta_1_6MB exe Transfer rate 1 20 MB Sec 53 of Setup_Stamp_Editor_ 2 0_Beta_1_6MB_exe lai Ea oe Saving Editor_v2 0_Beta_1_6MB exe from www parallax com a Estimated time left 1 min 59 sec 79 4 KB of 6 01 MB copied Download to Setup_Stamp_E ditor_v2 0_Beta_1_6MB exe Transfer rate 51 3KB Sec Open Open Folder Cose Open Open Felder Figure 1 12 Download Progress Window Figure 1 13 Download Complete Finding the Software on the Parallax CD You can also install the BASIC Stamp Editor from the Parallax CD but it has to be May 2003 or newer so that you can get the version of the BASIC Stamp Editor that is compatible with the examples in this text You can find the Parallax CD s Year and Month by examining the labeling on the front of the CD y Place the Parallax CD into your computer s CD drive The Parall
181. e Set values of I O pins connected to CLK and U D Counter for FOR NEXT Previous tap setting New tap setting Initialize new and old tap settings to zero Page 276 What s a Microcontroller LOW UdPin Set U D pin for Down FOR counter 0 TO 127 Set tap to lowest position PULSOUT 6 5 PAUSE 1 NEXT DO GOSUB Get_New Tap Setting User display and get input GOSUB Set_Ud_ Pin Set U D pin for up down GOSUB Pulse Clk pin Deliver pulses LOOP U Sitlereiuiestines o sass aoa se see Sees SSS SS SSS SS SS SSS SS SSS SSS SS SSS SESS Get New Tap Setting Display instructions and get user input for new DEBUG CLS Tap setting is tap setting value DEC newTapSetting CR CR DEBUG Enter new tap CR setting 0 TO 127 DEBUGIN DEC newTapSetting RETURN Set_Ud_Pin Examine new and old tap values to decide value of U D pin IF newTapSetting gt oldTapSetting THEN Notify user if values are HIGH UdPin equal oldTapSetting oldTapSetting 1 Increment for Pulse Clk pin ELSEIF newTapSetting lt oldTapSetting THEN LOW UdPin oldTapSetting oldTapSetting 1 Decrement for Pulse Clk pin ELSE DEBUG CR New and old settings CR Ware the sane bry CR vagad Tera GR PAUSE DelayReader Give reader time to view ENDIF Message RETURN Pulse Clk pin Deliver pulses from old to new values Keep in mind that Set_Ud_ Pin adjusted the value of oldTapSetting tow
182. e AN below fF P12 P11 220 Q P10 10 kQ P9 P8 Vss Binary and Circuits The base 2 number system uses only the digits 1 and 0 to make numbers and these binary values can be transmitted from one device to another The BASIC Stamp interprets Vdd 5 V as binary 1 and Vss 0 V as binary 0 Likewise when l the BASIC Stamp sets an I O pin to Vdd using HIGH it sends a binary 1 When it sets an I O pin to Vss using LOW it sends a binary 0 This is a very common way of communicating binary numbers used by many computer chips and other devices Programming the BASIC Stamp to Monitor the Pushbutton The BASIC Stamp stores the one or zero it senses at I O pin P3 in a memory location called 1n3 Here is an example program that shows how this works Example Program ReadPushbuttonState bs2 This program makes the BASIC Stamp check the pushbutton every 4 second and send the value of IN3 to the Debug Terminal Figure 3 8 shows the Debug Terminal while the program is running When the pushbutton is pressed the Debug Terminal displays Page 78 What s a Microcontroller the number 1 and when the pushbutton is not pressed the Debug Terminal displays the number 0 47 Debug Terminal 1 lo x Com Port Baud Rate Parity comi s0 E None E Figure 3 8 Data Bits Flow Control 1x I DIR I RTS z i oa SO Debug Terminal Displaying Pushbutton States The Debug Terminal displays 1 when the pushbutton is pressed and 0
183. e 323 Vdd Vss 5 V The voltage electrical pressure from Vdd to Vss is 5 V This is called regulated voltage and it works about the same as a battery that is exactly 5 V Vin Vss 9 V If you are using 9 V battery the voltage from Vin to Vss is 9 V Be careful If you are using a voltage regulator that plugs into the wall even if it says 9 V it could go as high as 18 V Ground and or reference refer to the negative terminal of a circuit When it comes to the BASIC Stamp and Board of Education Vss is considered the ground reference It is zero volts and if you are using a 9 V battery it is that battery s negative terminal The battery s positive terminal is 9 V Vdd is 5 V above the Vss reference of 0 V and it is a special voltage made by a voltage regulator chip to supply the BASIC Stamp with power _ J Ohm s Law V I R The voltage measured across a resistor s terminals V equals the v current passing through the resistor I times the resistor s resistance R Diode Forward Voltage When an LED is emitting light the voltage measured from anode to cathode will be around 1 6 V Regardless of whether the current passing through it is a large or a small value the voltage will continue to be approximately 1 6 V Kirchoff s Voltage Law Simplified voltage used equals voltage supplied If you supply a circuit with 5 V the number of volts all the parts use had better add up to 5 V Kirchoff s Current Law Si
184. e between the potentiometer s A and W terminals Parts for Reading RC Time with the BASIC Stamp 1 Potentiometer 10 kQ 1 Resistor 220 Q red red brown 2 Jumper wires 1 Capacitor 0 1 uF shown in Figure 5 10 1 Capacitor 0 01 uF also shown in Figure 5 10 2 Jumper wires e These capacitors do not have and terminals You can safely connect these 1 wy capacitors to a circuit without worrying about positive and negative terminals Page 150 What s a Microcontroller Figure 5 10 0 1 pF Ceramic Capacitors ale The 0 1 uF capacitor above and the 0 01 uF capacitor below are both non polar 0 01 uF You will not have to worry ae about positive and negative leads with these two parts Building an RC Time Circuit for the BASIC Stam Figure 5 11 shows a schematic for the fast RC time circuit and Figure 5 12 shows the wiring diagram This is the circuit that you will use to monitor the position of the potentiometer s input shaft with the help of the BASIC Stamp and a PBASIC program y Build the circuit shown in Figure 5 11 P7 220 Q Pot 10 kQ 0 1 uF Figure 5 11 BASIC Stamp RCTIME Circuit with Potentiometer Chapter 5 Measuring Rotation Page 151 Vdd Vin Vss X3 P
185. e resistance between the A and W terminals changes This in turn changes the current flow through the LED circuit ACTIVITY 2 MEASURING RESISTANCE BY MEASURING TIME This activity introduces a new part called a capacitor A capacitor behaves like a rechargeable battery that only holds its charge for short durations of time This activity also introduces RC time which is an abbreviation for resistor capacitor time RC time is a measurement of how long it takes for a capacitor to lose a certain amount of its stored charge as it supplies current to a resistor By measuring the time it takes for the capacitor to discharge with different size resistors and capacitors you will become more familiar with RC time In this activity you will program the BASIC Stamp to charge a capacitor and then measure the time it takes the capacitor to discharge through a resistor Introducing the Capacitor Figure 5 7 shows the schematic symbol and part drawing for the type of capacitor used in this activity Capacitance value is measured in microfarads uF and the measurement is typically printed on the capacitors The cylindrical case of the capacitor is called a canister This capacitor has a positive and a negative terminal The negative terminal is the lead that comes out of the metal canister closest to the stripe with a negative sign Always make sure to connect these terminals as shown in the circuit diagrams Connecting w one of the
186. e uy 4 offset LOOKUP offset lL AGO wes Ae BOs Bway 2349 2489 2637 2794 2960 3136 3322 0 0 noteFreq READ Durations index noteDuration noteDuration WholeNote noteDuration FREQOUT 9 noteDuration noteFreqg index index 1 LOOP END Page 236 What s a Microcontroller How NotesAndDurations bs2 Works The Notes and Durations DATA directives were discussed before the program These directives combined with the WholeNote constant are used to store all the musical data used by the program The declarations for the five variables used in the program are shown below Even though a FOR NExT loop is no longer used to access the data there still has to be a variable index that keeps track of which Data entry is being read in Notes and Durations The offset variable is used in the LOOKDOWN and LOOKUP commands to select a particular value The noteLetter variable stores a character accessed by the READ command LOOKUP and LOOKDOWN commands are used to convert this character into a frequency value This value is stored in the noteFreq variable and used as the FREQOUT command s Freq1 argument The noteDuration variable is used in a READ command to receive a value from the Durations DATA It is also used to calculate the Duration used in the FREQOUT command index VAR Byte offset VAR Nib noteLetter VAR Byte noteFreq VAR Word noteDuration VAR Word The main loop keeps executing until the letter Q is read
187. eWithCharacters bs2 Program that can identify some characters case digit punctuation SSTAMP BS2 SPBASIC 2 5 character VAR Byte DEBUG Enter a character CR DO DEBUGIN character SELECT character CASE A TO Vi DEBUG CR Upper case CR CAS Hct TO on DEBUG CR Lower case CR CASE 0 TO 9 DEBUG CR Digit CR CASE UR KDI VORU VN DEBUG CR Punctuation CR CASE ELSE DEBUG CR Character not known CR Try a different one ENDSELECT DEBUG CR Enter another character CR LOOP Page 250 What s a Microcontroller How SelectCaseWithCharacters bs2 Works When compared to SelectCaseWithValues bs2 this example program has a few differences First the name of the value variable was changed to character and its size was changed from word to byte This is because all characters in PBASIC are byte size The SELECT statement chooses the character variable for case by case evaluation SELECT character The quotation marks are used to tell the BASIC Stamp Editor that you are referring to characters SELECT character CASE A to Z DEBUG CR Upper case CR CASE a to Ng DEBUG CR Lower case CR CASE 0 to 9 DEBUG CR Digit CR CASE 1 pm om lm onion DEBUG CR Punctuation CR There is also one different CASE statement that was not used in the previous example CASE ELSE DEBUG CR Character not known CR Try a different one This CA
188. eaker into the program The key to solving this problem is to use the STR formatter with DEBUG The text introduced the STR formatter with DEBUGIN so it makes sense to guess that the STR formatter will also work with DEBUG This can be done by adding this line of code below the DEBUGIN statement DEBUG CR CR You entered STR userEntry CR Project 1 uses the same schematic as Figure 10 1 p 282 with the addition of a piezo speaker connected to P11 What s a Microcontroller P11 D z TestPiezoWithFreqout bs2 ad Send a tone to the piezo speaker using the FREQOUT command SSTAMP BS2 SPBASIC 2 5 DEBUG Tone sending CR FREQOUT 11 1500 2000 DEBUG Tone done Project 2 uses the same schematic as Project 1 What s a Microcontroller Ch10Prj02 AddSpeakerToSensorArray bs2 Use Debug Terminal to choose to read one of five sensors Project 2 Add a 5th menu item that makes a piezo speaker beep one IL xeyelialels GNe Zl iereSleybisiaveyyy Sie Aisles SSTAMP BS2 SPBASIC 2 5 Pb1iPin CON Pb2Pin CON PotPin CON PhotoPin CON SpkrPin CON J soees Constants DelayRc CON DelayReader CON o Variables request VAR time VAR DO GOSUB Display Menu GOSUB Get_Request rPwoN FW Chapter 10 Running the Whole Show Page 299 ON request GOSUB Read_Pushbutton_1 Read_Pushbutton_2 LOOP eens Subroutines Display Menu DEBUG CLS MENU RETURN Get_Request Ui Gist tele
189. eatsPerMin first you can do this wholeNote 60000 beatsPerMin 4 This is all the same as the previous program DO UNTIL noteLetter Q READ Notes index noteLetter LOOKDOWN noteLetter ben uge Dp Majty TEN p igh ng a A b B ph on i j offset Now that octaves are in the mix the part of the code that figures out the note frequency has changed The Looxup command s table of values contains note frequencies from the 8 octave These values can be divided by 1 if you want to play notes in the 8 octave by 2 if you want to play notes in the 7 octave by 4 if you want to play notes in the 6 octave and by 8 if you want to play notes in the 5 octave The division happens next All this Looxup command does is place a note from the 8 octave into the noteFreq variable LOOKUP offset 4186 4435 4699 4978 5274 5588 5920 6272 6645 7040 7459 7902 0 0 noteFreq Here is how the noteFreq variable is adjusted for the correct octave First the READ command grabs the octave value stored in the Octaves DATA This could be a value between 5 and 8 READ Octaves index noteOctave Chapter 8 Frequency and Sound Page 243 Depending on the octave we want to divide noteFreq by either 1 2 4 or 8 That means that the goal is really to divide by 2 1 2 2 27 4 or 2 8 The statement below takes the value of noteOctave which could be a value between 5 and 8 and subtra
190. eceive Capture Macros Pause Clear Close I Echo Off Chapter 8 Frequency and Sound Page 247 Example Program SelectCaseWithValues bs2 V Enter and run SelectCaseWithValues bs2 y Click the Debug Terminal s Transmit Windowpane V Enter a value between 0 and 65535 and press the Enter key _ What happens if you enter a number larger than 65535 If you enter the number 65536 9 the BASIC Stamp will store the number 0 If you enter the number 65537 the BASIC Stamp amp will store the number 1 and so on When a number is too large for the variable it fits into it is called overflow y Use Table 2 2 to verify that the example program makes the right decisions about the size of the numbers you enter into the Debug Terminal Table 2 2 Variable Types and Values They Can Store Variable type Range of Values Bit 0 to 1 Nib 0 to 15 Byte 0 to 255 Word 0 to 65535 What s a Microcontroller SelectCaseWithValues bs2 Enter a value and see the minimum variable size required to hold it SSTAMP BS2 PBASIC 2 5 value VAR Word DEBUG Enter a value from toT OAIE DO DEBUGIN DEC value SELECT value CASE 0 1 DEBUG Bit CR PAUSE 100 CASE 2 TO 15 DEBUG Nib Nibble CERF CR Page 248 What s a Microcontroller PAUSE 200 CASE 16 TO 255 DEBUG Byte CR PAUSE 300 CASE 256 TO 65535 DEBUG Word CR PAUSE 400 ENDSELECT DEBUG
191. ed to P15 on instead of the one connected to P14 ELSEIF IN4 1 THEN HIGH 15 PAUSE 50 If neither statement is true we still want to pause for 50 ms without changing the state of any LED circuits ELSE PAUSE 50 When you re finished with all the decisions don t forget the ENDIF ENDIF It s time to turn the LEDs off and pause again You could try to decide which LED you turned on and turn it back off PBASIC commands execute pretty quickly so why not just turn them both off and forget about more decision making LOW 14 LOW 15 PAUSE 50 The Loop statement sends the program back up to the Do statement and the process of checking the pushbuttons and changing the states of the LEDs starts all over again LOOP Your Turn What about Pressing Both Pushbuttons The example program has a flaw Try pressing both pushbuttons at once and you ll see the flaw You would expect both LEDs to flash on and off but they don t because only one code block in an IF ELSEIF ELSE statement gets executed before it skips to the ENDIF Here is how you can fix this problem V Save PushbuttonControlOffwoLeds bs2 under a new name y Replace this 1F statement and code block IF IN3 1 THEN Page 88 What s a Microcontroller HIGH 14 PAUSE 50 with this IF ELSEIF statement IF IN3 1 AND IN4 1 THEN HIGH 14 HIGH 15 PAUSE 50 ELSEIF IN3 1 THEN HIGH 14 PAUSE 50 or A code block is a group of comm
192. ee p CR FOR eepromAddress 0 TO 58 STEP 2 READ eepromAddress Word time DEBUG DEC2 eepromAddress D ipate isine Cr NEXT END How ReadLightMeasurementsFromEeprom bs2 Works As with the WRITE command the READ command uses byte size addresses Since words are being read from the EEPROM the eepromAddress variable has to have 2 added to it each time through the For NEXT loop FOR eepromAddress 0 to 58 STEP 2 The READ command gets the word size value at eepromAddress This value is loaded into the time variable READ eepromAddress Word time The value of the time and eepromAddress variables are displayed as columns in a table in the Debug Terminal DEBUG DEC2 eepromAddress DEC time CR NEXT Your Turn Plotting the Stored Data y Modify ReadLightMeasurementsFromEeprom bs2 so that it displays the data to Stamp Plot Lite Remember the DEBUG statement must only display the value and a carriage return ACTIVITY 4 SIMPLE LIGHT METER Light sensor information can be communicated in a variety of ways The light meter you will work with in this chapter changes the rate that the display flickers depending on the light intensity it detects Page 204 What s a Microcontroller Light Meter Parts 1 Photoresistor 1 Resistor 220 Q red red brown 1 Capacitor 0 01 uF 1 Capacitor 0 1 UF 1 7 segment LED display 8 Resistors 1 kQ brown black red 6 Jumper wires Building the Light
193. eeeeceeeeeeeeeeeeeaeeeeeeceeeteseeeeees 193 Activity 3 Tracking Light Events ccccccceceeeceeeeeeeeeeeeeeeeeeeeeeeeeeneeeeeeeseeesesneeees 197 Activity 4 Simple Light Meter ccccccccceeeeeeeeeeeeceeeeeeeeeeeeeeeeeeeesaeeeeseceeetesneeees 203 SUMMA iieii desc ies even a e deevhe vedere e TE ET Ee 215 Chapter 8 Frequency and Sound sssssssunessnneenneennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn ennnen nnn 219 Your Day and Electronic Beeps cccccccceeeeeeeeneeeeeeeeeeeeenaeeeeeeeeeeeeeaaeeeeeeeeeeeeeaaeeees 219 Microcontrollers Speakers Beeps and On Off Signals cceceeeeeeeeeteeeeetees 219 Activity 1 Building and Testing the Speaker ccccccccceeeeeeeeeeeeeeeeeeeeeeeeeseeeees 220 Activity 2 Action SOUNAS 2 02 ec2h 02 ee eet toe Seed hte Selenite oe oe od 222 Activity 3 Musical Notes and Simple Song 2 ccceeceeeeeeeeeeeeeeeeeeeeeeeeeeeneeeees 227 Activity 4 Microcontroller MUSIC ccceeeeceeeeeeeeeeeeeeeeeeeeeeeeeeecaeeeeesseeeetesnaeeess 233 Activity 5 Cell Phone RingTones ccceceeeceeeeeeceeeeeeeeeeeeeeeeeeeseaeeeeesceeeeeeneees 245 Table of Contents Page iii SDUIITUIMIANY a ete Se ese ae ee aca Ge ec ee ee a Yd cel 258 Chapter 9 Electronic Building BIOCKS csscccesecsseeeeseeeenseeeeeeesesseeeeneeeeneas 263 Those Little Black Chips 2240 2 a se eee eel ee li eels 263 Expand Your Projects with P
194. en green then off in a loop SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running DO HIGH 15 Y Red LOW 14 PAUSE 500 LOW 15 r Green HIGH 14 PAUSE 500 LOW 15 DOLE LOW 14 PAUSE 500 LOOP Your Turn Lights Display In Activity 3 a variable named counter was used to control how many times the LED blinked What happens if you use the value counter to control the PAUSE command s Duration argument Rename and save TestBiColorLed bs2 as TestBiColorLedYourTurn bs2 Adda counter variable declaration before the Do statement Page 66 What s a Microcontroller counter VAR BYTE Nest the FoR NEXT loop below within the Do LOoP FOR counter 1 to 50 HIGH 15 LOW 14 PAUSE counter LOW 15 HIGH 14 PAUSE counter NEXT When you are done your code should look like this counter VAR BYTE DO FOR counter 1 to 50 HIGH 15 LOW 14 PAUSE counter LOW 15 HIGH 14 PAUSE counter NEXT LOOP At the beginning of each pass through the FOR NEXT loop the PAUSE value Duration argument is only one millisecond Each time through the For NExT loop the pause gets longer by one millisecond at a time until it gets to 50 milliseconds The DO LOOP causes the ForR NEXT loop to execute over and over again V Run the modified program and observe the effect Chapter 2 Lights On Lights Off Page 67 SUMMARY The BASIC Stamp can be programmed to switch a circuit with a light emitting d
195. enter When the Debug Terminal prompts you to Enter PULSOUT duration type the number 850 then press enter The PULSOUT Duration should be a number between 500 and 1000 If you enter numbers outside that range the servo may try to rotate to a position beyond its own mechanical limits Although it will not break the servo it could shorten the device s lifespan The BASIC Stamp will display the message Servo is running while it is sending pulses to the servo When it is done sending pulses to the servo it will display the message Done for one second Then it will prompt you to enter the number of pulses again Have fun with it but make sure to follow the directive in the caution box about staying between 500 and 1000 for your puLsouT value Page 122 What s a Microcontroller y Experiment with entering other values between 500 and 1000 for the PULSOUT Duration and values between 1 and 65534 for the number of pulses A i it takes between 40 and 45 pulses to make the servo hold a position for 1 second v What s a Microcontroller ServoControlWithDebug bs2 Send messages to the BASIC Stamp to control a servo using the Debug Terminal SSTAMP BS2 PBASIC 2 5 counter Var Word pulses Var Word duration Var Word DO DEBUG CLS Enter number of pulses CR DEBUGIN DEC pulses DEBUG Enter PULSOUT duration CR DEBUGIN DEC duration DEBUG Servo is running CR FOR
196. er called C sharp C or D flat D Whether a key is called sharp or flat depends on the particular piece being played and the rules for that are better left to the music classes Figure 8 3 Rightmost Piano Keys and Their Frequencies N WO O N N O O o ty OY o wv O q N Q O A Q O Ww o O 0 oO qA AN AN O N O Q0 A To r AN N oQ Chapter 8 Frequency and Sound Page 229 Tuning Method The keyboard in Figure 8 3 uses a method of tuning called equal temperament The frequencies are determined using a reference note then multiplying it by 202 for values of n 1 2 3 etc For example you can take the frequency for A6 and multiply by 2 to get the frequency for A6 Multiply it by 2 to get the frequency for B6 and so on Here is an example of calculating the frequency for B6 using A6 as a reference frequency The frequency of A6 is 1760 22 4 1224 1760 X 1 224 1975 5 1975 5 is the frequency of B6 Programming Musical Notes The FREQOUT command is also useful for musical notes Programming the BASIC Stamp to play music using a piezospeaker involves following a variety of rules used in playing music using any other musical instrument These rules apply to the same elements that were used to make sound effects frequency duration and pause This next example program plays some of the musical note frequencies on the piezospeaker each with a duration of half a second Example P
197. erence Notch Figure 9 5 AD5220 Pin Map Use the reference notch to make sure you have the AD5220 right side up when building it into your circuit on the breadboard AD5220 Here is a summary of each of the AD5220 s pins and functions 1 CLK The pin that receives clock pulses low high low signals to move the wiper terminal 2 U D The pin that receives a high signal to make the wiper W1 terminal move towards A1 and a low signal to make it move towards B1 This pin just sets the direction the wiper terminal doesn t actually move until a pulse a low high low signal is sent to the CLK pin Al The potentiometer s A terminal 4 GND The ground connection The ground on the Board of Education and BASIC Stamp HomeWork Board is the Vss terminal 5 W1 The potentiometer s wiper W terminal U Chapter 9 Electronic Building Blocks Page 269 6 B1 The potentiometer s B terminal 7 CS The chip select pin Apply a high signal to this pin and the chip ignores all control signals sent to CLK and U D Apply a low signal to this pin and it acts on any control signals it receives 8 Vdd Connect to 5 V which is Vdd on the Board of Education and BASIC Stamp Home Work Board The AD5220 Part Datasheet To see the part datasheet for the AD5220 Go to e www analog com Enter AD5220 into the Search field on Analog Devices home page and l1 click the Search button Click the Dat
198. eripheral Integrated Circuits ccceeeeeeeeeeees 264 Activity 1 Control Current Flow with a Transistor cccccccceeeeeeeeeeeeeeeeeeeeeeeeeees 265 Activity 2 Introducing the Digital Potentiometer ccccccceeeeeeeeeeeeeeeeeeeeeeeetees 267 SUMMARY a ects teva eet ee ett eat ad wate seater te et tee et een eee et ets a 278 Chapter 10 Running the Whole Show cssecccesecesseeeeseeeeneeeeseeeeeseeeeeeeeeneae 281 subsystem Integral OT cee ade teeta ee ede eet ee ecicct eet eee ee es 281 Activity 1 Building and Testing Each Pushbutton Circuit cceceeeeeeereeeeees 282 Activity 2 Building and Testing Each RC Time Circuit cecceeeeeeeeeeeeeeeeeeeee 285 Activity 3 Subsystem Integration Example ccccccceeeeeeeeeeeeeeeeeeseeeeeeseeeetees 287 Activity 4 Developing and Adding a Software Subsystem c esceeeeeeeeeeeeees 291 10a nla ANY ese Be EE ae eh Oe a ag ls Ge Le Ea oe Leech Be 297 Appendix A USB to Serial Adapter cccsccssseeeeseeeseteeeseeeeseeeeeeeeesseeeneeeeeeseeess 301 Appendix B Equipment and Parts Lists cccccseccceeeeeeseeeeeeeseeeeneeseeeesnenseeeenes 303 Appendix C BASIC Stamp and Carrier Board Components and Functions 307 Appendix D Batteries and Power Supplies cs ccesccsseeeseeeesseeeeseeeenseeeeeseeees 311 Appendix E Trouble Shooting s ecccsecceseeeeseeeeeeeeeeeeeseseaee
199. ertain duration of time in milliseconds A f What s a Millisecond A millisecond is 1 1000 of a second It is abbreviated as ms It ow takes 1000 ms to equal one second The command Low 14 causes the BASIC Stamp to internally connect I O pin P14 to Vss This turns the LED off Since Low 14 is followed by another Pause 500 the LED stays off for half a second The reason the code repeats itself over and over again is because it is nested between the PBASIC keywords Do and Loop Figure 2 12 shows how a Do LooP works By placing the code segment that turns the LED on and off with pauses between Do and Loop it tells the BASIC Stamp to execute those four commands over and over again The result is that the LED flashes on and off over and over again It will keep flashing until you disconnect power press and hold the Reset button or until the battery runs out Page 50 What s a Microcontroller DO HIGH 14 Figure 2 12 DO LOOP PAUSE 250 LOW 14 The code between the keywords DO and PAUSE 250 LOOP get executed LOOP over and over again A Diagnostic Test for your Computer A very few computers such as some laptops will halt the PBASIC program after the first time through a Do LOOP loop These computers have a non standard serial port design By placing a DEBUG command the program LedOnOff bs2 the open Debug Terminal prevents this from possibly happening You will next re run this program without the DEBUG
200. es their former values Chapter 7 Measuring Light Page 193 V Before you move on to the next activity return the circuit to the original one shown in Figure 7 2 by removing the 0 1 uF capacitor and replacing it with the 0 01 uF capacitor ACTIVITY 2 GRAPHING LIGHT MEASUREMENTS Factories often have to monitor many sensor inputs to make sure the products they make turn out right From light levels in a greenhouse to fluid levels in an oil refinery to temperature levels in a nuclear reactor the people responsible for controlling these levels often rely on graphs of the sensor measurements to get the information they need Introducing Stamp Plot Lite Figure 7 4 shows Stamp Plot Lite software graphing RC time measurements sent by the BASIC Stamp The line shown in Figure 7 4 is much easier to understand than the 250 RC time measurements that were used to plot that line Viewing the graph from left to right the RC time measurements gradually get larger and then suddenly drop off Since RC time measurements get larger when the light levels decrease and smaller when they increase the graph tells a story It looks like the light level being measured declined gradually and then it suddenly increased again he _ reales Range 22000 ci E Span 20008 Le Amio bee ici fol EUN Coe i ne E aA Pi Figure 7 4 sd po Time V aa on i ew Stamp Plot Lite Fae wim Graphing r Save data 7300 f2n aze toe ms Measured Light sooo
201. essing and displaying values from the three pata directives Ll 2 What s a Microcontroller TwinkleTwinkle bs2 Play the first seven notes from Twinkle Twinkle Little Star SSTAMP BS2 PBASIC 2 5 Notes DATA vom nen G G man man G Frequencies DATA Word 2093 Word 2093 Word 3136 Word 3136 Word 3520 Word 3520 Word 3136 Durations DATA Word 500 Word 500 Word 500 Word 500 Word 500 Word 500 Word 1000 index VAR Nib noteLetter VAR Byte noteFreq VAR Word noteDuration VAR Word DEBUG Note Duration Frequency CR Woese ee ee ee eee ee ee p CR FOR index 0 TO 6 READ Notes index noteLetter DEBUG noteLetter READ Durations index 2 Word noteDuration DEBUG DEC4 noteDuration READ Frequencies index 2 Word noteFreg DEBUG DEC4 noteFreq CR FREQOUT 9 noteDuration noteFreq NEXT END Your Turn Adding and Playing More Notes This program played the first seven notes from Twinkle Twinkle Little Star The words go Twin kle twin kle lit tle star The next phrase from the song goes How I won der Chapter 8 Frequency and Sound Page 233 what you are and its notes are F F E E D D C As with the first phrase the last note is held twice as long as the other notes To add this phrase to the song from TwinkleTwinkle bs2 you will need to expand each pata directive appropriately Don t forget to change the FoR NEXT loop so that it goes from 0 to 13
202. estions exercises and projects with solutions in each chapter summary The independent learner can work at his or her own pace and obtain assistance through the Stamps in Class Yahoo Group forum cited below SUPPORT AND DISCUSSION GROUPS The following two Yahoo Discussion Groups are available for those who would like support in using this text These groups are accessible from www parallax com under Discussion Groups on the Support menu Stamps In Class Group Open to students educators and independent learners this forum allows members to ask each other questions and share answers as they work through the activities exercises and projects in this text Parallax Educator s Group This moderated forum provides support for educators and welcomes feedback as we continue to develop our Stamps in Class curriculum To join this group you must have proof of your status as an educator verified by Parallax The Teacher s Guide for this text is available as a free download through this forum Page vi What s a Microcontroller Educational Support stampsinclass parallax com Contact the Parallax Stamps in Class Team directly if you are having difficulty subscribing to either of these Yahoo Groups or have questions about the material in this text our Stamps in Class Curriculum our Educator s Courses or any of our educational services Educational Sales sales parallax com Contact our Sales Team for information about educa
203. ew months old you will probably have the most up to date material If it s an older CD consider requesting a new one from Parallax or downloading the files you need from the Parallax web site ACTIVITY 2 INSTALLING THE SOFTWARE By now you have either downloaded the BASIC Stamp Editor Installer from the Parallax web site or located it on the Parallax CD Now let s run the BASIC Stamp Editor Installer Installing the Software Step by Step y Ifyou downloaded the BASIC Stamp Editor Installer from the Internet click the Open button on the Download Complete window shown in Figure 1 16 Download complete isi ks yh Download Complete Saved Editor_v2 0_Beta_1_6MB exe from www parallax com Downloaded 6 01 MB in 5 sec Download to Setup_Stamp_Editor_v2 0_Beta_1_6MB exe Transfer rate 1 20 MB Sec Open Open Folder Close Chapter 1 Getting Started Page 11 Figure 1 16 Download Complete Window If you skipped here from the Downloading the Software from the Internet section click the Open button V Ifyou located the software on the Parallax CD click the Jnstall button shown in Figure 1 17 Figure 1 17 The Parallax CD Browser Install button located near bottom of window When the BASIC Stamp Editor InstallShield Wizard window opens click the Next button shown in Figure 1 18 tamp Editor v2 0 Beta 1 InstallShield Wizard Welcome to the InstallShield
204. examples from TakeMeOutToTheBallGame 2g 6 half note G dotted sixth octave a default quarter note duration A note played in the sixth octave g 6 quarter duration g note sharp denoted by sixth octave The character 1P stands for pause and it is used for rests With no extra information the p plays for the default quarter note duration You could also play a half note s worth of rest by using LA 2p Here is an example of a dotted rest LA 2p r In this case the rest would last for a half note plus a quarter note s duration Index 177 94 244 95 244 23 5 3 position switch 16 7 7 Segment Display 165 70 A Active High 79 Active Low 79 AD5220 Digital Potentiometer Pin Map 268 Pin Names and Functions 268 Algorithm 96 American Standard Code for Information Interchange 30 Amp 319 Anode 40 Array 292 ASCII 30 253 B Base 265 BASIC Stamp BASIC Stamp 2 Module 1 Components 307 HomeWork Board 305 Index Page 329 BASIC Stamp Editor Identification Window 19 Identify 316 317 Memory Map 263 Software 5 Trouble Shooting 315 BASIC Stamp HomeWork Board 14 BASIC Stamp Home Work Board Components 309 Battery 44 Beat 226 Bi Color LED 61 Binary Numbers 20 77 177 Bit 55 175 247 Board of Education 13 Components 308 Full Kit 303 Revision label 105 Servo Header 106 Board of Education Rev B Components
205. facturers also publish application notes which show how to use their integrated circuit in unique or useful ways that make it easier to design products The integrated circuit manufacturers give away this information in hopes that engineers will use it to build their chip onto the latest must have toy or appliance If thousands of toys are sold it means the company sells thousands of their integrated circuits In this chapter you will experiment with a transistor and a special purpose integrated circuit called a digital potentiometer As mentioned earlier the transistor is the basic building block for integrated circuits It s also a basic building block for lots of other circuits as well The digital potentiometer also has a variety of uses Keep in mind that for each activity you have done there are probably hundreds of different ways that you could use each of these integrated circuits Chapter 9 Electronic Building Blocks Page 265 ACTIVITY 1 CONTROL CURRENT FLOW WITH A TRANSISTOR In this activity you will use a transistor as a way to control the current passing through an LED You can use the LED to monitor the current since it glows more brightly when more current passes through it and less brightly when less current passes through it Introducing the Transistor Figure 9 2 shows the schematic symbol and part drawing of the 2N3904 transistor There are many different types of transistors This one is called NPN which refers to
206. firmly connected to both the computer s COM port and the DB9 connector on the Board of Education or BASIC Stamp HomeWork Board Make sure that your serial cable is a normal serial cable DO NOT USE A NULL MODEM CABLE Most null modem cables are labeled NULL or Null Modem visually inspect the cable for any such labeling If you find that label do not try to use it to program the BASIC Stamp Disable any palmtop communication software If you are using a BASIC Stamp and Board of Education also check the following Make sure the BASIC Stamp was inserted into the socket right side up aligning the reference notch as shown in Figure 1 28 on page 17 If you are using a DC power supply that plugs into the wall make sure it is plugged in to both the wall and the Board of Education Verify that the green Pwr light on the Board of Education emits light when the DC supply is plugged in Make sure the BASIC Stamp is firmly inserted into the socket Visually inspect the BASIC Stamp to make sure that none of the pins folded under the module instead of sinking into their sockets on the Board of Education Disconnect power first then press down firmly on the module with your thumb If your Identification Window looks similar to Figure E 1 it means that the BASIC Stamp Editor cannot find your BASIC Stamp on any COM port Note that the Loopback and Echo columns show No If you have this problem try the following Page 316 What s a Micr
207. ge 125 with this code block DO DEBUG Enter pulsout duration CR DEBUGIN DEC duration IF duration lt 500 THEN DEBUG Value of duration must be above 499 CR PAUSE 1000 ENDIF F duration gt 1000 THEN DEBUG Value of duration must be below 1001 CR PAUSE 1000 ENDIF LOOP UNTIL duration gt 499 AND duration lt 1001 H y Save the program V Run the program and verify that it rejects values outside the appropriate range for the servo ACTIVITY 3 CONVERTING POSITION TO MOTION In this activity you will program the servo to change position at different rates By changing position at different rates you will cause your servo horn to rotate at different speeds You can use this technique to make the servo control motion instead of position Programming a Rate of Change for Position You can use a FOR NEXT loop to make a servo sweep through its range of motion like this FOR counter 500 TO 1000 PULSOUT 14 counter PAUSE 20 NEXT The FOR NEXT loop causes the servo s horn to start at around 2 o clock and then rotate slowly counterclockwise until it gets to 10 o clock Because counter is the index of the FOR NEXT loop it increases by one each time through The value of counter is also used in the PULSOUT command s Duration argument which means the duration of each pulse gets a little longer each time through the loop Since the duration changes so does the position of the servo s horn FOR NEXT loops
208. ges in air pressure just as a guitar string does As with the guitar string your ear detects the changes in air pressure caused by the piezoelectric speaker and it typically sounds like a beep or a tone Programming Speaker Control The FREQOUT command is a convenient way of sending high low signals to a speaker to make sound The BASIC Stamp Manual shows the command syntax as this FREQOUT Pin Duration Freq1 Freq2 As with most of the other commands used in this book Pin is a value you can use to choose which BASIC Stamp I O pin to use The Duration argument is a value that tells the FREQOUT command how long the tone should play in milliseconds The Freq1 argument is used to set the frequency of the tone in Hertz There is an optional Freg2 argument that can be used to mix frequencies Here is how to send a tone to I O pin P9 that lasts for 1 5 seconds and has a frequency of 2 kHz FREQOUT 9 1500 2000 Example Program TestPiezoWithFreqout bs2 This example program sends the 2 kHz tone to the speaker on I O pin P9 for 1 5 seconds You can use the Debug terminal to see when the speaker should be beeping and when it should stop V Enter and run TestPiezoWithFreqout bs2 y Verify that the speaker makes a clearly audible tone during the time that the Debug Terminal displays the message Tone sending What s a Microcontroller TestPiezoWithFreqout bs2 Send a tone to the piezo speaker using the FREQOUT command SSTAM
209. ges the LED circuit s supply from Vdd to Vss Second while a human can make that change several times a minute the BASIC Stamp can do it thousands of times per second LED Test Circuit Parts Same as Activity 1 Connecting the LED Circuit to the BASIC Stamp The LED circuit shown in Figure 2 11 is wired almost the same as the circuit in the previous exercise The difference is that the resistor s lead that was manually switched between Vdd and Vss is now plugged into a BASIC Stamp I O pin Disconnect power from your Board of Education or HomeWork Board y Modify the circuit you were working with in Activity 1 so that it matches Figure 2 11 Page 48 What s a Microcontroller Vdd Vin ps P14 a Figure 2 11 4709 BASIC Stamp X LED BL f E pE Controlled LED P13 Circuit P12 Wee oH The LED circuit s P9 input is now B7 connected to a P6 BASIC Stamp I O r3 pin instead of Vdd B3 or Vss P2 P1 PO X2 so Resistors are essential Always remember to use a resistor Without it too much current will flow through the circuit and it could damage any number of parts in your circuit BASIC wy Stamp or Board of Education or HomeWork Board Turning the LED On Off with a Program The example program makes the
210. get your card A store cash register beeps to let the teller know that the bar code of the grocery item passed over the scanner was read Many calculators beep when the wrong keys are pressed Let s not forget that you may have started your day with a beeping alarm clock MICROCONTROLLERS SPEAKERS BEEPS AND ON OFF SIGNALS Just about all of the electronic beeps you hear during your daily routine are made by microcontrollers connected to speakers The microcontroller creates these beeps by sending rapid high low signals to various types of speakers The rate of these high low signals is called the frequency and it determines the tone or pitch of the beep Each time a high low repeats itself it is called a cycle You will often see the number of cycles per second referred to as Hertz and it is abbreviated Hz For example one of the most common frequencies for the beeps that help machines get your attention is 2 kHz That means that the high low signals repeat at 2000 times per second Introducing the Piezoelectric Speaker In this activity you will experiment with sending a variety of signals to a common small and inexpensive speaker called a piezoelectric speaker Its schematic symbol and part drawing are shown in Figure 8 1 Figure 8 1 Piezoelectric Speaker Schematic Symbol and Me Part Drawing TH Page 220 What s a Microcontroller i j A piezoelectric speaker is commonly referred to as a piezo speaker or piezo buz
211. gment emits light What s the x with the nc above it in the schematic The nc stands for not connected or 9 no connect It indicates that a particular pin on the 7 segment LED display is not connected to anything The x at the end of the pin also means not connected Schematics sometimes use just the x or just the nc Page 168 What s a Microcontroller Vdd 1kQ nc nc nc nc nc nc nc Figure 6 4 Test Circuit Schematic for the A Segment LED Display Vss ne Figure 6 5 Test Circuit Wiring Diagram for the A Segment LED Display V Disconnect power and modify the circuit by connecting the resistor to the B LED input as shown in Figure 6 6 and Figure 6 7 Chapter 6 Digital Display Page 169 Vdd 1kQ Figure 6 6 Test Circuit Schematic for the B Segment LED Display T nc Figure 6 7 Test Circuit Wiring Diagram for the B Segment LED Display V Reconnect power and verify that the B segment emits light V Using the pin map from Figure 6 2 as a guide repeat these steps for segments C through G Your Turn The Letter A and the Number Two Figure 6 8
212. gulator This chip takes the battery voltage and converts it to almost exactly 5 0 V which is what the rest of the components on the BASIC Stamp need to run properly The upper left chip is the BASIC Stamp module s EEPROM PBASIC programs are condensed to numbers called tokens that are downloaded to the BASIC Stamp These tokens are stored in the EEPROM and you can view them by clicking Run and then Memory Map in the BASIC Stamp Editor The largest chip is called the Interpreter chip It fetches the tokens from the EEPROM and then interprets the PBASIC command that the token represents Then it executes the command fetches the next token and so on This process is called fetch and execute 5 V regulator accepts an input voltage 2 K EEPROM ere retains your PBASIC source code even with power loss Figure 9 1 Integrated Circuits on the BASIC Stamp _ s a TAAR pen EP sii it ly PBASIC interpreter executes your program at 4 000 instructions second Page 264 What s a Microcontroller People use the term integrated circuit IC to talk about little black chips The integrated circuit is actually a tiny silicon chip that s contained inside the black plastic or ceramic case Depending on the chip it may have anywhere between hundreds and millions of transistors A transistor is the basic building block for integrated circuits and you will have the opportunity to experiment wit
213. h a transistor in this chapter Other familiar components that are designed into silicon chips include diodes resistors and capacitors Take a moment to think about the activities you ve tried in this book so far The list includes switching LEDs on and off reading pushbuttons controlling servos reading potentiometers measuring light controlling displays and making sounds Even though that s just the beginning it s still pretty impressive especially considering that you can combine these activities to make more complex gizmos and gadgets The core of the system that made all those activities possible is comprised of just the three integrated circuits shown in Figure 9 1 and a few other parts It just goes to show how powerful integrated circuits can be when they are designed to work together EXPAND YOUR PROJECTS WITH PERIPHERAL INTEGRATED CIRCUITS There are thousands of integrated circuits designed to be used with microcontrollers Sometimes different integrated circuit manufacturers make chips that perform the same function Sometimes each chip s features differ slightly and other times the chips are identical but one might cost a little less than the other Each one of the thousands of different integrated circuits can be used as a building block for a variety of designs Companies publish information on how each of their integrated circuits work in documents called datasheets that are published on the World Wide Web These manu
214. hat the BASIC Stamp gets reliable measurements from the potentiometer V Correct any problems you catch before moving on to the next circuit What s a Microcontroller ReadPotWithRcTime bs2 Read potentiometer in RC time circuit using RCTIME command SSTAMP BS2 SPBASIC 2 5 time VAR Word DO HIGH 7 PAUSE 100 RCTIME 7 1 time DEBUG HOME time DECS time LOOP Your Turn Building and Testing the Photoresistor Circuit Once the first RC time circuit has been built and tested the process can be repeated for the second RC time circuit yV Add the photoresistor circuit shown in Figure 10 5 to your project on the breadboard V Modify ReadPotWithRcTime bs2 so the photoresistor is connected to P9 V Correct any problems you catch before moving on to the next activity Chapter 10 Running the Whole Show Page 287 Figure 10 5 Adding the Photoresistor Circuit Sig op P9 Hi TN 7 D4 J ajm 220 Q ky d woofs J W p a L F 0 1 uF 4 ak P9 S Beg NG ow l nS Angy 5 g no RE jooe sooyo PA ofA os L 3 donnen Vss Sha ooog sooco F p s e 000 oomo ACTIVITY 3 SUBSYSTEM INTEGRATION EXAMPLE Now that all the elements in the sensor array are built and tested you can now write a program that makes use of all f
215. have one of the following Parallax hardware options Option 1 e Board of Education Full Kit 28102 AND e What s a Microcontroller Parts Kit 28152 with text 28122 without text These two kits are also sold separately The Board of Education Full Kit contents listed below is the core equipment of the Stamps in Class curriculum and it can be used with any of the Stamps in Class texts and kits Board of Education Full Kit 28102 Parts and quantities subject to change without notice Parallax Part Description Quantity 550 00022 Board of Education 1 800 00016 Pluggable wires 10 BS2 IC BASIC Stamp 2 module 1 800 00003 Serial cable 1 750 00008 DC power supply 9 V 300 mA 1 27000 Parallax CD includes software 1 700 00037 Rubber feet set of 4 1 You may purchase the What s a Microcontroller Parts Kit alone 28122 or with the parts and the What s a Microcontroller printed text together 28152 These parts kits are assembled to support the activities and projects in the current printed version of the text The What s a Microcontroller Parts Kit contents are listed in the table on the following page Page 304 What s a Microcontroller What s a Microcontroller Parts Kit 28122 What s a Microcontroller Parts amp Text 28152 Parts and quantities subject to change without notice
216. he BASIC Stamp when power input drops below a safe level Communication circuit makes programming pins compatible Power input pins for Pins for with serial port 6 12 VDG rn ground programming and debugging through a Reset pin for quick serial port shut down restart 2K EEPROM 5V regulator converts retains your input power from PBASIC source 6 12 VDC to 5 VDC code even with power loss Alternate positive power input pin for regulated VDC 2 zs el Filter capacitor for 5 V regulator 20 MHz resonator provides a clock E onl EN source for the al interpreter W O pins 0 7 W O pins 8 15 for general E e for general purpose purpose I O Sar I O control control Fa z a PBASIC interpreter executes your program at 4 000 instructions per second Figure C 1 Parallax Inc s BASIC Stamp 2 Microcontroller Module Components and their Functions Page 308 What s a Microcontroller The Board of Education Rev C Parallax Inc s Board of Education Rev C carrier board is shown in Figure C 2 Its major components and their functions are indicated by labels Voltage regulator supplies Board of Education i i with regulated 5 VDC Vdd and ground Vss Soda reguisted 5 VDC Vin connects directly to the Application Module AppMod Board of Education s power source connector for add on modules 4 RIC servo connection Power jack 2 1 mm center positive 6 9 VDC lt ports for robotic project
217. he DATA directives that stores musical notes and durations for the next example program When played it should resemble the song Frere Jacques Only the note characters are stored in the Notes DATA directive because LOOKUP and LOOKDOWN commands will be used to match up letters to their corresponding frequencies Notes DATA WEN TDI TER NE MOIM ADU UE ECI TURD URE y ugu A E k pn A G NOT Durations DATA 4 4 4 4 4 4 4 4 4 4 Page 234 What s a Microcontroller WholeNote CON 2000 The first number in the Durations DATA directive tells the program how long the first note in the Notes Data directive should last The second duration is for the second note and so on The durations are no longer in terms of milliseconds Instead they are much smaller numbers that can be stored in bytes so there is no Word prefix in the DATA directive Compared to storing values in terms of milliseconds these numbers are more closely related to sheet music Here is a list of what each duration means e 1 whole note e 2 halfnote e 4 quarter note e 8 eighth note e 16 sixteenth note e 32 thirty second note After each value is read from the Durations DATA directive it is divided into the WholeNote value to get the Duration used in the FREQOUT command The amount of time each note lasts depends on the tempo of the song A faster tempo means each note lasts for less time while a slower tempo means each note lasts longer Sin
218. he Programming Potentiometer Control of the Servo section on page 154 using your maximum and minimum values Chapter 5 Measuring Rotation Page 157 Substitute your scale and offset values in ControlServoWithPot bs2 Add this line of code between the PpuLsouT and Loop commands so that you can view your results A DEBUG HOME DEC5 time Display adjusted time value V Run the modified program and check your work Because the values were rounded off the limits may not be exactly 500 and 1000 but they should be pretty close Using Constants in Programs In larger programs you may end up using the PULSOUT command and the value of the scale factor which was 185 and the offset which was 500 many times in the program You can use alias names for these values with the con directive like this scaleFactor CON 185 offset CON 500 e These alias names are just about always declared near the beginning of the program so lt that they are easy to find Now anywhere in your program that you want to use one of these values you can use the words offset or scaleFactor instead For example time time scaleFactor Scale by 0 724 time time offset Offset by 500 You can also apply the same technique with the I O pins For example you can declare a constant for I O pin P7 rePin CON 7 There are two places in the previous example program where the number 7 is used to refer to I O pin P7 The first can now be
219. he two outer terminals adjustable 3 How is a capacitor like a rechargeable battery How is it different 4 What can you do with an RC time circuit to give you an indication of the value of a variable resistor 5 What happens to the RC discharge time as the value of R the resistor gets larger or smaller 6 What does the con directive do Explain this in terms of a name and a number Exercise 1 Let s say that you have a 0 5 UF capacitor in an RC timer circuit and you want the measurement to take 10 times as long Calculate the value of the new capacitor Projects 1 Add a bi color LED circuit to Activity 4 Modify the example program so that the bi color LED is red when the servo is rotating counterclockwise green when the servo is rotating clockwise and off when the servo holding its position 2 Use IF THEN to modify the example program from Activity 4 so that the servo only rotates between PULSOUT values of 650 and 850 Solutions Q1 A potentiometer Page 162 What s a Microcontroller Q2 Q3 Q4 Q5 Q6 El Pl No it s fixed The variable resistance is between either outer terminal and the wiper middle terminal A capacitor is like a rechargeable battery in that it can be charged up to hold voltage The difference is that it only holds a charge for a very small amount of time You can measure the time it takes for the capacitor to discharge or charge This time is related to the resistance and capa
220. hm An algorithm is a sequence of mathematical operations What s pseudo random Pseudo random means that it seems random but it isn t really 9 Each time you start the program over again you will get the same sequence of values w What s a seed A seed is a value that is used to start the pseudo random sequence If you use a different value change value from 23 to some other number you will get a different pseudo random sequence Item 3 A player that lets go of the button before the light turns green gets an unreasonably good score 1 ms Your microcontroller needs to figure out if a player is cheating Pseudo code was introduced near the end of Activity 3 in this chapter Here is some pseudo code to help you apply an IF THEN ELSE statement to solve the problem e If the value of timeCounter equals 1 o Display a message telling the player he or she has to wait until after the light turns green to let go of the button e Else if the value of timeCounter is greater than 1 o Display the value of timeCounter just like in ReactionTimer bs2 time in ms y Modify your program by implementing this pseudo code in PBASIC to fix the cheating player problem Chapter 3 Digital Input Pushbuttons Page 97 SUMMARY This chapter introduced the pushbutton and common pushbutton circuits This chapter also introduced how to build and test a pushbutton circuit and how to use the BASIC Stamp to read the state of one or
221. how the BASIC Stamp can be used to monitor a potentiometer circuit and control the position of a servo Chapter 5 Measuring Rotation Page 153 An example of a model airplane and its radio controller are shown in Figure 5 13 The model airplane has servos to control all its flaps and the gas engine s throttle settings These servos are controlled using the radio control RC unit in front of the plane This RC unit has potentiometers under a pair of joysticks that are used to control the servos that in turn control the plane s elevator and rudder flaps Figure 5 13 Model Airplane and Radio Controller How the RC Unit Controls the Airplane The potentiometers under the joysticks are monitored by a circuit that converts the position of the joystick into control pulses for the servo These control pulses are then converted to radio signals and transmitted by the handheld controller to a radio receiver in the model airplane The radio receiver converts these signals back to control pulses which then position the servos Potentiometer Controlled Servo Parts 1 Potentiometer 10 kQ 1 Resistor 220 Q red red brown 1 Capacitor 0 1 uF 1 Parallax Standard Servo 1 LED any color 2 Jumper wires HomeWork Board users will also need 1 3 pin male male header Page 154 What s a Microcontroller 4 Jumper wires CAUTION use only a Parallax Standard Servo for the activities in this text
222. i color LED Make the bi color LED start out red for 3 seconds After 3 seconds change the bi color LED to green When the bi color LED changes to green flash the yellow LED on and off once every second for ten seconds When the yellow LED is done flashing the bi color LED should switch back to red and stay that way Solutions Q1 Omega refers to the ohm which measures how strongly something resists current flow Q2 A 470 Q resistor higher values resist more strongly than lower values therefore lower values allow more current to flow Q3 To connect 2 wires plug the 2 wires into the same row of 5 sockets You can connect 4 wires by plugging all 4 wires into the same row of 5 sockets Q4 Disconnect the power Q5 10 seconds Q6 PAUSE 60000 Q7 Bit Nib Byte and Word Chapter 2 Lights On Lights Off Page 69 Q8 No The largest value a byte can hold is 255 The value 500 is out of range for a byte Q9 HIGH 7 will cause the BASIC Stamp to internally connect I O pin P7 to Vdd El The PAUSE Duration must be reduced to 500ms 4 125ms To use I O pin P13 HIGH 14 and Low 14 have been replaced with HIGH 13 and Low 13 P13 DO 470 Q HIGH 13 PAUSE 125 LOW 13 PAUSE 125 Vss LOOP E2 The counter variable has to be changed to Word size and the For statement has to be modified to count from 1 to 5000 counter VAR Word FOR counter 1 to 5000 DEBUG counter CR HIGH 14 PAUSE 500 LOW 14 PAUSE 500 NEXT P1
223. ices and machinery working through the activities and projects in the following Student Guides is highly recommended Preface Page vii Applied Sensors Student Guide Version 1 3 Parallax Inc 2003 Basic Analog and Digital Student Guide Version 1 3 Parallax Inc 2004 Industrial Control Student Guide Version 1 1 Parallax Inc 1999 Robotics with the Boe Bot Student Guide Version 2 0 Parallax Inc 2003 More Robotics Kits Some enter the Stamps in Class curriculum through the Robotics with the Boe Bot Student Guide After completing it you will be ready for either or both of these more advanced robotics texts and kits Advanced Robotics with the Toddler Student Guide Version 1 2 Parallax Inc 2003 SumoBot Manual Version 2 0 Parallax Inc 2004 Educational Project Kits Elements of Digital Logic Understanding Signals and Experiments with Renewable Energy focus more closely on topics in electronics while StampWorks provides a variety of projects that are useful to hobbyists inventors and product designers interested in trying a variety of projects Elements of Digital Logic Student Guide Version 1 0 Parallax Inc 2003 Experiments with Renewable Energy Student Guide Version 1 0 Parallax Inc 2004 Stamp Works Manual Version 1 2 Parallax Inc 2001 Understanding Signals Student Guide Version 1 0 Parallax Inc 2003 Reference This book
224. ing a What s a Microcontroller kit that somebody used before you the LED may be damaged so try a different one y If you are in a lab class check with your instructor Still stuck If you don t have an instructor or friend who can help you can always check __ with the Stamps in Class discussion group The first pages of this book has Internet Access J information on where to find the Stamps in Class discussion group If the group is unable to help you solve the problem you can contact the Parallax Technical Support department by following the Support link at www parallax com How the LED Test Circuit Works The Vdd and Vss terminals supply electrical pressure in the same way that a battery would The Vdd sockets are like the battery s positive terminal and the Vss sockets are like the battery s negative terminal Figure 2 7 shows how applying electrical pressure to a circuit using a battery causes electrons to flow through it This flow of electrons is called electric current or often just current Electric current is limited by the resistor This current is what causes the diode to emit light Figure 2 7 LED On Circuit Electron Flow The minus signs with the circles around them are used to show electrons flowing from the battery s negative terminal to its positive terminal Chapter 2 Lights On Lights Off Page 45 Chemical reactions inside the battery supply the circuit with current
225. instead of from 0 to 6 y Modify TwinkleTwinkle bs2 so that it plays the first two phrases of the song instead of just the first phrase ACTIVITY 4 MICROCONTROLLER MUSIC Note durations are not recorded on sheet music in terms of milliseconds Instead they are described as whole half quarter eight sixteenth and thirty second notes As the name suggests a half note lasts half as long as a whole note A quarter note lasts one fourth the time a whole note lasts and so on How long is a whole note It depends on the piece of music being played One piece might be played at a tempo that causes a whole note to last for four seconds another piece might have a two second whole note and yet another might have some other duration Rests are the time between notes when no tones are played Rest durations are also measured as whole half quarter eighth sixteenth and thirty second A Better System for Storing and Retrieving Music You can write programs that store twice as much music in your BASIC Stamp by using bytes instead of words in your DATA directives You can also modify your program to make the musical notes easier to read by using some of the more common musical conventions for notes and duration This activity will start by introducing how to store musical information in a way that relates to the concepts of notes durations and rests Tempo is also introduced and it will be revisited in the next activity Here is an example of t
226. iode LED indicator light on and off LED indicators are useful in a variety of places including many computer monitors disk drives and other devices The LED was introduced along with a technique to identify its anode and cathode terminals An LED circuit must have a resistor to limit the current passing through it Resistors were introduced along with one of the more common coding schemes you can use to figure out a resistor s value The BASIC Stamp switches an LED circuit on and off by internally connecting an I O pin to either Vdd or Vss The HIGH command can be used to make the BASIC Stamp internally connect one of its I O pins to Vdd and the Low command can be used to internally connect an I O pin to Vss The PAUSE command is used to cause the BASIC Stamp to not execute commands for an amount of time This was used to make LEDs stay on and or off for certain amounts of time This amount of time is determined by the number used in the PAUSE command s Duration argument The bDo LooP can be used to create an infinite loop The commands between the Do and Loop keywords will execute over and over again Even though this is called an infinite loop the program can still be re started by disconnecting and reconnecting power or pressing and releasing the Reset button A new program can also be downloaded to the BASIC Stamp and this will erase the program with the infinite loop Current direction and voltage polarity were introduced using a bi
227. ion from ReusablePasswordChecker bs2 and paste it after the end of the last subroutine in PasswordedSensorTerminal bs2 V Test PasswordedSensorTerminal bs2 and see if it works debug as needed Chapter 10 Running the Whole Show Page 297 SUMMARY This chapter introduced the technique of individually testing each circuit subsystem before integrating it into a larger system This chapter also introduced the oN cosuB command which is particularly useful for menu systems The useful PIN directive was demonstrated as a way to name your I O pins and then let the BASIC Stamp Editor figure out whether to read an input or write to an output A password program was used to introduce variable arrays the EXIT command and the DEBUGIN command s STR formatter The password program was then integrated into a larger sensor terminal program to give it more functionality Questions 1 When should you test subsystems individually before trying to make them work together Why 2 How many programs did you use in this chapter that were from other chapters 3 How does the PIN directive differ from the con and var directives 4 What s the difference between EXIT and END Exercises 1 Describe the general 3 step process you would use to add a piezospeaker circuit to your project 2 Modify PasswordChecker bs2 from page 293 so that the message you entered appears in the Debug Terminal along with the text of the password Projects 1 Add
228. ionTones bs2 ActionTones bs2 demonstrates a few different combinations of pause duration and frequency The first sequence of tones sounds similar to an electronic alarm clock The second one sounds similar to something a familiar science fiction movie robot might say The third is more the kind of sound effect you might hear in an old video game y Enter and run ActionTones bs2 What s a Microcontroller ActionTones bs2 Demonstrate how different combinations of pause duration and frequency can be used to make sound effects SSTAMP BS2 SPBASIC 2 5 duration VAR Word frequency VAR Word DEBUG Alarm CR PAUSE 100 FREQOUT 9 500 1500 PAUSE 500 FREQOUT 9 500 1500 PAUSE 500 FREQOUT 9 500 1500 PAUSE 500 FREQOUT 9 500 1500 PAUSE 500 IDIHEWC VRtolooie me PIVARE ECR PAUSE 100 FREQOUT 9 100 2800 FREQOUT 9 200 2400 FREQOUT 9 140 4200 FREQOUT 9 30 2000 PAUSE 500 DEBUG Hyperspace CK PAUSE 100 FOR duration 15 TO 1 STEP 1 FOR frequency 2000 TO 2500 STEP 20 FREQOUT 9 duration frequency NEXT NEXT DEBUG Done CR END How ActionTones bs2 Works Chapter 8 Frequency and Sound Page 223 The Alarm routine sounds like an alarm clock This routine plays tones at a fixed frequency of 1 5 kHz for a duration of 0 5 s with a fixed delay between tones of 0 5 s The Robot reply routine uses various frequencies for brief durations The Hyperspace routine u
229. is a part drawing used in some beginner level Stamps in Class texts to help you identify the resistor in your kit Chapter 2 Lights On Lights Off Page 39 Gold Figure 2 2 Siver 470 Q Resistor Part W Fr Blank Drawing 470 Q 4 Yellow TR Brown Schematic symbol left and Part Drawing right Resistors like the ones we are using in this activity have colored stripes that tell you what their resistance values are There is a different color combination for each resistance value For example the color code for the 470 Q resistor is yellow violet brown There may be a fourth stripe that indicates the resistor s tolerance Tolerance is measured in percent and it tells how far off the part s true resistance might be from the labeled resistance The fourth stripe could be gold 5 silver 10 or no stripe 20 For the activities in this book a resistor s tolerance does not matter but its value does Each color bar that tells you the resistor s value corresponds to a digit and these colors digits are listed in Table 2 1 Figure 2 3 shows how to use each color bar with the table to determine the value of a resistor Table 2 1 Resistor Color Code Values Digit Color 0 Black lich Figure 2 3 2 Red S N Resistor Color 3 Orange 7 Codes First Digit Number of Zeros 4 Yellow o 5 Green Second Digit 6 Blue 7 Violet 8 Gray 9 White Here is an example that show
230. is an essential reference for all Stamps in Class Student Guides It is packed with information on the BASIC Stamp series of microcontroller modules our BASIC Stamp Editor and our PBASIC programming language BASIC Stamp Manual Version 2 0c Parallax Inc 2000 Page viii What s a Microcontroller FOREIGN TRANSLATIONS Parallax educational texts may be translated to other languages with our permission e mail stampsinclass parallax com If you plan on doing any translations please contact us so we can provide the correctly formatted MS Word documents images etc We also maintain a discussion group for Parallax translators that you may join It s called the Parallax Translators Yahoo group and directions for finding it are included on the inside cover of this text See section entitled WEB SITE AND DISCUSSION LISTS after the Title page SPECIAL CONTRIBUTORS The Parallax team assembled to write this text includes curriculum design and technical writing by Andy Lindsay illustration by Rich Allred cover design by Jen Jacobs and Larissa Crittenden general consulting by Aristides Alvarez and Jeff Martin electromechanical consulting by John Barrowman technical review and solutions by Kris Magri technical editing by Stephanie Lindsay and committee review by Rich Allred Gabe Duran Stephanie Lindsay and Kris Magri What s a Microcontroller Student Guide Version 2 2 was written by Andy Lindsay after collecting observati
231. ithout any adjustments to Stamp Plot Lite s display settings DEBUG AMAX 1250 CR ITMAX 25 CR TMIN 0 CR SHFT ON CR RSET CR gt For more information on how to send values and control codes to Stamp Plot Lite run J Stamp Pot Lite s Help file Click Start select programs select Stamp Plot then click Stamp News Plot Help Example Program PlotPhotoresistor bs2 Follow these steps to plot the photoresistor data 7 V Use the BASIC Stamp Editor to enter and run PlotPhotoresistor bs2 y Verify that there is a single column of values scrolling down the Debug Terminal Figure 7 5 shows an example y Debug Terminal 1 Com Port Bau 36 rok com ose Data Bits Flow Control o_o Figure 7 5 Example of Scrolling Values in the Debug Terminal y Make a note of the COM number in the COM Port field in the upper left hand corner of the Debug Terminal y Use the Windows Start Menu to run Stamp Plot Lite Click Start then select Programs Stamp Plot Stamp Plot Lite y Set the COM Port field in Stamp Plot Lite to that same value Figure 7 6 shows an example where the value is COM1 in the Debug Terminal so Stamp Plot is also set to COM1 Your COM port value may be a different number Page 196 What s a Microcontroller Just check to see what the number is in the Debug Terminal then set Stamp Plot Lite to that number y Close the Debug Terminal click the X button on the top right or
232. ity not to wy work or even permanently damage the servo For best results make sure your battery is new If you are using a rechargeable battery make sure it is freshly recharged It should also be rated for 100 mAh milliamp hours or more See Appendix D Batteries and Power Supplies for more information Page 112 What s a Microcontroller P14 470 Q Figure 4 12 Vin Schematic for Servo and LED Indicator on Board of Education Rev B V Disconnect your battery or any other power supply from your board y Build the LED circuit shown in Figure 4 12 V Connect the servo to the servo header as shown in Figure 4 13 Chapter 4 Controlling Motion Page 113 Figure 4 13 Connecting Servo to Servo Header on the Board of Education Rev B PARALLAX www parallax com Make sure that the colors on the servo s cable align properly with the colors labeled in the picture y Connect a 9 V battery to Board of Education Rev B The servo may move a little bit when you make the connection Programming Servo Control A servo is controlled by very brief high signals These high signals are sent over and over again every 20 ms The high signals last anywhere between 1 and 2 ms The PULSOUT command can be used to send a pulse
233. k sockets along the top and along the left The black sockets along the top have labels above them Vdd Vin and Vss These are called the power terminals and they will be used to supply your circuits with electricity The black sockets on the left have labels like PO P1 up through P15 These are sockets that you can use to connect your circuit to the BASIC Stamp module s input output pins The white board with lots of holes in it is called a solderless breadboard You will use this breadboard to connect components to each other and build circuits Page 42 What s a Microcontroller Vdd Vin Vss x3 POHA OLA a a OLA 7 P13 P HO Figure 2 5 a POLA i P12 HHHH P Prototyping Area P10 POH B a B e P9 i Power terminals black eS ii HH sockets along top I O pin P6 z z z z 5 t access black sockets along P5 ii KKH the side and solderless P4 i P3 eH eH breadboard white sockets P2 CHO CHO BI CHO CHO PO CHO CHH XO HHHH CHH HHO 4 __ Input output pins are usually called I O pins and after connecting your circuit to one or J more of these I O pins you can program your BASIC Stamp to monitor the circuit input or w sendon or off signals to the circuit output You will try this in the next activity Figure 2 6 shows a circuit schematic and a picture of how that circuit will look when it is
234. ler or does it contain one What clues would you look for to figure out whether or not an appliance like a clock radio or a cell phone contains a microcontroller 4 What does an apostrophe at the beginning of a line of PBASIC program code signify 5 What PBASIC commands did you learn in this chapter 6 Let s say you want to take a break from your BASIC Stamp project to go get a snack or maybe you want to take a longer break and return to the project in a couple days What should you always do before you take your break Exercises Explain what the asterisk does in this command DEBUG DEC 7 11 Page 34 What s a Microcontroller Guess what the Debug Terminal would display if you ran this command DEBUG DEC 7 11 3 There is a problem with these two commands When you run the code the numbers they display are stuck together so that it looks like one large number instead of two small ones Modify these two commands so that the answers appear on different lines in the Debug Terminal DEBUG DEC 7 11 DEBUG DEC 7 11 Projects 1 Use DEBUG to display the solution to the math problem 1 2 3 4 Which lines can you delete in FirstProgramYourTurm bs2 if you place the command shown below on the line just before the END command in the program Test your hypothesis your prediction of what will happen Make sure to save FirstProgram Y ourTurn bs2 with a new name like FirstProgramCh01Project05 bs2 Then make your modifica
235. lers capable of delivering the high low signals Some of these motors require lots of circuitry to help the microcontroller make them work Other motors require extra mechanical parts to make them work right in machines Of all the different types of motors to start with the hobby servo that you will experiment with in this chapter is probably the simplest As you will soon see it is easy to control with the BASIC Stamp requires little or no additional circuitry and has a mechanical output that is easy to connect to things to make them move ACTIVITY 1 CONNECTING AND TESTING THE SERVO In this activity you will connect a servo to a power supply and the BASIC Stamp You will then verify that the servo is functioning properly by programming the BASIC Stamp to send signals to the servo that will control the servo s position Introducing the Servo Figure 4 1 shows a drawing of a Parallax Standard Servo The plug 1 is used to connect the servo to a power source Vdd and Vss and a signal source a BASIC Stamp I O pin The cable 2 conducts Vdd Vss and the signal line from the plug into the servo The horn 3 is the part of the servo that looks like a four pointed star When the servo is running the horn is the moving part that the BASIC Stamp controls The case 4 Page 104 What s a Microcontroller contains the servo s control circuits a DC motor and gears These parts work together to take high low signals from the BASIC Stam
236. lock position The second FOR NEXT loop delivers 150 pulses but this time each pulse only lasts 1 0 ms This instructs the servo to turn to the 2 o clock position for about 3 15 seconds FOR COUNTER 1 TO 150 PULSOUT 14 500 PAUSE 20 NEXT fe 1 PULSOUT 14 500 sends a pulse that lasts 500 x 2 us That s 1000 us or 1 ms Figure 4 15 shows the timing diagram for this pulse train The pauses between pulses still last 20 ms Chapter 4 Controlling Motion Page 117 Figure 4 16 Timing Diagram for 1 0 Vdd 5 V ms Pulses Every 20 ms Servo horn in 2 o clock position Vss 0 V k 20ms _ gt The last ForR NEXT loop delivers 150 pulses each of which lasts 1 5 ms This instructs the servo to go to its center position 12 o clock for about 3 23 seconds FOR counter 1 TO 150 PULSOUT 14 750 PAUSE 20 NEXT fe i PULSOUT 14 750 sends a pulse that lasts 750 x 2 us That s 1500 us or 1 5 ms Figure 4 17 shows the timing diagram for these pulses While the low time is still 20 ms the pulse now lasts for 1 5 ms Figure 4 17 Timing Diagram for 1 5 ms Pulses Every Vdd 5 V 20 ms Servo horn is in 12 o clock position Vss 0 V 20ms _ gt Do the Math If you want to convert time from milliseconds to a Duration you can use for PULSOUT use this equation Duration number of ms x 500 Page 118 What s a
237. low 1 LED any color Page 266 What s a Microcontroller 1 Potentiometer 10 kQ 3 Jumper wires Building and Testing the Transistor Circuit Figure 9 3 shows a circuit that you can use to manually control how much current the transistor allows through the LED By twisting the knob on the potentiometer the circuit will deliver different amounts of current to the transistor s base This will cause a change in the amount of current the transistor allows to pass from its collector to its emitter The LED will give you a clear indication of the change by glowing more or less brightly N y Vdd POT 10 KQ Vss Build the circuit shown in Figure 9 3 Turn the knob on the potentiometer and verify that the LED changes brightness in response to a change in the position of the potentiometer s wiper terminal Vdd LED P15 P14 P13 P12 P11 P10 P9 P8 P7 P6 P5 P4 P3 P2 P1 X2 Your Turn Switching the Transistor On Off Figure 9 3 Manual Potentiometer Controlled Transistor Circuit If all you want to do is switch a transistor on and off you can use the circuit shown in Figure 9 4 When the BASIC Stamp sends a high signal to this circuit it will make it so that the transistor conducts as m
238. low N Vss Current LED The and signs show voltage applied to the circuit and the arrow shows current flow Voltage through the circuit A schematic drawing like Figure 2 8 is a picture that explains how one or more circuits are connected Schematics are used by students electronics hobbyists electricians engineers and just about everybody else who works with circuits Appendix F More about Electricity This appendix contains some glossary terms and an activity you can try to get more familiar with measurements of voltage current and resistance Page 46 What s a Microcontroller Your Turn Modifying the LED Test Circuit In the next activity you will program the BASIC Stamp to turn the LED on then off then on again The BASIC Stamp will do this by switching the LED circuit between two different connections Vdd and Vss You just finished working with the circuit where the resistor is connected to Vdd and the LED emits light Make the changes shown in Figure 2 9 to verify that the LED will turn off not emit light when the resistor s lead is disconnected from Vdd and connected to Vss V Disconnect power from your Board of Education or HomeWork Board y Unplug the resistor lead that s plugged into the Vdd socket and plug it into a socket labeled Vss as shown in Figure 2 9 V Reconnect power to your Board of Education or HomeWork Board y Check to make sure your green LED is not emitting light It
239. m Tec sn E Def Data C Unused Chapter 7 Measuring Light Page 199 2048 bytes 2 KB You can use 2048 bytes to store 2048 different numbers each of which can store a value between 0 and 255 The upper case B stands for bytes A lower case b stands for bits This can make a big em difference because 2048 Kb means that 2048 different numbers but each number is limited i to a value of either 0 or 1 w Although both the upper case K and the lower case k are called kilo they are slightly different The upper case K is used to indicate a binary kilobyte which is 1 x 2 1024 When referring to exactly 2000 bytes you can use the lower case k which stands for kilo 1X 10 1000 in the metric system Using the EEPROM for data storage can be very useful for remote applications One example of a remote application would be a temperature monitor placed in a truck that hauls frozen food A second example is a weather monitoring station One of the pieces of data a weather station might store for later retrieval is light levels Since we are using a photoresistor to measure light levels this activity introduces a technique for storing measured light levels to and retrieving them back from the EEPROM In this activity you will run one PBASIC example program that stores a series of light measurements in the BASIC Stamp module s EEPROM After that program is finished you will run a
240. mand followed by a number with no formatter the BASIC Stamp will read that number as an ASCII code Programming with ASCII Code ASCII is short for American Standard Code for Information Interchange Most microcontrollers and PC computers use this code to assign a number to each keyboard function Some numbers correspond to keyboard actions such as cursor up cursor down space and delete Other numbers correspond to printed characters and symbols The numbers 32 through 126 correspond to those characters and symbols that the BASIC Stamp can display in the Debug Terminal The following program will use ACSII code to display the words BASIC Stamp 2 in the Debug Terminal Example Program ASCIIName bs2 V Enter and run ASCIIName bs2 Remember to use the toolbar icons to place Compiler Directives into your programs SSTAMP BS2 Use the diagonal green electronic chip icon a SPBASIC 2 5 Use the gear icon labeled 2 5 e You can see a picture of these icons again on page 21 What s a Microcontroller ASCIIName bs2 Use ASCII code in a DEBUG command to display the words BASIC Stamp 2 SSTAMP BS2 SPBASIC 2 5 DHE 66 665 895 79 617 324 8S Ls 97 Los Lila 32 50 END Chapter 1 Getting Started Page 31 How ASCIIName bs2 Works Each letter in the DEBUG command corresponds to one ASCII code symbol that appeared in the Debug Terminal DEBUG 66 65 83 73 67 32 83 116 97 109 112 32
241. ment Display 165 Bi Color LED 61 LED 40 Photoresistor 190 Piezoelectric Speaker 219 Potentiometer 140 Pushbutton Normally Open 71 Resistor 38 Transistor NPN 265 PAUSE 49 PBASIC Commands DEBUG 25 DEBUGIN 120 23 292 DEC 120 DO LOOP 49 END 25 EXIT 292 FOR NEXT 53 56 114 FREQOUT 221 GOSUB 206 HIGH 49 IF ELSEIF ELSE 85 IF THEN ELSE 81 LOOKDOWN 182 LOOKUP 179 81 LOW 49 ON GOSUB 287 PAUSE 49 PULSOUT 113 RANDOM 95 RCTIME 151 52 152 READ 202 3 230 RETURN 206 SELECT CASE 246 50 TOGGLE 272 UNTIL 93 WRITE 199 201 230 PBASIC Directives DATA 230 33 PBASIC 24 PIN 287 Stamp 24 PBASIC I O Registers DIRH 175 78 IN3 77 OUTH 175 78 PBASIC Operators 177 94 244 95 244 Index Page 333 DCD 243 Order of Execution 242 Parenthesis 242 Photoresistor 189 90 RC Time Circuit 190 Piano Keyboard 227 Piezoelectric Element 220 Speaker 219 Pin Map 166 268 Pitch 219 Polling 90 Potentiometer 139 41 Digital 267 77 Terminals 140 Prototyping Area Input Output Pins 41 Power Terminals 41 Prototyping Areas Socket 41 Pseudo Random 96 Pull Up Resistor 79 Pulse 113 PULSOUT 113 Pushbutton 71 72 Circuit 75 77 Normally Open 72 R Radio Control 153 RANDOM 95 Page 334 What s a Microcontroller RCTIME 151 52 152 READ 199 230 Receive Windowpane 120 121 Reference 323 Reference N
242. mon anode would mean that all the anodes are connected together Q3 A parallel bus Q4 LOOKUP and LOOKDOWN handle list of values Chapter 6 Digital Display Page 187 E1 The first step for configuring ouTH is set to 1 in each bit position specified as HIGH So bits 8 10 and 12 get set to 1 Then put a 0 for each Low so bits 9 11 and 13 get a 0 as shown To configure DIRH the specified pins 8 10 12 9 11 and 13 must be set as outputs by setting those bit to 1 15 and 14 are configured as inputs by placing zeroes in bits 15 and 14 The second step is to translate this to a PBASIC statement Bit 15 1413121110 9 8 Bit 15 14 13 12 11 10 9 8 OUTH 0 0 O 1 0 1 0 1 DIRH 0 0 1 21 1 3 1 I OUTH 00010101 DIRH 00111111 E2 The key to solving this problem is to draw out each letter and note which segments must be lit Place a 1 in every segment that is to be lit Translate that to the binary OUTH value Letter LED Segments BA FG CDE OUTL Value Cone a e f a b c g 11110101 11110101 uae C a f e d 01100011 01100011 d b c d e g 10010111 10010111 F a f e g 01110001 01110001 H f e b c g 10110101 10110101 I fre 00100001 00100001 n e g C 00010101 00010101 P all but d and e 11110001 11110001 S a f g c d 01110110 01110110 12345 From Figure 6 2 p 160 Common P1 Use the Schematic from Figure 6 10 on page 172 To solve this pro
243. mplified current in equals current out The current that enters an LED circuit from Vdd is the same amount of current that leaves it through Vss Also if you connect three LEDs to the BASIC Stamp and each LED circuit draws 5 mA it means the BASIC Stamp has to supply all the circuits with a total of 15 mA Example Calculation One Circuit Two Circuits Calculating how much current an LED circuit draws takes two steps 1 Figure out the voltage across the resistor 2 Use Ohm s Law to figure out the current through the resistor Figure F 2 shows how to figure out the voltage across the resistor The voltage supplied is on the left it s 5 V The voltages used are on the right The voltage we don t know at the start is Vp the voltage across the resistor But we do know that the voltage across the LED is 1 6 V the diode forward voltage We also know that the voltage across the parts has to add up to 5 V because of Kirchoff s Voltage Law The difference between 5 V and 1 6 V is 3 4 V so that must be the voltage across the resistor Vr Page 324 What s a Microcontroller 4 Vdd VR V i R V 1 6y 5y Figure F 2 5V Voltage Across Vp 5V 1 6V the Circuit t Resistor and z iy Vg 3 4V LED Vss Kilo is metric for 1000 The metric way of saying 1000 is kilo and it s abbreviated with the lower case k Instead of writing 1000 Q you can write 1 kQ Either way it s pronounced one kilo ohm Likewise 20
244. n and another button to get the servo to rotate in the other direction When no buttons are pressed the servo will hold whatever position it moved to Extra Parts for Pushbutton Servo Control The same parts from the previous activities in this chapter are still used You will need to gather the following parts for the pushbutton circuits 2 Pushbuttons normally open 2 Resistors 10 kQ brown black orange 2 Resistors 220 Q red red brown 3 Jumper wires Chapter 4 Controlling Motion Page 129 Adding the Pushbutton Control Circuit Figure 4 20 shows the pushbutton circuits that you will use to control the servo Vdd Vdd Figure 4 20 Pushbutton Circuits for Servo Control y Add this circuit to the servo LED circuit that you have been using up to this point When you are done your circuit should resemble Figure 4 21 if you are using the Board of Education Rev C Figure 4 22 if you are using the HomeWork Board Figure 4 23 if you are using the Board of Education Rev B Page 130 What s a Microcontroller P15 P14 P13 P12 P11 P10 o000000 icy e gai Vdd Vin Pt l C P14 mir Cp uo _ 11 P13 P12 P11 P10 O
245. n it has circles on its underside that show where each rubber foot should be attached For the HomeWork Board just place a rubber foot next to each plated hole at each corner Figure 1 25 Rubber Foot Affixed to Underside of Board of Education left and HomeWork Board right Next the Board of Education or BASIC Stamp HomeWork Board should be connected to your PC or laptop by a serial cable V Connect your serial cable to an available COM port on the back of your computer as shown in Figure 1 26 Page 16 What s a Microcontroller USB Port Adapter If you are using a USB to Serial Adapter Connect the USB end to your PC s USB port w V Connect the COM port adapter either directly to your Board of Education or HomeWork Board or connect it to the serial cable as shown in Figure 1 26 Figure 1 26 PC or Laptop COM Port Figure 1 27 3 position Switch Plug the serial cable into an available COM port Set to the 0 position to turn off the on your PC or laptop power If you are using the BASIC Stamp 2 module and Board of Education y Set the 3 position switch on the Board of Education to position 0 as shown in Figure 1 27 4 _ Only the Board of Education Rev C has a 3 position switch To turn off power on a Board J of Education Rev B simply disconnect the power source by either unplugging the DC supply wor the battery These are shown in Figure 1 28 step 3 or 4 y If your BAS
246. n the player has to let go of the pushbutton as fast as he or she can The time between when the LED turns green and when the pushbutton is tracked by the program is used as a measure of reaction time The example program also demonstrates how polling and counting work Polling is the process of checking something over and over again very quickly to see if it has changed Counting is the process of adding a number to a variable each time something does or does not happen In this program the BASIC Stamp will poll from the time the bi color LED turns green until the pushbutton is released It will wait 1 1000 of a second by using the command Pause 1 Each time it polls and the pushbutton is not yet released it will add 1 to the counting variable named timeCounter When the pushbutton is released the program stops polling and sends a message to the Debug Terminal that displays the value of the timeCounter variable Example Program ReactionTimer bs2 y Enter and run ReactionTimer bs2 y Follow the prompts on the Debug Terminal see Figure 3 15 What s a Microcontroller ReactionTimer bs2 ti DE DO Chapter 3 Digital Input Pushbuttons Page 91 4 Debug Terminal 1 l Es Com Port Baud Rate Parity COM E sso 0 z None pa Bits Flow Control 1 M DIRT ats 3 jl RK DSR CTS Press and hold pushbutton to make light turn red When light turns green let go as fast as you can Your time was 7
247. n an index the LOOKDOWN command gives you an index based on a number Example Program SimpleLookdown bs2 Figure 6 14 Schematic of Potentiometer Circuit Added to the Project Figure 6 15 Project Wiring Diagram This example program demonstrates how the LooKDowN command works V Enter and run SimpleLookdown bs2 V Run the program as is with the value variable set equal to 167 and use the Debug Terminal to observe the value of index V Try setting the value variable equal to each of the other numbers listed by the LOOKDOWN command 7 85 19 28 Chapter 6 Digital Display Page 183 V Re run the program after each change to the value variable and note which value from the list gets placed in the index variable Unless you tell it to make a different kind of comparison the LookDown command checks to see if a value is equal to an entry in the list You can also check to see if a value is greater than less than or equal to etc For example to search for an entry that is less than or equal to the value variable use the lt operator just before the first bracket that starts the list y Modify SimpleLookdown bs2 by substituting this value and LOOKDOWN statement value 35 LOOKDOWN value lt 7 19 28 85 167 index y Experiment with different values and see if the index variable displays what you would expect A Trick question What happens if your value is greater than 167 This little twist i
248. n the LOOKDOWN command can cause problems because the LOOKDOWN command doesn t make any changes to the index What s a Microcontroller SimpleLookdown bs2 Debug an index using a value and a lookup table SSTAMP BS2 SPBASIC 2 5 value VAR Byte index VAR Nib value 167 DEBUG value LOOKDOWN value 7 85 19 167 28 index DEBUG index CR DEBUG Change the value variable to a CR Holiinesizevale sakblideysac ale louis dais g Cle ity wey AO AS wig Bom Kite CR Run the modified program and CR check to see what number the CR Page 184 What s a Microcontroller LOOKDOWN command places in the CR index variable END Example Program DialDisplay bs2 This example program mirrors the position of the potentiometer s knob by lighting segments around the outside of the 7 segment LED display as shown in Figure 6 16 Figure 6 16 Displaying the Potentiometer s Position with the 7 Segment LED Display y Enter and run DialDisplay bs2 V Twist the potentiometer s input shaft and make sure it works V When you run the example program it may not be as precise as shown in Figure 6 16 Adjust the values in the lookdown table so that that the digital display more accurately depicts the position of the potentiometer What s a Microcontroller DialDisplay bs2 Display POT position using 7 segment LED display SSTAMP BS2 SPBASIC 2 5 DEBUG
249. n used to measure the Chapter 7 Measuring Light Page 191 decay time is different P2 Second the variable resistor is now a photoresistor instead of a potentiometer Build the circuit shown in Figure 7 2 and Figure 7 3 P2 220 Q X3 Ky Vss P15 P14 P13 P12 P11 P10 P8 P7 P6 P5 P4 P3 P2 P1 PO X2 0 01 pF Programming the Photoresistor Test The first example program TestPhotoresistor bs2 is really just a slightly revised version of ReadPotWithRcTime bs2 from Chapter 5 Activity 3 The potentiometer circuit from Chapter 5 was connected to I O pin P7 The circuit in this activity is connected to P2 Because of this difference the example program has to have two commands updated to make it work The command that was HIGH 7 since the potentiometer circuit was connected to P7 is now HIGH 2 since the photoresistor circuit is connected to P2 For the same reason the command that was RCTIME 7 time 1 Figure 7 2 Photoresistor RC time Circuit Schematic Figure 7 3 Photoresistor RC time Wiring Diagram time is NOW RCTIME 2 1 Page 192 What s a Microcontroller Example Program TestPhotoresistor bs2 Instead of twisting the potentiometer s knob the circuit is tested by exposing the light
250. nds look a certain way in the Debug Terminal DEC is an example of a formatter that makes the Debug Terminal display a decimal value An example of a control character is cr which is used to send a carriage return to the Debug Terminal The text or numbers that come after a cr will appear on the line below characters that came before it You can modify your program so that it contains more DEBUG commands along with some formatters and control characters Here s an example of how to do it First save the program under a new name by clicking File and selecting Save As A good new name for the file would be FirstProgramY ourTurn bs2 y Modify the comments at the beginning of the program so that they read What s a Microcontroller FirstProgramYourTurn bs2 BASIC Stamp sends messages to Debug Terminal y Add these three lines between the first DEBUG command and the END command DEBUG CR What s 7 X 11 DEBUG CR The answer is DEBUG DEC 7 11 Page 26 What s a Microcontroller y Save the changes you made by clicking File and selecting Save Your program should now look like the one shown in Figure 1 42 V Run your modified program You will have to either select Run from the Run menu again like in Figure 1 39 or click the Run button like in Figure 1 41 7 BASIC Stamp C Program Files Parallax Inc Stamp Editor v2 0 Beta 1 B52 FirstProgramYourTurn bs2 i 0 x File Edit Directive Run Help Ose e S PAA SS PHP 4 A
251. ng the circuit shown in the schematic use the wiring diagram in Figure 3 13 as a guide y Modify ReadPushbuttonState bs2 so that it reads IN4 instead of IN3 and use it to test your second pushbutton circuit Page 84 What s a Microcontroller Figure 3 12 Schematic Two Pushbuttons and LEDs Connecting wires with dots There are three places where wires intersect in Figure 3 12 but only two dots Wires only connect if there is a dot at the intersection The wire that Lb connects the P4 pushbutton to the 10 kQ resistor does not connect to the P3 pushbutton circuit because there is no dot Chapter 3 Digital Input Pushbuttons Page 85 Vdd vin Lbs Figure 3 13 Wiring Diagram Two Pushbuttons and LEDs Programming Pushbutton Control In the previous activity you experimented with making decisions using an IF THEN ELSE statement There is also such a thing as an IF ELSEIF ELSE statement It works great for deciding which LED to flash on and off The next example program shows how it works Example Program PushbuttonControlOffwoLeds bs2 V Enter PushbuttonControlOffwoLeds bs2 into the BASIC Stamp Editor and run it Verify that the LED in the circuit connected to P14 flashes on and off while the pushbutton in the cir
252. not to flash the LED Example Program PushbuttonControlledLed bs2 V Enter PushbuttonControlledLed bs2 into the BASIC Stamp Editor and run it y Verify that the LED flashes on and off while the pushbutton is pressed and held down y Verify that the LED does not flash when the pushbutton is not pressed down What s a Microcontroller PushbuttonControlledLed bs2 Check pushbutton state 10 times per second and blink LED when pressed SSTAMP BS2 0 PBASIC 2 5 DO Page 82 What s a Microcontroller DEBUG IN3 IF IN3 1 THEN HIGH 14 PAUSE 50 LOW 14 PAUSE 50 ELSE PAUSE 100 ENDIF LOOP How PushbuttonControlledLed bs2 Works This program is a modified version of ReadPushbuttonState bs2 from the previous activity The Do LooP and DEBUG IN3 commands are the same The PAUSE 250 was replaced with an IF THEN ELSE statement When the condition after the IF is true IN3 1 the commands that come after the THEN statement are executed They will be executed until the ELSE statement is reached at which point the program skips to the ENDIF and moves on When the condition after the IF is not true IN3 0 the commands after the ELSE statement are executed until the ENDIF is reached You can make a detailed list of what a program should do to either help you plan the program or to describe what it does This kind of list is called pseudo code and the example below uses pseudo code to describe how PushbuttonCon
253. ns is pressed the value of duration increases If the other pushbutton is pressed the value of duration decreases A nested IF THEN statement is used to decide if the duration variable is too large greater than 1000 or too small smaller than 500 Page 132 What s a Microcontroller Example Program ServoControlWithPushbuttons bs2 This example program makes the servo s horn rotate counterclockwise when the pushbutton connected to P4 is pressed The servo s horn will keep rotating so long as the pushbutton is held down and the value of duration is smaller than 1000 When the pushbutton connected to P3 is pressed the servo horn rotates clockwise The servo also is limited in its clockwise motion because the duration variable is not allowed to go below 500 The Debug Terminal displays the value of duration while the program is running V Enter the ServoControlWithPushbuttons bs2 program into the BASIC Stamp Editor and run it Verify that the servo turns counterclockwise when you press and hold the pushbutton connected to P4 y Verify that as soon as the limit of duration gt 1000 is reached or exceeded that the servo stops turning any further in the counterclockwise direction y Verify that the servo turns clockwise when you press and hold the pushbutton connected to P3 y Verify that as soon as the limit of duration lt 500 is reached or exceeded that the servo stops turning any further in the clockwise direction What s
254. nseeeeeseesaseaeenseeeeeeeees 315 Appendix F More about Electricity ccccsseececeeeeeeeeeeneeeeeeeneeeeeeeeneeseeesneeseeeenes 319 Appendix G RTTTL Format Summary ccceseceeeeeeseeeeesneeenseeeeeseeessnaeenseeeeeeeees 327 Preface Page v Preface This text answers the question What s a microcontroller by showing students how they can design their own customized intelligent inventions with Parallax Inc s BASIC Stamp microcontroller module The activities in this text incorporate a variety of fun and interesting experiments designed to appeal to a student s imagination by using motion light sound and tactile feedback to introduce new concepts These activities introduce students to a variety of basic principles in the fields of computer programming electricity and electronics mathematics and physics Many of the activities facilitate hands on presentation of design practices used by engineers and technicians in the creation of modern machines and appliances using common inexpensive parts AUDIENCE This text is organized so that it can be used by the widest possible variety of students as well as independent learners Middle school students can try the examples in this text in a guided tour fashion by simply following the check marked instructions and instructor supervision At the other end of the spectrum pre engineering students comprehension and problem solving skills can be tested with the qu
255. nt Workbook Version 1 1 Parallax Inc 2002 Every Stamps in Class robotics text uses RCTIME to measure resistive sensors to detect a variety of conditions Each condition leads to math and decisions and the end result is robot movement Basic Analog and Digital Student Guide Version 2 0 Parallax Inc 2003 Basic Analog and Digital uses the potentiometer to create a variable voltage called a voltage divider which is analyzed by an analog to digital converter A potentiometer is also used as an input device to set the frequency of a 555 timer This text takes a closer look at the math involved in RC voltage decay Applied Sensors Student Guide Version 1 3 Parallax Inc 2003 RCTIME is used extensively in this book to collect data from a variety of sensors Industrial Control Student Guide Version 2 0 Parallax Inc 2002 This book introduces techniques used extensively in industry for controlling machines based on sensor input The techniques fall under the general category of control systems Chapter 6 Digital Display Page 165 Chapter 6 Digital Display THE EVERY DAY DIGITAL DISPLAY Figure 6 1 shows a display on the front of an oven door When the oven is not in use it displays the time When the oven is in use it displays the oven s timer cooking settings and it flashes on and off at the same time an alarm sounds to let you know the food is done A microcontroller inside the oven door monitors the pu
256. ntains a table with six bit patterns that are used to create the circular pattern around the outside of the 7 segment LED display By adding 1 to the index variable each time the subroutine is called it causes the next bit pattern in the sequence to get placed in outH There are only entries in the LOOKUP command s lookup table for index values from 0 through 5 What happens when the value of index gets to 6 The lookup command doesn t automatically know to go back to the first entry but you can use an IF THEN statement to fix that problem The command IF index 6 THEN index 0 resets the value of index to 0 each time it gets to 6 It also causes the sequence of bit patterns placed in OUTE to repeat itself over and over again This in turn causes the 7 segment LED display to repeat its circular pattern over and over again Update Display IF index 6 THEN index 0 BAFG CDE LOOKUP index 01000000 10000000 00000100 00000010 00000001 00100000 OUTH index index 1 RETURN Your Turn Adjusting the Meter s Hardware and Software There are two ways to change the sensitivity of the meter First the software can be changed For example the 7 segment LED display will cycle at one tenth the speed if you multiply the time variable by 10 in the Delay subroutine and it will cycle twice as fast if you divide the time variable by 2 y Modify LightMeter bs2 so that the time variable is multiplied by 10 The easiest way t
257. o do this is to change Page 214 What s a Microcontroller PAUSE time PAUSE time 10 in the Delay subroutine Run the modified program and test to make sure the cycling of the 7 segment LED display is now one tenth of what it was before You can also try multiplying the time variable by other values such as 5 or 20 or dividing by 2 using PAUSE time 2 You can also make the display cycle at one tenth the speed by swapping the 0 01uF capacitor for the 0 1 uF capacitor Remember that when you use a capacitor that is ten times as large the RC time measurement will become ten times as long Replace the 0 01 uF capacitor with a 0 1 uF capacitor Run the program and see if the predicted effect occurred Which is better adjusting the software or the hardware You should always try to use the best of both worlds Pick a capacitor that gives you the most accurate measurements over the widest range of light levels Once your hardware is the best it can be use the software to automatically adjust the light meter so that it works well for the user both indoors and outdoors This takes a considerable amount of testing and refinement but that s all part of the product design process Chapter 7 Measuring Light Page 215 SUMMARY This chapter introduced a second way to use the RCTIME command by using it to measure light levels with a photoresistor Like the potentiometer the photoresistor is a variable resistor
258. o the breadboard When the potentiometer s legs are straight they maintain better contact with the breadboard sockets Page 142 What s a Microcontroller Vdd Vdd Vin Vss X3 220 9 P44 Pot p10 10 kQ ps Oo f nc P4 Figure 5 5 Potentiometer LED Test Circuit EJ X2 Testing the Potentiometer Circuit y Turn the potentiometer clockwise until it reaches its mechanical limit shown in Figure 5 6 Handle with care If your potentiometer will not turn this far do not try to force it Just turn wy it until it reaches its mechanical limit otherwise it might break Gradually rotate the potentiometer counterclockwise to the positions shown in Figure 5 6 b c d e and f noting the how brightly the LED glows at each position How the Potentiometer Circuit Works Figure 5 6 7 Potenti ter t Shaft e otentiometer Input Sha f a through f show the potentiometer s wiper terminal set to different positions The total resistance in your test circuit is 220 Q plus the resistance between the A and W terminals of the potentiometer This value could be anywhere from 0 to 10 kQ As you Chapter 5 Measuring Rotation Page 143 turn the potentiometer s input shaft th
259. oard of Education Rev B Carrier Board for BASIC Stamp modules Appendix D Batteries and Power Supplies Page 311 Appendix D Batteries and Power Supplies 9 V BATTERIES For best results 9 V batteries are recommended 9 V battery specifications Look for batteries with ratings similar these Not Rechargeable Rechargeable e Alkaline Ni Cad Nickel Cadmium a e Ni MH Nickel Metal Hydride fe Pauly For best results the battery s milliamp hour mAh rating should be w 100 or higher Not all chargers work for both types of batteries Make sure that your charger is recommended for the battery you are using either Ni Cad or Ni MH Follow all battery and charger instructions and caution statements PARALLAX DC SUPPLIES Parallax carries several power supplies that can be used with the Board of Education Rev C only For the servo experiments in this text the jumper between the X4 and X5 servo headers should be set to Vdd The supplies listed in Table D 1 are designed for AC outlets in the USA and both have 2 1 mm center positive barrel plugs that connect to the Board of Education s barrel jack Table D 1 Power Supplies You Can Get from Parallax Inc Input Output Parallax Part VAC Hz VDC mA 750 00008 120 60 9 300 750 00009 120 60 7 5 1000 Page 312 What s a Microcontroller GENERIC DC SUPPLIES For best results with the BASIC Stamp HomeWork Board or
260. ocontroller a2 eee N Identification Figure E 1 Port Status Identification Window Example BASIC Stamp 2 not found on COM ports Close the Identification Window Make sure the serial cable is properly connected Try the Run Identify test again If you know the number of the COM port but it does not appear in the Identification Window use the Edit Port List button to add that COM port and then try the Run Identify test again If you have more than one COM port try connecting your Board of Education or BASIC Stamp HomeWork Board to a different COM port and see if Run Identify works then If you have a second computer try it on the different computer If you get the error message No BASIC Stamp Found but the Run Identify test shows a Yes in both columns for one of the COM ports you may need to change a setting to your FIFO Buffers This is happens occasionally with Microsoft Windows 98 and XP users Make a note of the COM port with the Yes messages and try this Windows 98 L Ll ee 2A Click on your computer desktop s Start button Select Settings Control Panel System Device Manager Ports COM amp LPT Select the COM port that was noted by the Run Identify test Select Properties Port Settings Advanced Uncheck the box labeled Use FIFO Buffers then click OK Click OK as needed to close each window and return to the BASIC Stamp Editor
261. of values or mixed to create a variety of effects Making musical notes also depends on frequency duration and pauses The value of the FREQOUT command s Duration argument is determined by the tempo of the song and the duration of the note whole half quarter etc The Freq1 value of the note is determined by the note s letter and octave Rests between notes are used to set the duration of the PAUSE command Playing simple songs using the BASIC Stamp can be done with a sequence of FREQOUT commands but there are better ways to store and retrieve musical data DATA directives along with their optional Symbo1 labels were used to store byte values using no prefix and word values using the Word prefix The READ command was used to retrieve values stored by DATA directives The READ command s Address argument always used the DATA directive s optional Symbol label to differentiate between different types of data Some the symbol labels that were used were Notes Durations Dots and Octaves Musical data can be stored in formats that lend themselves to translation from sheet music The sheet music style data can then be converted into Frequency using the LOOKUP and LOOKDOWN commands Mathematic operations can also be performed on variable values to change the octave of a note by dividing its frequency by a power of two Mathematic operations are also useful for note durations given either the tempo or the duration of a whole note SELECT
262. ogram is running e BASIC Stamp Hor eWork Board Heeder for conneothig BASIC Stamp I O pins Reset button may be to circuits on the pressed and released breadboard to restart your BASIC 220 Q resistors to Stamp program protect each lO pin Figure C 3 Parallax Inc s BASIC Stamp HomeWork Board project platform features a surface mounted BASIC Stamp 2 microcontroller module Page 310 What s a Microcontroller The Board of Education Rev B Figure C 4 shows Parallax Inc s Board of Education Rev B carrier board Its major components and their functions are indicated by labels a Voltage regulator supplies Board of Education Application Module AppMod with regulated VDC Vdd and ground Vss connector for add on modules 4 RIC servo connection Power jack 2 1 mm center positive 6 9 VDC J ports for robotic projects 9 V battery dip iy Header for connecting Filter capacitors for power Vdd Vin Vss to 5 VDC regulators on circuits on the breadboard Board of Education and BASIC Stamp Breadboard rows are Sera Onan prs connected horizontally ng separated by the trough programs and debug terminal runtime os eui Erm FS S es communication e nee ducution ane Header for connecting BASIC Stamp lO pins Socket for any 24 pin to circuits on the breadboard BASIC Stamp module Power indicator light Reset button may be pressed and released to restart your BASIC Stamp program Figure C 4 Parallax Inc s B
263. ogrammable read only memory That s quite a mouthful and pronouncing each of the first letters in EEPROM isn t much better When people talk about an EEPROM it is usually pronounced E E Prom Page 198 What s a Microcontroller 2 K EEPROM retains your PBASIC source code Figure 7 7 EEPROM Chip on BASIC Stamp dvaes SS SH kwijt 4 EEN Figure 7 8 shows a window called Memory Map You can view this window by clicking Run and selecting Memory Map The Memory Map uses different colors to show how both the BASIC Stamp module s RAM variables and EEPROM program memory are being used The EEPROM Map has two graphs The bar at the far left shows that only a small fraction of the program memory is used to store the photoresistor program from Activity 2 By scrolling to the bottom of the FEPROM Map s main window and counting the bytes highlighted in blue you will find that only 101 bytes out of the 2048 byte EEPROM are used for the program The remaining 1947 bytes are free to store data y Memory Map EEPROM 4 Full Untitled1 x RAM Map BHBIZNWIB7E54 3210 agg CECE Figure 7 8 COCO eeccoeee Regs CEET Memory Map REGS 00 00 00 00 00 00 00 00 00 00 00 pE To view this window ano click Run and select Rec2 IIIT Memory Map Legend EPs Be E Bit E Wod EE Nibble CI Unused PROM Legend Dis ASCI E Undef Data H Progra
264. onnected Always disconnect the power from your Board of Education or HomeWork w Board before you walk away even if you only plan on leaving it alone for a minute or two Page 32 What s a Microcontroller Disconnecting Power With the Board of Education Rev C disconnecting power is easy If you are using the Board of Education Rev C power is disconnected by moving the 3 position switch to position 0 by pushing it to the left as shown in Figure 1 49 Sout wv pA rop 14Y9 uuu sn PW ge Css BiA Pis P9 o0000 00000 ATND ORst yaa Vin P8 goood ooo000 vss D vad P7 ooo0o00 o0000 Po D Opis P6 ooo0o00 o0000 z pip p14 pQ P5 Ooooo 00000 Figure 1 49 2 Bom Mes Wl pgss pagan pa B Gee a H oo000 jooooo Turning the Power off Ps H p10 Pt ooooolL_jooooo Pe p gP9 m Po o0000 ooooo P7 Ups EE 00000 o0000 01 2 Board of Educatio Board of Education www stampsinclass com ozo ana Rev C gt Do not remove the BASIC Stamp module from its socket in the Board of Education Every time the BASIC Stamp is removed and re inserted into the socket on the Board of w Education you risk damaging it You do not need to remove it for storage ee Disconnecting the BASIC Stamp HomeWork Board s power is easy too If you are using the BASIC Stamp HomeWork Board disconnect the battery as shown in Figure 1 50 9 V Transistor BaYery 9 V Transist
265. ons and educator feedback while traveling the nation teaching Parallax Educators Courses Andy studied Electrical and Electronic Engineering at California State University Sacramento and this is his third Stamps in Class Student Guide He is also a contributing author of several papers that address the topic of microcontrollers in pre engineering curricula When he s not writing educational material Andy does product engineering for Parallax Parallax wishes to thank StampsInClass Yahoo Group member Robert Ang for his thorough draft review and detailed input and veteran engineer and esteemed customer Sid Weaver for his insightful review Thanks also to Stamps in Class authors Tracy Allen Applied Sensors and Martin Hebel Industrial Control for their review and recommendations Andy Lindsay wishes to thank his father Marshall and brother in law Kubilay for their expert musical advice and suggestions Stamps in Class was founded by Ken Gracey and Ken wishes to thank the Parallax staff for the great job they do Each and every Parallaxian has made contributions to this and every Stamps in Class text Chapter 1 Getting Started Page 1 Chapter 1 Getting Started HOW MANY MICROCONTROLLERS DID YOU USE TODAY A microcontroller is a kind of miniature computer that you can find in all kinds of gizmos Some examples of common every day products that have microcontrollers built in are shown in Figure 1 1 If it has buttons and a digital displa
266. or Battery Figure 1 50 Disconnecting the power to the HomeWork Board Reset amp HomeWork Board Aayeg uey 1 9948M0d If you are using a Board of Education Rev B you will not have a 3 position switch Either unplug power supply or remove the 9 V battery whichever you are using Your Turn V Disconnect the power to your board now Chapter 1 Getting Started Page 33 SUMMARY This chapter guided you through the following An introduction to some devices that contain microcontrollers An introduction to the BASIC Stamp module A tour of some interesting inventions made with BASIC Stamp modules Where to get the free BASIC Stamp Editor software you will use in just about all of the experiments in this text How to install the BASIC Stamp Editor software An introduction to the BASIC Stamp module Board of Education and HomeWork Board How to set up your BASIC Stamp hardware How to test your software and hardware How to write and run a PBASIC program Using the DEBUG and END commands Using the cr control character and DEC formatter How to use the BASIC Stamp Editor s Help and the BASIC Stamp Manual A brief introduction to ASCII code How to disconnect the power to your Board of Education or HomeWork Board when you re done Questions l 3 1 What is a microcontroller Is the BASIC Stamp module a microcontrol
267. ortant to test components individually before building them into a larger system This activity focuses on building and testing two different LED circuits The first circuit is the one that makes the LED emit light The second circuit is the one that makes it not emit light In the activity that comes after this one you will build the LED circuit into a larger system by connecting it to the BASIC Stamp You will then write programs that make the BASIC Stamp cause the LED to emit light then not emit light By first testing each LED circuit to make sure it works you can be more confident that it will work when you connect it to a BASIC Stamp Introducing the Resistor A resistor is a component that resists the flow of electricity This flow of electricity is called current Each resistor has a value that tells how strongly it resists current flow This resistance value is called the ohm and the sign for the ohm is the Greek letter omega Q The resistor you will be working with in this activity is the 470 resistor shown in Figure 2 2 The resistor has two wires called leads and pronounced leeds one coming out of each end There is a ceramic case between the two leads and it s the part that resists current flow Most circuit diagrams that show resistors use the jagged line symbol on the left to tell the person building the circuit that he or she must use a 470 Q resistor This is called a schematic symbol The drawing on the right
268. otch 268 Resistance 319 Resistor 38 40 48 Color Codes 39 40 Leads 38 Pull Down 79 Pull Up 79 Tolerance 39 Rest 233 RETURN 206 Ringtone 245 Robot 2 4 RTTTL Format 245 251 57 327 28 AS Scaling 155 Schematic Dots Indicate Connections 84 Drawing 45 Schematic Symbol 7 Segment Display 166 Bi Color LED 61 LED 40 Photoresistor 190 Piezoelectric Speaker 219 Potentiometer 140 Pushbutton Normally Open 71 Resistor 38 Transistor NPN 265 Seed 96 SELECT CASE 246 Sensor 189 Sensor Array 281 287 Servo 103 4 Cable 103 Case 103 Caution Statement 104 154 Connecting to BASIC Stamp 105 13 Header 106 Horn 103 Jack 103 Potentiometer Controlled 153 Power Supply Caution 314 Sharp 228 Speaker piezoelectric 220 Stamp Plot Lite 193 97 Status indicator 37 STR 292 Subroutine 206 13 Label 206 Subsystem Integration 281 Superposition 226 Syntax highlighting 24 T Tempo 233 Terminal Piezoelectric Speaker 220 TOGGLE 272 Token 263 Tolerance 39 Transistor 264 265 67 2N3904 265 Base 265 Base Current 266 Collector 265 Emitter 265 NPN 265 Switching 266 Transmit Windowpane 120 121 U UNTIL 93 US232B 301 USB to Serial Adapter 6 16 301 V Variables 53 55 247 Index Page 335 Array 292 Bit 55 247 Byte 55 247 Nib 55 247 Word 55 247 Vdd 41 46 323 Vin 41 323 Volt 319 Voltage
269. our sensor circuits This example will demonstrate how to program the BASIC Stamp to display a terminal with a menu that a technician might use to monitor the sensors Programming a Menu System and Using the Input Output PIN Directive The on cosus command can be very useful for menus ON offset GOSUB Target1 Target2 Target3 In the next example program the on GosuB command uses the value of a variable named request to direct it to one of four subroutines If the value of request is 0 the program executes a GOSUB Read Pushbutton 1 If the Value of request is 1 the program executes a GOSUB Read Pushbutton _2 and so on ON request GOSUB Read_Pushbutton_1 Read _Pushbutton_2 Read _ Pot Read_Photoresistor You can use the PIN directive to give a name to each I O pin you are going to use in a PBASIC program The BASIC Stamp Editor will then figure out whether you are using the I O pin as an input or an output or both The PIN directive s syntax is PinName PIN PinNumber Page 288 What s a Microcontroller The next example program demonstrates how you can declare and then use a PinName For example the BASIC Stamp Editor assumes that you want to display the input value of an I O pin 1N3 if you are using the Pb1Pin PinName in a DEBUG command This DEBUG command will display a 1 or 0 depending on whether the pushbutton connected to P3 is pressed or not pressed Why Because the BASIC Stamp Editor knows to substitute IN3
270. own because it more clearly shows how the values in oUTH line up with the I O pins The command ouTH 11010110 uses binary zeros to set I O pins P8 P11 and P13 low and it uses binary ones to set P9 P10 P12 P14 and P15 high The line just before the command is a comment that shows the segment labels line up with the binary value that turns that segment on off The next example program shows how to set ouTH to binary numbers to make the 7 segment LED display count from zero to nine i w Inside the HIGH and LOW commands The command HIGH 15 is really the same as OUT15 1 followed by DIR15 1 Likewise the command LOW 15 is the same as OUT15 1 followed by DIR15 1 If you want to change P15 back to an input use DIR15 0 You can then use IN15 to detect instead of send high low signals Your Turn Displaying A through F N N Figure out what bit patterns combinations of zeros and ones you will need to display the letters A b C d E and F Modify SevenSegment0to9 so that it displays A b C d E F Chapter 6 Digital Display Page 179 Decimal vs Hexadecimal The basic digits in the decimal base 10 number system are 0 _ 1 2 3 4 5 6 7 8 and 9 In the hexadecimal base 16 number system the basic digits iy are 0 1 2 3 4 5 6 7 8 9 A b C d E F Base 16 is used extensively in both computer ew and microcontroller programming Once you figure out how to display the char
271. ows an excerpt from the BASIC Stamp Manual v2 0 Contents section showing that information on the DEBUG command is found on page 97 Figure 1 47 Finding the DEBUG Command in the Table of Contents Figure 1 48 shows an excerpt from page 97 in the BASIC Stamp Manual v2 0 The DEBUG command is explained in detail here along with example programs to demonstrate how the DEBUG command can be used V Look over the BASIC Stamp Manual s explanation of the DEBUG command y Count the number of example programs in the DEBUG section How many are there 5 BASIC Stamp Command Reference DEBUG DEBUG Bs1 Bsz asze Bs2sx Bszp DEBUG OutputData OutputData Function Display information on the PC screen within the BASIC Stamp editor program This command can be used to display text or numbers in various formats on the PC screen in order to follow program flow called debugging or as part of the functionality of the BASIC Stamp application Figure 1 48 Reviewing the DEBUG Command in the BASIC Stamp Manual Page 30 What s a Microcontroller Your Turn Use the BASIC Stamp Manual s Index to look up the DEBUG command V Look up the END command in the BASIC Stamp Manual ACTIVITY 6 INTRODUCING ASCII CODE In Activity 4 you used the DEC formatter with the DEBUG command to display a decimal number in the Debug Terminal But what happens if you don t use the DEc formatter with a number If you use the DEBUG com
272. oximately 250 members ERRATA While great effort is made to assure the accuracy of our texts errors may still exist If you find an error please let us know by sending an email to editor parallax com We continually strive to improve all of our educational materials and documentation and frequently revise our texts Occasionally an errata sheet with a list of known errors and corrections for a given text will be posted to our web site www parallax com Please check the individual product page s free downloads for an errata file Table of Contents Page i Table of Contents PROTACC wescecectcc tice r a teed vise e a ease enable ar aO Aaaa n ean KEENE v AUCIONCO deie ni i ai Seu and Pet eaten E a i E a a a e a E iEn v Support and Discussion Group 2 cccceeeeeceeeeeeceeeeeeeeeeeeeeeeeeeeeeeeeeseceeeeeeseeeesessneeeetees v Teachers ETEO E AE A E E E E eto vi The Stamps in Class Curriculum ccceeeecceeeeeeeeeeeeeeeeeececeeeeecaceseeeeeeeseseeeeeeneeees vi Foreign Translations siingi derie aaie e drien i e anana apia E aa viii Special Oop DU O S sc ee eae ee ie Lee de es oe aah ae viii Chapter 1 Getting Started cccssccssseeesseeeeesecesseeeeneeeeeseeseseaeensneeeneeeessaesaseenenseaenes 1 How Many Microcontrollers Did You Use Today cccsccceceeeeeeeeeeeeceeeeeeseeeeesaees 1 The BASIC Stamp 2 Your New Microcontroller ccccccccceeeeeeeeeeeeeeeeeeeesneeeeeeseeees 1 Ama
273. p and convert them into positions held by the servo horn Figure 4 1 The Parallax Standard Servo 1 Plug 2 Cable 3 Horn 4 Case PARALLAX www parallax com CAUTION use only a Parallax Standard Servo for the activities in this text A Do not substitute a Parallax Continuous Rotation Servo as it may be quickly damaged by yp some of the circuits shown below Likewise we do not recommend using other brands or models of hobby servos which may not be rated for use with the voltage in these circuits Servo and LED Circuit Parts An LED circuit can be used to monitor the control signal the BASIC Stamp sends to the servo Keep in mind that the LED circuit is not required to help the servo operate It is just there to help see what s going on with the control signals 1 Parallax Standard Servo Chapter 4 Controlling Motion Page 105 1 Resistor 470 Q yellow violet brown 1 LED any color Building the Servo and LED Circuits It s really important to be careful when connecting a servo to your BASIC Stamp How you connect your servo depends on whether you are using the Board of Education Rev B Rev C or the HomeWork Board If you are using the Board of Education but you re not sure which Rev it is Figure 4 2 shows an example of the Rev label on the Board of Education Rev B X5 RevB lt Rev Label in Vss 15 14 13 12 oo oo Figure 4 2 Red Board of Si unnan fa
274. pushbutton is not pressed The LED circuit is not connected to Vdd It is an open circuit that cannot conduct current By pressing the pushbutton you close the connection between the terminals with conductive metal making a pathway for electrons to flow through the circuit Vdd Vdd 1 4 1 4 h lt Figure 3 4 2 3 2 3 Pushbutton Not Pressed and Pressed No 470 Q Current el Current Pushbutton circuit open left and Vss Vss Your Turn A Short Circuit Figure 3 5 shows a different circuit that will cause the LED to behave differently When the button is not pressed the LED stays on When the button is pressed the LED turns off The reason the LED turns off when the pushbutton is pressed is because current always follows the path of least resistance When the pushbutton is pressed terminals 1 4 and 2 3 have almost no resistance between them so all the current passes through the pushbutton short circuit instead of the LED y Build the circuit shown in Figure 3 5 y Repeat the tests you performed on the first pushbutton circuit you built with this new circuit Chapter 3 Digital Input Pushbuttons Page 75 Vdd Vdd Vin Vss m 1 4 P14 oong RER j Figure 3 5 ao EEE EIOCEEE LED that Gets 23 P8 g z C Shorted by P7 pan onne Pushbutton 470 Q oo LED Ke U ua O
275. r You will also program the BASIC Stamp to use these values to control the servo Parts and Circuit Same as Activity 1 Programming the BASIC Stamp to Receive Messages from Debug Programming the BASIC Stamp to send messages to the Debug Terminal is done using the DEBUG command Programming the BASIC Stamp to receive messages from the Debug Terminal is done using the DEBUGIN command When using this command you also have to declare one or more variables for the BASIC Stamp to store the information it receives Here is an example of a variable you can declare for the BASIC Stamp to store a value pulses VAR Word Later in the program you can use this value to store a number received by the DEBUGIN command DEBUGIN DEC pulses When the BASIC Stamp receives a numeric value from the Debug Terminal it will store it in the pulses variable The DEC formatter tells the DEBUGIN command that the characters you are sending will be digits that form a decimal number As soon as you hit the carriage return the BASIC Stamp will store the digits it received in the pulses variable as a decimal number then move on Although it is not included in the example program you can add a line to verify that the message was processed by the BASIC Stamp DEBUG CR You sent the value DEC pulses Example Program ServoControlWithDebug bs2 Figure 4 19 shows a close up view of the Transmit Windowpane in the Debug Terminal Your Transmit Windowpane ma
276. r base and collector Q2 The base controls the current passing through the transistor Q3 Increase or decrease the current allowed into the transistor s base E1 To solve this exercise look at TerminalControlledDigitalPot bs2 The first thing it does in the Initialization section is to set the tap to the lowest position This exact code is used in the solution below What s a Microcontroller Ch9Ex01 SetTapToZero bs2 Turn tap on digital pot all the way down to zero SSTAMP BS2 S PBASIC 2 5 DEBUG Program Running Pl Chapter 9 Electronic Building Blocks Page 279 UdPin CON 5 Set values of I O pins ClkPin CON 6 connected to CLK and U D counter VAR Byte I Counter for FOR NEXT LOW UdPin Set U D pin for Down FOR counter 0 TO 128 Set tap to lowest position PULSOUT ClkPin 5 PAUSE 1 NEXT Use the digital potentiometer circuit from Figure 9 6 p 269 and the photoresistor circuit from Figure 7 2 p 191 Vad Vad Vdd e AD5220 2200 Ky N 0 01 uF L 1 Vss Vss This solution is based on TerminalControlledDigitalPot bs2 except instead of being controlled by typing in the Debug Terminal it is controlled by reading the photoresistor A subroutine Read_Photoresistor reads the photoresistor using RCTIME as shown in Chapter 5 The reading from the photoresistor becomes the new tap setting and the original program does the work to set the tap The parts of the original progr
277. r the I O pin is changed from HIGH to INPUT As an input the I O pin has no effect on the circuit but it can sense high or low signals As soon as the I O pin releases the circuit the capacitor Page 148 What s a Microcontroller discharges as it feeds current through the resistor As the capacitor discharges the voltage across its terminals gets lower and lower decays INPUT 7 Back in the pushbutton chapter you used the BASIC Stamp to detect a high or low signal using the variables IN3 and IN4 At that time a high signal was considered Vdd and a low signal was considered Vss It turns out that a high signal is any voltage above 1 4 V Of course it could be up to 5 V Likewise a low signal is anything between 1 4 V and 0 V This Do LooPp checks P7 every 100 ms until the value of In7 changes from 1 to 0 which indicates that the capacitor voltage decayed below 1 4 V DO PAUSE 100 timeCounter timeCounter 1 DEBUG IN7 DEBUG DEC5 timeCounter CR CRSRUP CRSRUP LOOP UNTIL IN7 0 The result is then displayed and the program ends DEBUG CR CR CR The RC decay time was DEC timeCounter CR tenths of a second CR CR END Your Turn A Faster Circuit By using a capacitor that has roughly 1 3 the capacity to hold charge the time measurement for each resistor value that is used in the circuit will be reduced by 1 3 In Activity 3 you will use a capacitor that is 10 000 times smaller and the BASIC
278. r the READ keyword For example READ Notes noteLetter In this example Notes is the symbol parameter Q7 An octave is a group of 8 whole and 4 chromatic notes To get a given note in the next higher octave multiply the frequency by two Q8 SELECT CASE selects a variable or expression evaluates it on a case by case basis and executes different blocks of code depending on which case the variable s value fits into El This problem can be solved either by manually increasing each tone by 500 or by utilizing a FOR NEXT loop with a STEP value of 500 Utilizing FOR NEXT loop Manually increasing tone DEBUG Increasing alarm CR DEBUG Increasing Alarm CR PAUSE 100 PAUSE 100 FOR frequency 1500 TO 3000 STEP 500 FREQOUT 9 500 1500 FREQOUT 9 500 frequency PAUSE 500 PAUSE 500 FREQOUT 9 500 2000 NEXT PAUSE 500 FREQOUT 9 500 2500 PAUSE 500 FREQOUT 9 500 3000 PAUSE 500 E2 Modify the lines that check for the dotted note READ Dots index noteDot Chapter 8 Frequency and Sound Page 261 IF noteDot 1 THEN noteDuration noteDuration 3 2 Add a DEBUG command to the IF THEN Don t forget the ENDIF READ Dots index noteDot IF noteDot 1 THEN noteDuration noteDuration 3 2 DEBUG Dotted Note CR ENDIF P1 Use the piezospeaker circuit from Figure 8 2 p 220 pushbutton circuits from Figure 4 20 p 129 What s a Microcontroller Ch8Prj01 PushButtonToneGenerator bs2
279. ram also has a name initialization OUTH 300000000 Initialize 7 segment display DIRH 11111111 This next segment of code is called the main routine The main routine calls the Get Rc Time subroutine first Then it calls the Delay subroutine and after that it calls the Update Display subroutine Keep in mind that the program goes through the three subroutines as fast as it can over and over again DO Main routine GOSUB Get Rc Time GOSUB Delay GOSUB Update Display LOOP All subroutines are usually placed after the main routine The first subroutine s name is Get Rec Time and it takes the RC time measurement on the photoresistor circuit This subroutine has a PAUSE command that charges up the capacitor The Duration of this command is small because it only needs to pause long enough to make sure the capacitor is charged Note that the RcTIME command sets the value of the time variable This variable will be used by the second subroutine Subroutines Get_Rc_Time RC time subroutine HIGH 2 PAUSE 3 RCTIME 2 1 time Chapter 7 Measuring Light Page 213 RETURN The second subroutine s name is Delay and all it contains is a PAUSE command If you want to do some extra math on the value of the time variable before using it in the PAUSE command it would be appropriate to do that in this subroutine Delay PAUSE time RETURN The third subroutine is named Update Display The Lookup command in this subroutine co
280. rams will be much easier to work with if you organize them into smaller segments of code that do certain jobs PBASIC has some commands that you can use to make the program jump out of the main routine do a job and then return right back to the same spot in the main routine This will allow you to keep each segment of code that does a particular job somewhere other than your main routine Each time you need the program to do one of those jobs you can write a command inside the main routine that tells the program to jump to that job do it and come back when the job is done This process is called executing a subroutine Figure 7 11 shows an example of a subroutine and how it s used The command cosus Subroutine Name causes the program to jump to the Subroutine Name label When the program gets to that label it keeps running and executing commands until it gets to a RETURN statement Then the program goes back to command that comes after the GosuB command In the case of the example in Figure 7 11 the next command is DEBUG Next command Chapter 7 Measuring Light Page 207 DO GOSUB Subroutine Name DEBUG Next command LOOP Figure 7 11 How ack ti N Subroutines ubroutine_Name Work DEBUG This is a subroutine PAUSE 3000 RETURN What s a label A label is a name that can be used as a placeholder in your program GOSUB is one of the commands you can use to jump to a label Some others are GOTO IN ON GOTO and
281. res The example program you just finished introduced notes durations and rests It also used the duration of a whole note to determine tempo Cell phones that play music to let you know that somebody is calling have three features that were not supported by the previous example program e They play dotted notes e They determine the whole note duration from a value called tempo e They play notes from more than one octave The term dotted refers to a dot used in sheet music to indicate that a note should be played 1 times as long as its normal duration For example a dotted quarter note should last for the duration of a quarter note plus an eighth note A dotted half note lasts for a half plus a quarter note s duration You can add a data table that stores whether or not a note is dotted In this example a zero means there is no dot while a 1 means there is a dot Dots DATA OF lt 0 205 000 104s 104 GIG WjO5 04 05 420 O O O 1 0 Cell phones typically take the tempo for a song in beats per minute This is the same as saying quarter notes per minute BeatsPerMin CON 200 Figure 8 4 is a repeat of Figure 8 3 from page 228 It shows the 6 and 7 octaves on the piano keyboard These are the two octaves that sound the clearest when played by the piezospeaker Here is an example of a Data directive you will use in the Your Turn section to play notes from more than one octave using the Notes DATA directive
282. riculum though occasional circuit modifications are necessary for certain activities The BASIC Stamp What s a Microcontroller Kit includes the following items BASIC Stamp What s a Microcontroller Kit 90005 Parts and quantities subject to change without notice Parallax Part Description Quantity 555 28158 HomeWork Board with breadboard 1 28123 What s a Microcontroller Text 1 27000 Parallax CD includes software 1 800 00003 Serial cable 1 28122 What s a Microcontroller Parts Kit 1 700 00037 Rubber feet set of 4 1 A note to educators The HomeWork board is available separately in packs of 10 as an economical solution for classroom use costing significantly less than the Board of Education BASIC Stamp 2 module Please contact the Parallax Sales Team toll free at 888 512 1024 for quantity pricing BASIC Stamp HomeWork Board Ten Pack 28158 Parallax Part Description Quantity BASIC Stamp HomeWork Board BASIC Stamp 2 is built into the board 28158 10 Appendix C BASIC Stamp and Carrier Board Components and Functions Page 307 Appendix C BASIC Stamp and Carrier Board Components and Functions The BASIC STAMP 2 Figure C 1 shows a close up of Parallax Inc s BASIC Stamp 2 microcontroller module Its major components and their functions are indicated by labels BASIC Stamp 2 module Brownout detector shuts down t
283. ring Light Page 197 DO HIGH 2 PAUSE 100 RCTIME 2 1 time DEBUG DEC time CR LOOP Your Turn Adjusting the Display Span and Time Span have and buttons that you can click to increase or decrease the vertical and horizontal scales Span is to the left of the area that displays the graph and you can use it to adjust the maximum and minimum values displayed on the graph Time Span is below the graph and you can use it to change how many seconds worth of values plotted in the window Experiment with increasing and decreasing these values and note their effects on the how the graph appears If you have difficulty finding your plot you can always press and release the Reset button on your Board of Education or BASIC Stamp HomeWork Board to restore the default settings ACTIVITY 3 TRACKING LIGHT EVENTS One of the more useful features of the BASIC Stamp module s program memory is that you can disconnect the power but the program is not lost As soon as you reconnect power the program starts running again from the beginning Any portion of the program memory that is not used for the program can be used to store data This memory is especially good for storing data that you do not want the BASIC Stamp to forget even if power is disconnected and reconnected The chip on the BASIC Stamp that stores program memory and data is shown in Figure 7 7 This chip is called an EEPROM EEPROM stands for electrically erasable pr
284. rk and it has been reorganized into labeled sections y Verify that the program still works the same as PasswordChecker bs2 V Examine how the DO LOOP UNTIL code block was placed into a subroutine Chapter 10 Running the Whole Show Page 295 U anen Tigle asssassosce sso soe n What s a Microcontroller ReusablePasswordChecker bs2 Check password entered in Debug Terminal s Transmit Windowpane SSTAMP BS2 PBASIC 2 5 Password DATA pass INStoOne sUSeCheL pacswondshonren index VAR Nib Index variable temp VAR Byte L rores canicHlicmchicias userEntry VAR Byte 5 Store user entered password Initialization Routine GOSUB Check_Password There is no main routine in this program DEBUG CR All Done END Subroutine Check for Correct Password Check_Password DO DEBUG Enter password User instructions DEBUGIN STR userEntry 5 Get user input password FOR index 0 TO 4 Check array against DATA READ Password index temp Get next password char IF temp lt gt userEntry index THEN EXIT Compare to user input NEXT U eai skis nOn xe pbteull IF index lt gt 5 THEN If exit then index not equal DEBUG CR Password not correct CR to 5 and pass is not correct ENDIF LOOP UNTIL index 5 Only get out of loop when Y Index 5 Page 296 What s a Microcontroller DEBUG CR Pas
285. rn clockwise to about the 2 o clock position for about three seconds After that the servo seconds will hold its center position which is about 12 o clock for about three Figure 4 14 Servo Horn Motion 10 o clock left 2 o clock middle 12 o clock right What if my servo is different We recommend that you use a Parallax Standard Servo for these activities There are lots of different servos and many will respond differently to the signals that TestServo bs2 sends Another brand of servo might only rotate to 11 o clock then 1 o clock or maybe to 9 o clock and then 3 o clock It might even rotate the opposite direction and start in the clockwise direction before it goes counterclockwise But if your servo is rated for use with a 9 V battery and the motion is easy to observe and consistent it will work for these activities You can modify the example programs to get the servo to behave the way you want Enter ServoTest bs2 into the BASIC Stamp Editor Connect power to your Board of Education or Home Work Board Run the program Chapter 4 Controlling Motion Page 115 Observe the servo turns at each of the three steps in the program and record where the horn is really pointing V Re run the program and verify that the LED flickers dimly It should be brightest when the BASIC Stamp sends the 10 o clock signal and dimmest when the BASIC Stamp sends the 2 o clock signal This is because the LED
286. rogram DoReMiFaSolLaTiDo bs2 Enter and run DoReMiFaSolLaTiDo bs2 What s a Microcontroller DoReMiFaSolLaTiDo bs2 Send an octave of half second tones using a piezoelectric speaker SSTAMP BS2 SPBASIC 2 5 soltege Tone Note DEBUG Do CR FREQOUT 9 500 1047 C6 DEBUG MUR Cee sun CR RERE Wie S00 AN5 D6 DEBUG Mi CR FREQOUT 9 500 1319 E6 DEBUG Ub ciel ECR RERE OU Es Iss OO S96 1 F6 DEBUG Soli RS BREOOUT 9 500 1565 GG DEBUG La CR FREQOUT 9 500 1760 A6 Page 230 What s a Microcontroller DEBUG Ti CR FREQOUT 9 500 1976 B6 DEBUGCHLDPON U Ch EERE OUT IF 00702 0 98 Wee END Your Turn Sharp Flat Notes V Use the frequencies shown in Figure 8 3 to add the five sharp flat notes to DoReMiFaSolLaTiDo bs2 y Modify your program so that it plays the next octave up Hint Save yourself some typing and just use the 2 operation after each Freq1 argument For example FREQOUT 9 500 1175 2 will give you D7 the D note in the 7 octave Storing and Retrieving Sequences of Musical Notes A good way of saving musical notes is to store them using the BASIC Stamp module s EEPROM Although you could use many WRITE commands to do this a better way is to use the DATA directive This is the syntax for the DATA directive Symbol DATA Word Dataltem Word Dataltem Here is an example of how to use the DATA directive to store the characters that co
287. rogram and observe the effect ACTIVITY 3 DISPLAYING DIGITS If you include the decimal point there are eight different BASIC Stamp I O pins that send high low signals to the 7 segment LED display That s eight different HIGH or Low commands just to display one number If you want to count from zero to nine that would be a huge amount of programming Fortunately there are special variables you can use to set the high and low values for groups of I O pins In this activity you will use 8 digit binary numbers instead of HIGH and Low commands to control the high low signals sent by BASIC Stamp I O pins By setting special variables called DIRH and ouTH equal to the binary numbers you will be able to control the high low signals sent by all the I O pins connected to the 7 segment LED display circuit with a single PBASIC command Chapter 6 Digital Display Page 175 8 bits A binary number that has 8 digits is said to have 8 bits Each bit is a slot where you an can store either a 1 or a 0 1 a byte is a variable that contains 8 bits There are 256 different combinations of zeros and ones that you can use to count from 0 to 255 using 8 bits This is why a byte variable can store a number between 0 and 255 Parts and Circuit for Displaying Digits Same as previous activity Programming On Off Patterns Using Binary Numbers In this activity you will experiment with the variables DIRH and OUTH DIRH is a variable that con
288. romAddress VAR Byte DEBUG Starting measurements CR CR Measurement Value CR CLR pe fe ee ae irae he ae es ug tpt re CR PAUSE 1000 FOR eepromAddress 0 TO 58 STEP 2 HIGH 2 PAUSE 5000 RCTIME 2 1 time DEBUG DEC2 eepromAddress DEC time CR WRITE eepromAddress Word time NEXT DEBUG All done Now run CR ReadLightMeasurementsFromEeprom bs2 END How StoreLightMeasurementsInEeprom bs2 Works The For NEXT loop that measures the RC time values and stores them to EEPROM has to count in steps of 2 because word values are written into the EEPROM FOR eepromAddress 0 to 58 STEP 2 The RCTIME command loads the time measurement into the word size time variable RCTIME 2 1 time The time variable is stored at the address given by the current value of the eepromAddress variable each time through the loop Remember the eepromaddress variable is incremented by two each time through the loop because a Word variable takes up two bytes The address for a WRITE command is always in terms of bytes WRITE eepromAddress Word time NEXT Page 202 What s a Microcontroller Programming Data Retrieval To retrieve these values from EEPROM you can use the READ command The syntax for the READ command is READ Location WORD Data Item While the WRITE command can use either a constant or a variable the READ command s DataItem argument must be a variable because it has to store the value fetched from the EEPROM
289. rrespond to musical notes Notes DATA wou wou wgu 1G 7 A A A A G You can use the READ command to access these characters The letter C is located at address Notes 0 and a second letter C is located at Notes 1 Then there s a letter G at Notes 2 and so on For example if you want to load the last letter G into a byte variable called noteLetter use the command READ Notes 6 noteLetter You can also store lists of numbers using the DATA directive Frequency and duration values that the BASIC Stamp uses for musical notes need to be stored in word variables because they are usually greater than 255 Here is how to do that with a Data directive Frequencies DATA Word 2093 Word 2093 Word 3136 Word 3136 Word 3520 Word 3520 Word 3136 Chapter 8 Frequency and Sound Page 231 Because each of these values occupies two bytes accessing them with the read command is different from accessing characters The first 2093 is at Frequencies 0 but the second 2093 is located at Frequencies 2 The first 3136 is located at Frequencies 4 and the second 3136 is located at Frequencies 6 e The values in the Frequencies DATA directive correspond with the musical notes in wy the Notes DATA directive Here is a FOR NEXT loop that places the Notes DATA into a variable named noteLetter then it places the Frequencies DATA into a variable named noteFreq FOR index 0 to 6 READ
290. rted to digits by subtracting 0 which is the same as subtracting 48 The first time this subroutine is calles Cereri le 0 Page 254 What s a Microcontroller RETURN C Iie 0 Than Sep Cererile Cs Subroutine Find Index of Note ProcessNote Set index value for lookup of note frequency based on READ RTTTL File counter char nete thanacter TE tpt SELECT char Wr aljayokepic alfsy GEE HEN fexey Pej CASE p read character values in index 0 DATA table and find match counter counter 1 Record index value when CASE a TO g match is found If next EFOR iG exc ATO TZ char is a sharp add READ Notes index noteLetter 1 to the index value to IF noteLetter char THEN EXIT increase the index and NEXT frequency by 1 notch counter counter 1 As with other subroutines READ RTTTL File counter char increment counter for each SELECT char character that is processed CASE index index 1 counter counter 1 ENDSELECT ENDSELECT RETURN Subroutine Determine Note Duration ProcessDuration Check to see if characters i acon abe Ae Ae hp ale xe SAY READ RTTTL File counter char OEE yee then convert from ASCII character to a value SELECT char by subtracting 48 In the CAS eS T ee a La case of 16 or 32 multiply duration char 48 by 10 and add the next counter counter
291. s 9 V battery clip ie Header for connecting Filter capacitors for f oa power Vdd Vin Vss to 5 VDC regulators on ma l eel aa ee circuits on the breadboard Board of Education ES pi and BASIC Stamp amen i Breadboard rows are connected horizontally separated by the trough Serial port connector for downloading PBASIC mu programs and debug terminal runtime communication a e lt HHH Pol lie Header for connecting BASIC Stamp I O pins to circuits on the Socket for any 24 pin BASIC Stamp module Power indicator light Three position switch 0 power OFF 1 power ON servo ports OFF 2 power ON servo ports ON Reset button may be pressed and released to restart your BASIC Stamp program Figure C 2 Parallax Inc s Board of Education Rev C Carrier Board for BASIC Stamp Microcontroller Modules Appendix C BASIC Stamp and Carrier Board Components and Functions Page 309 The BASIC Stamp HomeWork Board Parallax Inc s BASIC Stamp HomeWork Board project platform is shown in Figure C 3 Its major components and their functions are indicated by labels Serial port connector for downloading PBASIC programs and debug terminal runtime communication Header for connecting power Vdd Vin Wss to circuits on the breadboard 9 V battery clip Breadboard rows are Power indicator light connected horizontally Stays on when power separated by the trough is connected and a pr
292. s A 3 t man an won e The same as This DATA directive is the same as Password DATA p a s ngn oye SP eee You will need a few variables for storing other values in the program index VAR Nib temp VAR Byte If you are using a five character password there is a special kind of variable declaration called an array declaration that you use to declare five variables with the same name userEntry VAR Byte 5 Now you have five byte variables named userEntry userEntry 0 userEntry 1 userEntry 2 userEntry 3 and userEntry 4 The DEBUGIN command has a formatter called str that automatically loads characters into an array For example you can use DEBUGIN STR userEntry 5 If you type five characters in the Debug Terminal s Transmit Windowpane the first will get placed in userEntry 0 the second will get placed in userEntry 1 etc There is a PBASIC keyword called Exit that you can use to break out of a loop To check a password you can use an IF THEN statement with an EXIT command to cause the loop to end early if not all the characters are identical When the loop ends early it means that index has not counted all the way up to five which in turn means the password was not correct FOR index 0 TO 4 READ Password index temp IF temp lt gt userEntry index THEN EXIT NEXT IF index lt gt 5 THEN DEBUG CR Password not correct CR ENDIF Chapter 10 Running the Whole
293. s the LED less bright Repeat using the 1 kQ resistor then the 2 KQ resistor checking the change in brightness each time Appendix F More about Electricity Page 321 Vdd in 5S X3 Vdd R R R R i P15 1 2 3 4 P14 oowoo P13 P12 R P11 Figure F 1 ia LED Current Monitor R 2200 B X LED R 470Q P6 R 1 kQ 2 R 2kQ P3 P2 Vss H X2 If you are using a 9 V battery you can also compare the brightness of a different voltage source Vin Vin is connected directly to the 9 V battery s terminal and Vss is connected directly to the battery s negative terminal Vdd is called regulated 5 V That s about half the voltage of the 9 V battery Ifyou are not using a 9 V battery stop here and skip to the Calculating the Current section below Otherwise continue V Start with the circuit shown in Figure F 1 but use a 1 KQ resistor V Make a note of how bright the LED is V Disconnect power V Modify the circuit by disconnecting the resistor lead from Vdd and plugging it into Vin When you plug the power back in is the LED brighter How much brighter DO NOT try the Vin experiment with a 220 or 470 Q resistor it will supply the LED with ys more current than it is rated for Calculating the Current The BASIC Stamp Manual ha
294. s a pull up or a pull down The DEBUG statement will display the button state either way DO DEBUG IN6 PAUSE 250 LOOP First a button was added for the second player wired to Stamp I O pin P4 The schematic is based on Figure 3 14 on page 90 Chapter 3 Digital Input Pushbuttons Page 99 Vdd Vdd P15 Mi S ol P4 P3 220 Q 220 Q 10 kQ 10 kQ A NS P14 4709 Vss Vss Snippets from the solution program are included below but keep in mind solutions may be coded a variety of different ways However most solutions will include the following modifications Use two variables to keep track of two player s times timeCounterA VAR Word Time score of player A timeCounterB VAR Word Time score of player B Change instructions to reflect two pushbuttons DEBUG Press and hold pushbuttons CR DEBUG buttons down again CR CR Wait for both buttons to be pressed before turning LED red by using the AND operator LOOP UNTIL IN3 1 AND IN4 1 Wait for both buttons to be released to end timing again using the AND operator LOOP UNTIL IN3 0 AND IN4 0 Add logic to decide which player s time is incremented IF IN3 1 THEN timeCounterA timeCounterA 1 ENDIF IF IN4 1 THEN timeCounterB timeCounterB 1 ENDIF Change time display to show times of both players DEBUG Player A Time DEC timeCounterA ms CR DEBUG Player B Time DEC timeCounterB ms CR CR Add
295. s how Table 2 1 and Figure 2 3 can be used to figure out a resistor value by proving that yellow violet brown is really 470 Q Page 40 What s a Microcontroller e The first stripe is yellow which means the leftmost digit is a 4 e The second stripe is violet which means the next digit is a 7 e The third stripe is brown Since brown is 1 it means add one zero to the right of the first two digits Yellow Violet Brown 4 7 0 Introducing the LED A diode is a one way current valve and a light emitting diode LED emits light when current passes through it Unlike the color codes on a resistor the color of the LED usually just tells you what color it will glow when current passes through it The important markings on an LED are contained in its shape Since an LED is a one way current valve you have to make sure to connect it the right way or it won t work as intended Figure 2 4 shows an LED s schematic symbol and part drawing An LED has two terminals One is called the anode and the other is called the cathode In this activity you will have to build the LED into a circuit paying attention to make sure the leads connected to the anode and cathode are connected to the circuit properly On the part drawing the anode lead is labeled with the plus sign On the schematic symbol the anode is the wide part of the triangle In the part drawing the cathode lead is the unlabeled pin and on the schematic symbol the cathode is
296. s new ways to adjust an LED s brightness BASIC Stamp Editor Help File PBASIC 2 5 Version 2 0 Parallax Inc 2003 The PBASIC 2 5 Help File has information on Do Loop which is new to PBASIC 2 5 and not included in the BASIC Stamp Manual You can find this information by clicking the book icon on your BASIC Stamp Editor task bar then selecting PBASIC Reference from the menu in the left sidebar window This will open the PBASIC Command Reference alphabetical listing in the main window Detailed information can be found by clicking on each command Chapter 3 Digital Input Pushbuttons Page 71 Chapter 3 Digital Input Pushbuttons FOUND ON CALCULATORS HAND HELD GAMES AND APPLIANCES How many devices with pushbuttons do you use on a daily basis Here are a few examples that might appear in your list computer mouse calculator microwave oven handheld remote handheld games and VCR In each device there is a microcontroller scanning the pushbuttons and waiting for the circuit to change When the circuit changes the microcontroller detects the change and takes action By the end of this chapter you will have experience with designing pushbutton circuits and programming the BASIC Stamp to monitor them and take action when changes occur RECEIVING VS SENDING HIGH AND LOW SIGNALS In Chapter 2 you programmed the BASIC Stamp to send high and low signals and you used LED circuits to display these signals Sending high and lo
297. s some rules about how much current it can supply to circuits If you don t follow these rules you may end up damaging your BASIC Stamp Page 322 What s a Microcontroller The rules have to do with how much current an I O pin is allowed to deliver and how much current a group of I O pins is allowed to deliver Current Rules for BASIC Stamp I O Pins e An I O pin can source 20 mA In other words if you send the HIGH signal to an I O pin it should not supply the LED circuit with more than 20 mA A i If you rewire the LED circuit so that the BASIC Stamp makes the LED turn on yy when you send the Low command an I O pin can sink up to 25 mA e PO through P7 can only source up to 20 mA Likewise with P8 through P15 If you have lots of LED circuits you will need larger resistors so that you don t draw too much current If you know how to calculate how much current your circuit will use then you can decide if it s OK to make your LEDs glow that brightly Every electronic component has rules for what it does with voltage resistance and current For the light emitting diode the tule is a value called the diode forward voltage For the resistor the rule is called Ohm s Law You need to figure out how much current your LED circuit is using There are also rules for how current and voltage add up in circuits These are called Kirchoff s Voltage and Current Laws Appendix F More about Electricity Pag
298. s the cursor back up to the previous line This causes the new value of counter to be printed over the old value each time through the loop The second FOR NEXT loop counts downwards from 1000 back to 500 in steps of 20 The counter Variable is also used as an argument for the PULSOUT command in this example so the servo horn rotates clockwise FOR counter 1000 TO 500 STEP 20 PULSOUT 14 counter Page 128 What s a Microcontroller PAUSE 7 DEBUG DEC5 counter CR CRSRUP NEXT Your Turn Adjusting the Velocities y Try different STEP values to make the servo turn at different rates V Re run the program after each modification V Observe the effect of each new sTEP value on how fast the servo horn turns y Experiment with different PAUSE command Duration values between 3 and 12 to find the value that gives the servo the smoothest motion for each new STEP value ACTIVITY 4 PUSHBUTTON CONTROLLED SERVO In this chapter you have written programs that make the servo go through a pre recorded set of motions and you have controlled the servo using the Debug Terminal You can also program the BASIC Stamp to control the servo based on pushbutton inputs In this activity you will e Build a circuit for a pushbutton controlled servo e Program the BASIC Stamp to control the servo based on the pushbutton inputs When you are done you will be able to push one button to get the BASIC Stamp to rotate the servo in one directio
299. s2 Indicate light level using 7 segment display SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running index VAR Nib time VAR Word OUTH 00000000 DIRH ES DO GOSUB Get_Rc_ Time GOSUB Delay GOSUB Update Display LOOP Get_Rc_Time HDGH lt 2 PAUSE 3 RCTIME 2 1 time RETURN Delay PAUSE time RETURN Update Display IF index 6 THEN index 0 i BAFG CDE LOOKUP index 01000000 10000000 00000100 00000010 00000001 00100000 OUTH index index 1 RETURN Chapter 7 Measuring Light Page 211 Variable declarations Initialize 7 segment display Main routine Subroutines RC time subroutine Delay subroutine Display updating subroutine Page 212 What s a Microcontroller How LightMeter bs2 Works The first two lines of the program declare variables It doesn t matter whether these variables are used in subroutines or the main routine it s always best to declare variables and constants at the beginning of your program Since this is such a common practice this section of code has a name variable declarations This name is shown in the comment to the right of the first variable declaration index VAR Nib Variable declarations time VAR Word Many programs also have things that need to get done once at the beginning of the program Setting all the 7 segment I O pins low and then making them outputs is an example This section of a PBASIC prog
300. se e You can get similar hints to find out what the other buttons do by pointing at them too LL Figure 1 41 ra E gt R BASIC Stamp Editor Shortcut Buttons Run How FirstProgram bs2 Works The first two lines in the example are called comments A comment is a line of text that gets ignored by the BASIC Stamp Editor because it s meant for a human reading the program not for the BASIC Stamp module In PBASIC everything to the right of an apostrophe is normally considered to be a comment by the BASIC Stamp Editor The first comment tells which book the example program is from and the program s filename The second comment contains a handy one line description that explains what the program does What s a Microcontroller FirstProgram bs2 BASIC Stamp sends message to Debug Terminal Although comments are ignored most of the time the BASIC Stamp Editor does search through comments for special directives Every program in this text will use these two directives SSTAMP BS2 PBASIC 2 5 The first directive is called the STAMP Directive and it tells the BASIC Stamp Editor that you will be downloading the program specifically to a BASIC Stamp 2 module The second directive is called the PBASIC directive and it tells the BASIC Stamp Editor that you are using version 2 5 of the PBASIC programming language Note that these compiler directives are enclosed in braces not parentheses You should
301. se capacitors incorrectly can damage it In some circuits connecting this type of capacitor incorrectly and then connecting power can cause it to rupture or even explode Figure 5 7 3300 uF Capacitor Schematic Symbol and Part Drawing T 3300 uF Pay careful attention to the leads and how they connect to the Positive and Negative Terminals Page 144 What s a Microcontroller Resistance and Time Parts 1 Capacitor 3300 uF 1 Capacitor 1000 uF 1 Resistors 220 Q red red brown 1 Resistor 470 Q yellow violet brown 1 Resistor 1 kQ brown black red 1 Resistor 2 kQ red black red 1 Resistor 10 kQ brown black orange w A Recommended Equipment Safety goggles or safety glasses Building and Testing the Resistance Capacitance RC Time Circuit Figure 5 8 shows the circuit schematic and Figure 5 9 shows the wiring diagram for this activity You will be taking time measurements using different resistor values in place of the resistor labeled Rj SAFETY Always observe polarity when connecting the 3300 uF capacitor Remember the negative terminal is the lead that comes out of the metal canister closest to the stripe with a negative sign Use Figure 5 7 to identify the and terminals Your 3300 uF capacitor will work fine in this experiment so long as you make sure that the positive and negative terminals are connec
302. second program that retrieves the values from EEPROM and displays them in the Debug Terminal Programming Long Term Data Storage The WRITE command is used to store values in the EEPROM and the READ command is used to retrieve those values The syntax for the WRITE command is WRITE Location WORD Data Item For example if you want to write the value 195 to address 7 in the EEPROM you could use the command WRITE 7 195 Word values can be anywhere between 0 and 65565 while byte values can only contain numbers between 0 and 255 A word value takes the space of two bytes If you want to write a word size value to EEPROM you have to use the optional Word modifier Be careful though Since a word takes two bytes you have to skip one of the byte size addresses in EEPROM before you can write another word Let s say you need to save Page 200 What s a Microcontroller two word values to EEPROM 659 and 50012 You could start at address 8 but you will have to write the second value to address 10 WRITE 8 Word 659 WRITE 10 Word 50012 Is it possible to write over the program Yes and if you do the program is likely to either start behaving strangely or stop running altogether Since the PBASIC program tokens reside in the highest addresses in the EEPROM it s best to use the lowest Address values for storing numbers with the WRITE command How do I know if the Address I m using is too large You can use the memory map to fig
303. ses no delay but it varies both the duration and frequency By using FOR NEXT loops to rapidly change the frequency and duration you can get some interesting sound effects When one FOR NEXT loop executes inside another one it is called a nested loop Here is how the nested Fror NExT loop shown below works The Page 224 What s a Microcontroller duration variable starts at 15 then the frequency loop takes over and sends frequencies of 2000 then 2020 then 2040 and so on up through 2500 to the piezo speaker When the frequency loop is finished the duration loop has only repeated one of its 15 passes So it subtracts one from the value of duration and repeats the frequency loop all over again FOR duration 15 TO 1 FOR frequency 2000 TO 2500 STEP 15 FREQOUT 9 duration frequency NEXT NEXT Example Program NestedLoops bs2 To better understand how nested For NEXT loops work NestedLoops bs2 uses the DEBUG command to show the value of a much less complicated version of the nested loop used in ActionTones bs2 y Enter and run NestedLoops bs2 y Examine the Debug Terminal output and verify how the duration and frequency arguments change each time through the loop What s a Microcontroller ActionTones bs2 Demonstrate how different combinations of pause duration and frequency can be used to make sound effects SSTAMP BS2 SPBASIC 2 5 duration VAR Word frequency VAR Word DEBUG Alarm CR PAUSE 100
304. set the tap to 125 open pos 126 and close pos 125 set U D low then apply a pulse to CLK If you want to set the tap to Pos 127 set U D high and apply 2 pulses If you want to bring the tap down to 1 set U D low and apply 126 pulses This next example program uses the Debug Terminal to ask you which tap setting you want Then it decides whether to set the U D pin high or low and applies the correct number of pulses to move the tap from its old setting to the new setting With the exception of EEPROM Data the next example program also has all the sections you could normally expect to find in an application program e Title comments that include the filename of a program its description and the Stamp and PBASIC directives e EEPROM Data The pata declarations used by the program e I O Definitions constant declarations that define I O pin numbers e Constants constant declarations that define other values used in the program e Variables variable declarations e Initialization a routine that gets the program started on the right foot In this next program the potentiometer s tap needs to be brought down to zero e Main the routine that handles the primary jobs the program has to do e Subroutines the segments of code that do specific jobs either for each other or in this case for the main routine Example Program TerminalControlledDigtialPot bs2 You can use this example program and the Deb
305. shbuttons and updates the display It also monitors sensors inside the oven and switches devices that turn the heating elements on and off Figure 6 1 Digital Clock 7 Segment Display on Oven Door Each of the three digits in Figure 6 1 is called a 7 segment display In this chapter you will program the BASIC Stamp to display numbers and letters on a 7 segment display WHAT S A 7 SEGMENT DISPLAY A 7 segment display is rectangular block of 7 lines of equal length that can be lit selectively to display digits and some letters A very common form is the 7 segment LED display a package with a rectangular block of 7 LEDs Figure 6 2 shows a part drawing of the 7 segment LED display you will use in this chapter s activities It has one additional LED a dot that can be used as a decimal point Each of the segments A through G and the dot contains a separate LED which can be controlled individually Most of the pins have a number along with a label that corresponds with one of the LED segments Pin 5 is labeled DP which stands for decimal point Pins 3 and 8 are labeled common cathode and they will be explained when the schematic for this part is introduced Page 166 What s a Microcontroller Common Cathode 109876 Figure 6 2 7 Segment LED Display Part Drawing and Pin Map 12345 l Common Cathode Pin Map Figure 6 2 is an example of a pin map A pin map contains useful information that helps you connec
306. should not glow green Vdd Vin Vs X3 i P15 i P14 AOwOO P13 Figure 2 9 P12 LED Off Circuit P11 P10 P9 Schematic left and 470 Q Be wiring diagram right X LED pe P5 P4 P3 Vss Vss PO x2 ACTIVITY 2 ON OFF CONTROL WITH THE BASIC STAMP In Activity 1 two different circuits were built and tested One circuit made the LED emit light while the other did not Figure 2 10 shows how the BASIC Stamp can do the same thing if you connect an LED circuit to one if its I O pins In this activity you will connect the LED circuit to the BASIC Stamp and program it to turn the LED on and off Chapter 2 Lights On Lights Off Page 47 You will also experiment with programs that make the BASIC Stamp do this at different speeds Figure 2 10 south ge avn BASIC Stamp oN LM Switching VDD 5V es The BASIC p 2a Stamp can be programmed to internally connect the LED circuit s input to Vdd or Vss Y pi JE et el Gel el Gl et There are two big differences between changing the connection manually and having the BASIC Stamp do it First the BASIC Stamp doesn t have to cut the power when it chan
307. sword is correct Program can move on when password is correct RETURN Return when pass is correct Advanced Topic Your Turn Combining the two Programs Now that both TerminalOperatedSensorArray bs2 and ReusablePasswordChecker bs2 have both been tested the task is to combine the two The final program should check your password before allowing you to choose which sensor to read using the Debug Terminal y You can open both programs ReusablePasswordChecker bs2 and TerminalOperatedSensorArray bs2 in the BASIC Stamp Editor y Save TerminalOperatedSensorArray bs2 as PasswordedSensorTerminal bs2 You will need to tab between each program while copying sections from ReusablePasswordChecker bs2 and pasting them into PasswordedSensorTerminal bs2 y Copy the Password DATA directive including the commented heading with the dashed line from ReusablePasswordChecker bs2 into PasswordedSensorTerminal bs2 just before the 1 0 Definitions section y Copy and paste the variable declarations from ReusablePasswordChecker bs2 into PasswordedSensorTerminal bs2 These variable declarations are added to the ones in PasswordedSensorTerminal bs2 so don t worry about copying and pasting the commented Variables heading y Copy the Initialization section including the commented heading from ReusablePasswordChecker bs2 and paste it between the Variables section and the Main Routine in PasswordedSensorTerminal bs2 y Copy the entire Subroutine sect
308. t s say you turn the potentiometer s knob one step clockwise The LED will get only slightly brighter This would be the same as sending a high signal to the AD5220 s U D pin and sending one pulse high low high to the CLK pin HIGH 5 PULSOUT 6 1 Imagine next that you turn your manual potentiometer 3 steps counterclockwise The LED will get a little bit dimmer This would be the same as sending a low signal to the U D pin on the AD5220 and sending three pulses to the CLK pin LOW 5 FOR counter 1 TO 3 PULSOUT 6 1 PAUSE 1 NEXT Chapter 9 Electronic Building Blocks Page 271 Imagine next that you turn the potentiometer all the way clockwise That s the same as sending a high signal to the AD5220 s U D pin and sending 65 pulses to the CLK pin Now the LED should be shining brightly HIGH 5 FOR counter 1 TO 65 PULSOUT 6 1 PAUSE 1 NEXT Finally imagine that you turn your manual potentiometer all the way counterclockwise The LED should emit no light That s the same as sending a low signal to the U D pin and applying 128 pulses to the CLK pin LOW 5 FOR counter 0 TO 127 PULSOUT 6 1 PAUSE 1 NEXT Example Program DigitalPotUpDown bs2 This example program adjusts the potentiometer up and down from one end of its range to the other causing the LED to get gradually brighter then gradually dimmer V Enter and run DigitalPotUpDown bs2 What s a Microcontroller DigitalPotUpDown bs2 Sweep digital pot
309. t s time to start counting to track how long until the player releases the button The timeCounter variable is set to zero then another DO LOOP with an UNTIL condition starts repeating itself It repeats itself until the player releases the button IN3 0 Each time through the loop the BASIC Stamp delays for 1 ms using PAUSE 1 and it also adds 1 to the value of the timeCounter variable timeCounter 0 Set timeCounter to zero DO Nested loop count time PAUSE 1 timeCounter timeCounter 1 LOOP UNTIL IN3 0 until pushbutton is released The bi color LED is turned off LOW 14 The results are displayed in the Debug Terminal DEBUG Your time was DEC timeCounter ome CR CR To play again hold the CR Page 94 What s a Microcontroller button down again CR CR The last statement in the program is Loop which sends the program back to the very first DO statement Your Turn Revising the Design The marketing department gave your prototype to some game testers When the game testers were done the marketing department came back to you with an itemized list of three problems that have to be fixed before your prototype can be built into the game controller y Save ReactionTimer bs2 under a new name like ReactionTimerY ourTurn bs2 The itemized list of problems and their solutions are discussed below Item 1 When a player holds the button for 30 seconds his score is act
310. t a part to other circuits Pin maps usually show a number for each pin a name for each pin and a reference Take a look at Figure 6 2 Each pin is numbered and J _ the name for each pin is the segment letter next to the pin The reference for this part is its overall appearance You know by looking at the top of the display that pin 1 is closest to the lower left corner of the display Other parts have more subtle references such as the flat spot on a regular LED s case Figure 6 3 shows a schematic of the LEDs inside the 7 segment LED display Each LED anode is connected to an individual pin All the cathodes are connected together by wire inside the part Because all the cathodes share a common connection the 7 segment LED display can be called a common cathode display By connecting either pin 3 or pin 8 of the part to Vss you will connect all the LED cathodes to Vss Chapter 6 Digital Display Page 167 Figure 6 3 7 Segment Schematic ACTIVITY 1 BUILDING AND TESTING THE 7 SEGMENT LED DISPLAY In this activity you will manually build circuits to test each segment in the display 7 Seqment LED Display Test Parts 1 7 segment LED display 5 Resistors 1 kQ brown black red 5 Jumper wires 7 Seqment LED Display Test Circuits V With power disconnected from your Board of Education or HomeWork Board build the circuit shown in Figure 6 4 and Figure 6 5 V Reconnect power and verify that the A se
311. t activity Figure 10 3 Adding a Second Pushbutton Circuit to the Project Vin Vss Vdd ms P4 220 Q 10 kQ Chapter 10 Running the Whole Show Page 285 ACTIVITY 2 BUILDING AND TESTING EACH RC TIME CIRCUIT Now that the two pushbutton circuits are built and tested you can move on to the RC time circuits Extra Parts for Potentiometer and Photoresistor Circuits 2 Resistors 220 Q red red brown 2 Capacitors 0 1 uF 4 Jumper wires 1 Photoresistor 1 Potentiometer 10 kQ Building the Potentiometer Circuit V Add the potentiometer circuit shown in Figure 10 4 to the project Figure 10 4 Adding a Potentiometer Circuit of P7 y 2202 ya l Pot l raid 0 1 uF oo wooo oo gt sooNg A e woOo Vss sew ooco Foog Dooe woowo Testing the Potentiometer Circuit You can test this circuit using ReadPotWithRcTime bs2 This program was first used in Chapter 5 to read the potentiometer circuit Example Program ReadPotWithRcTime bs2 y Enter and run the ReadPotWithRcTime bs2 Page 286 What s a Microcontroller y Verify t
312. t emit light when you connect power The resistor just resists the flow of current There is no backwards or forwards for a resistor a O Vdd i te gt poboo P13 Figure 2 6 470 Q P12 LED On P11 P10 P9 Schematic left and X LED its Wiring Diagram right Vss Reconnect power to your Board of Education or HomeWork Board Check to make sure your green LED is emitting light It should glow green Vdd Vin 5S X3 X2 If your green LED does not emit light when you connect power to the board N N Some LEDs are brightest when viewed from above Try looking straight down onto the dome part of the LED s plastic case from above If the room is bright try turning off some of the lights or use your hands to cast a shadow on the LED If you still do not see any green glow try these steps J Double check to make sure your cathode and anode are connected properly If not simply remove the LED give it a half turn and plug it back in It will not hurt the LED if you plug it in backwards it just doesn t emit light When you have it plugged in the right direction it should emit light Page 44 What s a Microcontroller V Double check to make sure you built your circuit exactly as shown in Figure 2 6 Ifyou are us
313. t s a Microcontroller Selecting which Code Block to Execute on a Case by Case Basis The SELECT CASE statement is probably the best programming tool for recognizing characters or values Keep in mind that this is one of the tools used to convert an RTTTL ringtone into musical notes In general SELECT CASE is used to e Select a variable or expression e Evaluate that variable or expression on a case by case basis e Execute different blocks of code depending on which case that variable s value fits into Here is the syntax for SELECT CASE SELECT expression CASE condition s statement s ENDSELECT You can try the next two example programs to see how SELECT cASE works SelectCaseWithValues bs2 takes numeric values you enter into the Debug Terminal and it tells you the minimum variable size you will need to hold that value SelectCase WithCharacters bs2 tells you whether the character you entered into the Debug Terminal is upper or lower case a digit or punctuation Remember to use the upper Windowpane in the Debug Terminal to transmit the characters you type to the BASIC Stamp The Transmit and Receive Windowpanes are shown in Figure 8 5 Y Debug Terminal 1 e215 x Com Port Baud Rate Parity Windowpanes pani roves a a Figure 8 5 oo FX_ DSR_ CTS Sending Messages Transmit gt to the BASIC Stamp Click the Transmit upper Windowpane and enter the value or characters you want to transmit to the BASIC Stamp R
314. te FREQOUT 9 noteDuration noteFreq Each time through the main loop the index value must be increased by one When the main loop gets back to the beginning the first thing the program does is read the next note using the index variable index index 1 LOOP Your Turn Experimenting with Tempo and a Different Tune The length of time that each note lasts is related to the tempo You can change the tempo by adjusting the WholeNote constant If you increase it to 2250 the tempo will decrease and the song will play slower If you increase it to 1750 the tempo will increase and the song will play more quickly V Save NotesAndDurations bs2 under the name NotesAndDurationsY ourTurn bs2 y Modify the tempo of NotesAndDurations YourTurn bs2 by adjusting the value of WholeNote Try values of 1500 1750 2000 and 2250 y Re run the program after each modification and decide which one sounds best Entering musical data is much easier when all you have to do is record notes and durations Here are the first eight notes from Beethoven s Fifth Symphony Page 238 What s a Microcontroller Notes DATA IGN UG IGI tem EDAD AB EN Re De Ou Durations DATA 8 8 8 2 8 8 8 8 2 WholeNote CON 2000 y Save your modified program Beethoven sFifth bs2 y Replace the Notes and Durations DATA directives and the WholeNote constant declaration with the code above V Run the program Does it sound familiar Adding Musical Featu
315. ted EXACTLY as shown in Figure 5 8 and Figure 5 9 A Never reverse the supply polarity on the 3300 uF or any other polar capacitor The _ voltage at the capacitors terminal must always be higher than the voltage at its terminal Vss is the lowest voltage 0 V on the Board of Education and BASIC Stamp HomeWork Board By connecting the capacitors negative terminal to Vss you ensure that the polarity across the capacitor s terminals will always be correct Wear safety goggles or safety glasses during this activity Always disconnect power before you build or modify circuits Keep your hands and face away from this capacitor when power is connected y With power disconnected build the circuit as shown starting with a 470 Q resistor in place of the resistor labeled Ri Chapter 5 Measuring Rotation Page 145 Figure 5 8 P7 Schematic for Viewing RC time Voltage Deca 220 Q p R 470 Q g y 3300 UF R R 3 1 kQ Four different resistors Rs 2 kQ will be used as R R 10 kQ shown in the schematic First the schematic will be built and tested with Ri 470 Q then R 1 Mes kQ etc R R R R A Figure 5 9 ae KeS QO Wiring Diagram for X3 i Figure 5 8 P15 Ha p Make sure that the P12 0 ANIUE negative lead of the P11 iall A capacitor is connected P10 P9 on your board the same P
316. th the previous code This is an example of using commas to output a lot of information using only one DEBUG statement Further Investigation In this chapter you visited the Software section of either the Parallax web site or the Parallax CD to get a copy of the BASIC Stamp Editor You can go to the Documentation sections of either the Parallax web site or the Parallax CD to get a free copy of this text and of the BASIC Stamp Manual Printed copies can also be purchased from Parallax BASIC Stamp Manual Users Manual Version 2 0c Parallax Inc 2000 You can learn much more about the DEBUG and END commands by looking them up in the BASIC Stamp Manual You can find them using the Table of Contents The BASIC Stamp Manual has many more examples you can try along with lessons similar to those in the Projects section you just completed Chapter 2 Lights On Lights Off Page 37 Chapter 2 Lights On Lights Off INDICATOR LIGHTS Indicator lights are so common that most people tend not to give them much thought Figure 2 1 shows three indicator lights on a laser printer Depending on which light is on the person using the printer knows if it is running properly or needs attention Here are just a few examples of devices with indicator lights car stereos televisions VCRs disk drives printers and alarm system control panels i gt ee Figure 2 1 oe Indicator Lights Attention Turning an indicator light on and off is
317. the negatively charged molecule to the positively charged molecule Batteries keep a compound with negatively charged molecules separated from a compound with positively charged molecules Each of these compounds is connected to one of the battery s terminals the positively charged compound is connected to the positive terminal and the negative compound is connected to the negative terminal A1 The volt is a measurement of electric pressure and it s abbreviated with a capital V You 1 may already be familiar with the nine volt 9 V battery used to supply power to the Board of eg Education or HomeWork Board Other common batteries include the 12 V batteries found in cars and the 1 5 V AA batteries used in calculators handheld games and other devices What s Current Current is a measure of the number of electrons per second passing through a circuit Sometimes the molecules bond in a chemical reaction that creates a compound that is neutrally charged Other times the electron leaves the negatively charged molecule and joins the positively charged molecule by passing though a circuit like the one you just built and tested The letter most commonly used to refer to current in schematics and books is capital I What s an amp An amp is the basic unit of current and the notation for the amp is the capital A Compared to the circuits you are using with the BASIC Stamp an amp is a very large amount of current It
318. through values SSTAMP BS2 PBASIC 2 5 DEBUG Program Running counter VAR Byte DO LOW 5 FOR counter 0 TO 127 PULSOUT 6 1 PAUSE 10 NEXT HIGH 5 Page 272 What s a Microcontroller FOR CONCE r Q TOT PULSOUT 6 1 PAUSE 10 NEXT LOOP Your Turn Changing the Rate and Condensing the Code You can increase or decrease the rate at which the LED gets brighter and dimmer by changing the PAUSE command s Duration argument Modify and re run the program using PAUSE 20 and note the difference in the rate that the LED gets brighter and dimmer Repeat for PAUSE 5 You can also use a command called TOGGLE to make this program simpler TOGGLE changes the state of a BASIC Stamp I O pin If the I O pin was sending a high signal TOGGLE makes it send a low signal If the I O pin was sending a low signal TOGGLE makes it send a high signal Save DigitalPotUpDown bs2 as DigitalPotUpDownWithToggle bs2 Modify the program so that it looks like the one below Run the program and verify that it functions the same as the DigitalPotUpDown bs2 Compare the number of lines of code it took to do the same job Running out of program memory is a problem many people encounter when their BASIC Stamp projects get large and complicated Using TOGGLE instead of two FOR NEXT loops is just one example of many techniques that can be used to do the same job with half the code What s a Micro
319. tic shows what happens when P15 is set to Vss and P14 is set to Vdd The electrical pressure is now reversed The red LED shuts off and does not allow current through Meanwhile the green LED turns on and current passes through the circuit in the opposite direction 2 Figure 2 20 Current Z rA Manual bi color aie LED Test HIGH Vdd P15 YY LOW Vss P14 Current through Red LED above LOW Vss P15 and Green LED 1 below Z 4 f Current HIGH Vdd P14 470 Q Figure 2 20 also shows the key to programming the BASIC Stamp to make the bi color LED glow two different colors The upper schematic shows how to make the bi color LED red using HIGH 15 and Low 14 The lower schematic shows how to make the bi color LED glow green by using Low 15 and HIGH 14 To turn the LED off send low signals to both P14 and P15 using Low 15 and Low 14 In other words use Low on both pins Chapter 2 Lights On Lights Off Page 65 The bi color LED will also turn off if you send high signals to both P14 and P15 Why e Because the electrical pressure is the same at P14 and P15 regardless of whether you set 1 both W O pins high or low Example Program TestBiColorLED bs2 V Reconnect power V Enter the TestBiColorLed bs2 code into the BASIC Stamp Editor V Run the program y Verify that the LED cycles through the red green and off states What s a Microcontroller TestBiColorLed bs2 Turn bi color LED red th
320. tion save and run your program DEBUG What s 7 X 11 CR The answer is DEC 7 11 Solutions Q1 A microcontroller is a kind of miniature computer found in electronic products Q2 The BASIC Stamp module contains a microcontroller called the PIC16C57 Q3 If the appliance has buttons and a digital display these are good clues that it has a microcontroller inside Q4 A comment Q5 DEBUG and END Q6 Disconnect the power from the BASIC Stamp project E1 It multiplies the two operands 7 and 11 resulting in a product of 77 The asterisk is the multiply operator E2 The Debug Terminal would display 18 E3 To fix the problem add a carriage return the cr control character DEBUG DEC 7 11 DEBUG CR DEC 7 11 P1 Here is a program to display a solution to the math problem 1 2 3 4 SSTAMP BS2 PBASIC 2 5 Chapter 1 Getting Started Page 35 DEBUG What s 1 2 3 4 DEBUG CR The answer is DEBUG DEC 14 2 3 4 END P2 The last three DEBUG lines can be deleted An additional cr is needed after the Hello message What s a Microcontroller FirstProgramYourTurn bs2 BASIC Stamp sends message to Debug Terminal SSTAMP BS2 SPBASIC 2 5 DEBUG Hello it s me your BASIC Stamp CR DEBUG What s 7 X 112 CR The answer is DEC 7 11 END The output from the Debug Terminal is Hello it s me your BASIC Stamp What s 7 X 11 The answer is 77 This output is the same as it was wi
321. tional discount pricing and classroom packs for our Stamps in Class kits and other selected products Technical Support support parallax com Contact our Tech Support Team for general questions regarding the set up and use of any of our hardware or software products TEACHER S GUIDE Each chapter summary contains a set of questions exercises and projects with solutions provided A Teacher s Guide is also available for this text It contains an additional set of solved questions exercises and projects as well as some expanded and alternative solutions to the material in the text The Teacher s Guide is available free in both Word and PDF file formats by joining the Parallax Educators Yahoo Group or by emailing stampsinclass parallax com To obtain these files you must provide proof of your status as an educator THE STAMPS IN CLASS CURRICULUM What s a Microcontroller is the gateway text to our Stamps in Class curriculum After completing this text you can continue your studies with any of the Student Guides listed below All of the books listed are available for free download from www parallax com The versions cited below were current at the time of this printing Please check our web sites www parallax com or www stampsinclass com for the latest revisions we continually strive to improve our educational program Stamps in Class Student Guides For a well rounded introduction to the design practices that go into modern dev
322. trolledLed bs2 works e Do the commands between here and the Loop statement over and over again o Display the value of IN3 in the Debug Terminal o If the value of IN3 is 1 Then Turn the LED on Wait for 1 20 of a second Turn the LED off Wait for 1 20 of a second o Else if the value of IN3 is 0 do nothing but wait for the same amount of time it would have taken to briefly flash the LED 1 10 of a second e Loop Chapter 3 Digital Input Pushbuttons Page 83 Your Turn Faster Slower yV Save the example program under a different name V Modify the program so that the LED flashes twice as fast when you press and hold the pushbutton y Modify the program so that the LED flashes half as fast when you press and hold the pushbutton ACTIVITY 4 TWO PUSHBUTTONS CONTROLLING TWO LED CIRCUITS Let s add a second pushbutton into the project and see how it works To make things a little more interesting let s also add a second LED circuit and use the second pushbutton to control it Pushbutton and LED Circuit Parts 2 Pushbuttons normally open 2 Resistors 10 kQ brown black orange 2 Resistors 470 Q yellow violet brown 2 Resistors 220 Q red red brown 2 LEDs any color Adding a Pushbutton and LED Circuit Figure 3 12 shows a second LED and pushbutton circuit added to the circuit you tested in the previous activity V Build the circuit shown in Figure 3 12 If you need help buildi
323. trols the direction input or output of I O pins P8 through P15 ouTH controls the high or low signals that each I O pin sends As you will soon see ouTH is especially useful because you can use it to set the high low signals at eight different I O pins at once with just one command Here is an example program that shows how these two variables can be used to count from 0 to 9 on the 7 segment LED display without using HIGH and LOW commands Example Program DisplayDigits bs2 This example program will cycle the 7 Segment LED display through the digits 0 through 9 V Enter and run DisplayDigits bs2 Verify that the digits 0 through 9 are displayed What s a Microcontroller DisplayDigits bs2 Display the digits 0 through 9 on a 7 segment LED display SSTAMP BS2 SPBASIC 2 5 DEBUG Program Running OUTH 00000000 OUTH initialized to low Dig Sa Set P8 P15 to all output low iF Whlepltes t BAFG CDE OUTH 11100111 0 PAUSE 1000 OUTH 10000100 le Page 176 What s a Microcontroller PAUSE 1000 OUTH 11010011 PAUSE 1000 OUTH 11010110 PAUSE 1000 OUTH 10110100 PAUSE 1000 OUTH 01110110 PAUSE 1000 OUTH 01110111 PAUSE 1000 OUTH 11000100 PAUSE 1000 OUTH 11110111 PAUSE 1000 OUTH 11110110 PAUSE 1000 DIRH 00000000 END How DisplayDigits bs2 Works I O pins to input Sequents oft Figure 6 12 shows how you can use the DIRH and ouTH variables to control the
324. ually 14000 ms a measurement of 14 seconds This has to be fixed It turns out that executing the loop itself along with adding one to the timeCounter variable takes about 1 ms without the PAUSE 1 command This is called code overhead and it s the amount of time it takes for the BASIC Stamp to execute the commands A quick fix that will improve the accuracy is to simply comment out the PAUSE 1 command by deleting it or adding an apostrophe to the left of it PAUSE 1 y Try commenting PAUSE 1 and test to see how accurate the program is Instead of commenting the delay another way you can fix the program is to multiply your result by two For example just before the DEBUG command that displays the number of ms you can insert a command that multiplies the result by two timeCounter timeCounter 2 lt Add this DEBUG Your time was DEC timeCounter ms CR CR y Uncomment the PAUSE command by deleting the apostrophe and try the multiply by two solution instead Chapter 3 Digital Input Pushbuttons Page 95 For precision you can use the operator to multiply by a value with a fraction to make your answer more precise The operator is not hard to use here s how 1 Place the value or variable you want to multiply by a fractional value before the operator 2 Take the fractional value that you want to use and multiply it by 256 3 Round off to get rid of anything to the right of the decimal point
325. uch current as if you adjusted the potentiometer for maximum brightness When the BASIC Stamp sends a low signal to this circuit it will cause the transistor to stop conducting current and the LED should emit no light Chapter 9 Electronic Building Blocks Page 267 What s the difference between this and connecting an LED circuit to an I O pin BASIC Stamp 1 O pins have limitations on how much current they can deliver Transistors have limitations too but they are much higher In the ndustrial Control Student Guide a transistor is used to drive a small DC fan It is also used to supply large amounts of current ew toa small resistor that is used as a heating element Either of these two applications would draw so much current that they would quickly damage the BASIC Stamp but the transistor takes it in stride Build the circuit shown in Figure 9 4 Write a program that sends high and low signals to P8 twice every second HINT LedOnOff bs2 from Chapter 2 needs only to be modified to send high low signals to P8 instead of P3 Remember to save it under a new name before making the modifications V Run the program and verify that it gives you on off control of the LED lt a e Vdd Figure 9 4 Circuit that Gives BASIC Stamp Transistor On Off Control P8 D 100 kQ
326. udy day INTRODUCING THE PHOTORESISTOR Light sensors have many different functions and they come in different shapes sizes and with different price tags Some sensors are designed to sense a particular color of light such as blue green red or infrared Some sensors don t care what color the light is because they react to how bright the light is Other sensors look for only special kinds of light given off by certain chemical reactions Light sensors also have a variety of ways to tell a microcontroller what they see Some sensors send a voltage some send a sequence of binary values and others react to different kinds of light or light levels by changing resistance Of the light sensors that react to light by changing their resistance the photoresistor shown in Figure 7 1 is probably the most common least expensive and easiest to use Its active ingredient is a chemical compound called cadmium sulfide CdS This compound changes resistance depending on how bright the light is that shines on its collecting surface Bright light causes low resistance values between the two leads while dim light causes higher resistance values Page 190 What s a Microcontroller Figure 7 1 Photoresistor Schematic and Part Drawing The photoresistor s cadmium sulfide coated light collecting surface is shown at the top of the part s drawing As with a potentiometer you can use a photoresistor in an RC time circuit The program to read
327. ug Terminal to set the digital pot s tap By changing the tap setting on the digital pot you change the brightness of the LED connected to the transistor that the digital pot controls Figure 9 9 shows an example of entering the value 120 into the Debug Terminal s Transmit Windowpane while the program is running Since the old tap setting was 65 the LED becomes nearly twice as bright when it is adjusted to 120 Windowpanes Transmit Receive Chapter 9 Electronic Building Blocks Page 275 BEE Com Port Baud Rate Parity COMI asoc z None z Data Bis Flow Conto qx f DTR FATS Figure 9 9 St Ir H em es ecs Sending Messages to the BASIC Stamp Tap setting is 65 Enter new tap Click the Transmit upper Windowpane and enter the numbers for the new tap setting 120 V Enter and run TerminalControlledDigtialPot bs2 Enter values between 0 and 127 into the Debug Terminal Make sure to press the enter key after you type in the digits seece THES Jesccececteeeeeeeneereneeenneerterercersceeeneneereceoneese What s a Microcontroller TerminalControlledDigitalPot bs2 Update digital pot s tap based on Debug Terminal user input SSTAMP BS2 US SPBASIC 2 5 UdPin CON ClkPin CON TROE Constants DelayPulses CON DelayReader CON U eaaa Variables counter VAR oldTapSetting VAR newTapSetting VAR 0 0 oldTapSetting newTapSetting Initialization Byte Byte Byt
328. umoBot is a registered trademark of Parallax Inc HomeWork Board is a trademark of Parallax Inc Boe Bot is a trademark of Parallax Inc or Toddler is a trademark of Parallax Inc respectively upon the first appearance of the trademark name Other brand and product names are trademarks or registered trademarks of their respective holders ISBN 1 928982 02 6 DISCLAIMER OF LIABILITY Parallax Inc is not responsible for special incidental or consequential damages resulting from any breach of warranty or under any legal theory including lost profits downtime goodwill damage to or replacement of equipment or property or any costs of recovering reprogramming or reproducing any data stored in or used with Parallax products Parallax Inc is also not responsible for any personal damage including that to life and health resulting from use of any of our products You take full responsibility for your BASIC Stamp application no matter how life threatening it may be WEB SITE AND DISCUSSION LISTS The Parallax Inc web site www parallax com has many downloads products customer applications and on line ordering for the components used in this text We also maintain several e mail discussion lists for people interested in using Parallax products These lists are accessible from www parallax com via the Support Discussion Groups menu These are the lists that we operate g BASIC Stamps With over 4 000 subscri
329. upply Vin or Vdd for the Parallax i Standard Servo If you are using a 9 V battery it is best to set it to Vdd Either setting will 1 work if you are using a 6 V battery pack Use only Vdd if you are using a DC supply that plugs into an AC outlet Before using a DC supply make sure to check the specifications for acceptable DC supplies listed in Appendix D Batteries and Power Supplies Build the circuit shown in Figure 4 6 Make sure you did not plug the servo in upside down The white red and black wires should line up as shown in the figure a a White gt Red gt Black gt Figure 4 6 Servo and LED Indicator on Board of Education Rev C PARALLAX www parallax com Page 108 What s a Microcontroller Up until now you have been using the 3 position switch in the 1 position Now you will move it to the 2 position to turn on the power to the servo header y Supply power to the servo header by adjusting the 3 position switch as shown in Figure 4 7 Your servo may move a bit when you connect the power Reset Figure 4 7 Power turned on to C E Board of Education o 1 2 and Servo Header _ gt V Move on to Programming Servo Control on page 113 BASIC Stamp HomeWork
330. ure out the highest value not used by your PBASIC program The numbers on the left side of the main Memory Map graph shown in Figure 7 8 on page 198 are hexadecimal numbers and 79A is the highest value not occupied by a program token Hexadecimal means base 16 so 79A is really 7x16 9x16 Ax16 7x16 9x16 10x16 7x256 9x16 10x1 1946 Why does this add up ot 1946 instead of 1947 There are 1947 total addresses free but they are numbered Address 0 through Address 1946 You can also program the BASIC Stamp to make this conversion for you using the DEBUG command s DEC formatter and the hexadecimal operator like this DEBUG DEC 79A For a reminder about hexadecimal numbers see the information box on page 179 Example Program StoreLightMeasurementsInEeprom bs2 This example program demonstrates how to use the WRITE command by taking light measurements every 5 seconds for 2 2 minutes and storing them in EEPROM V Enter and run StoreLightMeasurementsToEeprom bs2 y Record the measurements displayed on the Debug Terminal so that you can verify the measurements read back from the EEPROM Gradually increase the shade over the photoresistor during the 2 2 minute test period for meaningful data What s a Microcontroller StoreLightMeasurementsInEeprom bs2 Chapter 7 Measuring Light Page 201 Write light measurements to EEPROM SSTAMP BS2 SPBASIC 2 5 time VAR Word eep
331. urfaces Dials can also be found in audio equipment where they are used to adjust how music and voices sound Figure 5 1 shows a simple example of a dial with a knob that is turned to adjust the speaker s volume By turning the knob a circuit inside the speaker changes and the volume of the music the speaker plays changes Similar circuits can also be found inside joysticks and even inside the servo used in Chapter 4 Controlling Motion Figure 5 1 Volume Adjustment on a Speaker THE VARIABLE RESISTOR UNDER THE DIAL A POTENTIOMETER The device inside sound system dials joysticks and servos is called a potentiometer often abbreviated as a pot Figure 5 2 shows a picture of some common potentiometers Notice that they all have three pins Page 140 What s a Microcontroller K Figure 5 2 iff A Few Potentiometer mn Examples Figure 5 3 shows the schematic symbol and part drawing of the potentiometer you will use in this chapter Terminals A and B are connected to a 10 kQ resistive element Terminal W is called the wiper terminal and it is connected to a wire that touches the resistive element somewhere between its ends Figure 5 3 Potentiometer 10 kQ Pa Schematic Symbol Pot oe and Part Drawing B Figure 5 4 shows how the wiper on a potentiometer works As you adjust the knob on top of the potentiometer the wiper terminal contacts the resistive element at different places As you turn
332. w signals means you used a BASIC Stamp I O pin as an output In this chapter you will use a BASIC Stamp I O pin as an input As an input an I O pin listens for high low signals instead of sending them You will send these signals to the BASIC Stamp using a pushbutton circuit and you will program the BASIC Stamp to recognize whether the pushbutton is pressed or not pressed Other terms that mean send high low and receive Sending high low signals is described in different ways You may see sending referred to as transmitting controlling or 1 switching Instead of high low you might see it referred to as binary TTL CMOS or Boolean signals Another term for receiving is sensing ACTIVITY 1 TESTING A PUSHBUTTON WITH AN LED CIRCUIT If you can use a pushbutton to send a high or low signal to the BASIC Stamp can you also control an LED with a pushbutton The answer is yes and you will use it to test a pushbutton in this activity Introducing the Pushbutton Figure 3 1 shows the schematic symbol and the part drawing of a normally open pushbutton Two of the pushbutton s pins are connected to each terminal This means that connecting a wire or part lead to pin 1 of the pushbutton is the same as connecting it to pin 4 The same rule applies with pins 2 and 3 The reason the pushbutton doesn t just Page 72 What s a Microcontroller have two pins is because it needs stability If the pushbutton only had two pins those
333. y Activity 1 can be used as a step by step reference for getting the software and Activity 2 can be used as a reference for the installation procedure Page 6 What s a Microcontroller Computer System Requirements You will need either a PC or laptop computer to run the BASIC Stamp Editor software Getting started with BASIC Stamp programming is easiest if your PC or laptop has the following features Microsoft Windows 95 or newer operating system e A serial or USB port e ACD ROM drive World Wide Web access or both USB Port Adapter If your computer only has USB ports you will need a USB to Serial ea Adapter See Appendix A USB to Serial Adapter for details and installation instructions Downloading the Software from the Internet It s easy to download the BASIC Stamp Editor software from the Parallax web site The web page shown in Figure 1 8 may look different from the web page you see when you visit the site Nonetheless the steps for downloading the software should still be similar to these y Using a web browser go to www parallax com shown in Figure 1 8 y Point at the Downloads menu to display the options V Point at the BASIC Stamp Software link and click to select it jax Microsoft Internet Explorer of x File Edt View Favorites Tools Help 9 OF js Address E http 7 wmw parallax com Go PAQ AX 7 BASIC Stamp www parallax com
334. y chances are it also has a programmable microcontroller brain Figure 1 1 wa Every Day Examples of Devices that Contain Microcontrollers Try making a list and counting how many devices with microcontrollers you use in a typical day Here are some examples if your clock radio goes off and you hit the snooze button a few times in the morning the first thing you do in your day is interact with a microcontroller Heating up some food in the microwave oven and making a call on a cell phone also involve operating microcontrollers That s just the beginning Here are a few more examples turning on the television with a handheld remote playing a handheld game using a calculator and checking your digital wristwatch All those devices have microcontrollers inside them that interact with you THE BASIC STAMP 2 YOUR NEW MICROCONTROLLER Parallax Inc s BASIC Stamp 2 module shown in Figure 1 2 has a microcontroller built onto it It s the black chip with lettering on it that reads PIC16C57 The rest of the components on the BASIC Stamp module are also found in consumer appliances you use every day All together they are correctly called an embedded computer system This name is almost always shortened to just embedded system Frequently such modules are commonly just called microcontrollers The activities in this text will guide you through building circuits similar to the ones found in consumer appliances an
335. y a Parallax technician your values will probably be slightly different e All the way clockwise 1 e All the way counterclockwise 691 Chapter 5 Measuring Rotation Page 155 So how can these input values be adjusted so that they map to the values of 500 and 1000 that are needed to control the servo with the puLsouT command The answer is by using multiplication and addition First multiply the input values by something to make the difference between the clockwise minimum and counterclockwise maximum values 500 instead of almost 700 Then add a constant value to the result so that its range is from 500 to 1000 instead of 1 to 500 In electronics these operations are called scaling and offset Here s how the math works for the multiplication scaling time maximum 61x 691x0 724 500 time minimum em 0 724 691 After the values are scaled here is the addition offset step time maximum 500 500 1000 time minimum 0 724 500 500 The operator that was introduced on page 95 is built into PBASIC for scaling by fractional values like 0 724 Here again are the steps for using applied to 0 724 1 Place the value or variable you want to multiply by a fractional value before the operator time time 2 Take the fractional value that you want to use and multiply it by 256 new fractional value 0 724 x 256 185 344 3 Round off to get rid of anything to the right of the decimal point
336. y be smaller You can click and drag the separator between the two panes downward to make the Transmit Windowpane larger You can type characters into the Transmit Windowpane to send them to the BASIC Stamp In this example somebody typed in 100 then hit the carriage return then typed in 850 The Receive Windowpane displays the Enter number of pulses message sent by the BASIC Stamp It also displays an echo of the characters 100 that were typed into the Transmit Windowpane Chapter 4 Controlling Motion Page 121 Data Bits Flow Control TX DTR T RTS d fo z er ens ecs Figure 4 19 Debug Terminal s Windowpanes lt Transmit Windowpane lt Receive Windowpane Echo is when you send a message and a copy of that message appears in your Receive Windowpane You can click the Echo Off checkbox shown below to make a checkmark appear in it This will make the Debug Terminal stop displaying these echoes l Close I Echo Off as Enter ServoControl WithDebug bs2 into the BASIC Stamp Editor and run it If the Transmit Windowpane is too small resize it using your mouse to click hold and drag the separator downward The separator is shown just above the text message Enter number of pulses in Figure 4 19 Click the upper Transmit Windowpane to place your cursor there for typing messages When the Debug Terminal prompts you to Enter number of pulses type the number 100 then press
337. y changing both the Duration arguments to 250 it will cause the LED to flash on and off twice per second The DO LOOP in your program will now look like this DO HIGH 14 PAUSE 250 LOW 14 PAUSE 250 LOOP V Open LedOnOff bs2 y Change the PAUSE command s Duration arguments from 500 to 250 and re run the program If you want to make the LED blink on and off once every three seconds with the low time twice as long as the high time you can program the PAUSE command after the HIGH 14 command so that it takes one second using PAUSE 1000 The PAUSE command after the Low 14 command will have to be PAUSE 2000 DO HIGH 14 PAUSE 1000 LOW 14 PAUSE 2000 LOOP y Modify and re run the program using the code snippet above A fun experiment is to see how short you can make the pauses and still see that the LED is flashing When the LED is flashing very fast but it looks like it s just on it s called Page 52 What s a Microcontroller persistence of vision Here is how to test to see what your persistence of vision threshold is Try modifying both of your PAUSE command s Duration arguments so that they are 100 Re run your program and check for flicker Reduce both Duration arguments by 5 and try again Keep reducing the Duration arguments until the LED appears to be on all the time with no flicker It will be dimmer than normal but it should not appear to flicker lt cee lt lt One last thing to try is to cre
338. zer and w piezo is pronounced pE A zO ACTIVITY 1 BUILDING AND TESTING THE SPEAKER In this activity you will build and test the piezoelectric speaker circuit Speaker Parts 1 Piezoelectric speaker 2 Jumper wires Building the Piezoelectric Speaker Circuit The negative terminal of the piezoelectric speaker should be connected to Vss and the positive terminal should be connected to an I O pin The BASIC Stamp will then be programmed to send high low signals to the piezoelectric speaker s positive terminal Build the circuit shown in Figure 8 2 Vdd Vin Vss Figure 8 2 oto oo Piezoelectric Speaker Circuit Schematic and Wiring Diagram X2 How the Piezoelectric Speaker Circuit Works When a guitar string vibrates it causes changes in air pressure These changes in air pressure are what your ear detects as a tone The faster the changes in air pressure the higher the pitch and the slower the changes in air pressure the lower the pitch The element inside the piezo speaker s plastic case is called a piezoelectric element When high low signals are applied to the speaker s positive terminal the piezoelectric element Chapter 8 Frequency and Sound Page 221 vibrates and it causes chan
339. zing Inventions with BASIC Stamp Microcontrollers ccceseeeeeeeeeeeeeeeeees 2 Hardware and Software ccccccceceecesceeeeeceeeeeeaeeeeecaeeeeecaeeeeeeaeeeeesaeeessseeeeseseeeseeaees 5 Activity 1 Getting the Software ccccccccceseecceeeeeceeeeeeeeeeeeeaeeeeeecaeeeeeeeaeeeeeeneeetesaees 5 Activity 2 Installing the Software ccccccceceecceeeeeeceeeeeeeceeeeeneeeeeeeeeeeeeneeeeeseeeeetees 10 Activity 3 Setting Up the Hardware and Testing the System scceeeeeeeeeees 13 Activity 4 First Program ccccccccescsceceeeeeeeeeeeneeeeeeeceeeeecaeeeesecaeeeeesneeeeecneeeeeenneeeeeees 20 Activity 5 Looking Up Answers ccccsccceeeeeeeeeeeeeeeeeeeeeeeeeeeaeeeeeeaneeeeeseeeetenneeeetees 27 Activity 6 Introducing ASCII Code cceceeceeeeeeeceeeeeeeceeeeeeeeeeeseeeeeeeeseeeeeseneeeesees 30 Activity 7 When You re Dome cccceeccceeeeeeeeeeeeeceeeeeeeeeeeecaeeeeecaeeeeeseeeeeeeeeeetees 31 SUMIMANY ice fhe fast ikea E Ae EE AAS A RA cee PA eA 33 Chapter 2 Lights On Lights Off ccccsccsseeeeseeeeeeeeeseeeseseeeenseeeeeseeesneeeenseeeeeeees 37 Indicator Lights aaier atapa aai e paii deen i a atasi ai 37 Making a Light Emitting Diode LED Emit Light 0 ccccecccseeeeeeeeeeeeeeeeeeeeeeeeeeees 37 Activity 1 Building and Testing the LED Circuit cccccccecceceeeeeeeeeeeeeeeeeeeeeeeetees 38 Activity 2 On

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