Learning to code - with a purpose Part 1 Adrian
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1. Blink void setup pinMode 13 OUTPUT void loop digitalWrite 13 HIGH delay 1000 digitalWJrite 13 LOW delay 1000 LilyPad Arduino USB on COM10 9V battery so that you can power the board independently and unplug the USB cable So you are now set up for autonomous sense and control A very recent addition to the resources to help would be gadgeteers is a free gift from Autodesk called Project Ignite suggest you leave your Arduino in the box for another 15 minutes or so and run the introductory lesson at https projectignite autodesk com app project 9 lesson 43 overview Below is my completed attempt at the Arduino Introduction unit You can do everything you would normally do with a physical Arduino breadboard and components in wiring up your own circuits You can also develop the Arduino code to control it and then simulate the result Clicking on Components brings up a tray full of device from which you can select some LEDs and resistors to drag onto the breadboard 47 edit breadboard C fi 5 Apps I Adrian E Google Yahoo Mail BT Yahoo Mail KA Bognor Met Office AccuWeather Barnh A 123d circuits io circuits 515647 123D Circuits Circuits Arduino Introduction Cc O E K Finishing up E You have just made your first Arduino circuit Congratulations s Now it s time to adapt this circuit as you want for example extend your LED strip with2. download the free IDE software integrated development environment from the Arduino site http arduino cc en Main Software The common starting point is usually to write a program which turns a LED on and off continuously An example is at http arduino cc en Tutorial Blink Here is the sample code with all the comments stripped out Once installed in the Arduino it will run the loop continuously until the reset button is pushed Here is the code entered into the Arduino IDE The left hand green icon shown as a _ tick mark is used to compile the program into a binary file called a sketch If there are syntax errors in the code they will be detected and shown in red in the bottom window Our program is correct and so has compiled correctly You can now connect an Arduino to the computer and use the tools menu to select the right kind of board and select which USB port to use Then you use the second green icon the right arrow to download your binary file to the Arduino If you run the program with the USB cable and the right LED and 220 ohm resistor wired up correctly then the program will run and the LED will blink away merrily The kit also contains a battery connector which clips onto a int led 13 void setup pinMode led OUTPUT void loop digitalWrite led HIGH delay 1000 digitalWrite led LOW delay 1000 Blink Arduino 1 0 6 _ i File Edit Sketch Tools Help
3. next step is to open the black battery box and install 3 AA batteries Notice there is a small on off switch on the box This will provide the power needed to switch outputs like LEDs and motors It will also allow you to run the stored program on Crumble when you disconnect it from the computer Connect it to the Power In and contacts on the top left of the board Now start the program again and the LED should flash very brightly While the LED is flashing carefully pull out the USB connection to the Crumble The program should continue running so you have now created an autonomous device Save the program The starter kit gives you two LEDs two motors a Sparkle LED board and a buzzer as outputs It also provides a micro switch and a light dependent resistor as inputs Now we have enough power on the board to drive the outputs we can test each of them Open the Blinky program again Disconnect the external LED Use a black lead to connect the ve output for Motor 1 to one of the tiny connectors on one of the motors and a red lead to connect the other to the ve output on Crumble Now when you run the program you should see and hear the motor starting running and stopping Switch the ON OFF button on the battery box to OFF you should see the on board LED continue to flash but the motor will no longer work Exercise 6 2 Add commands to make Motor 1 run forward stop run back and stop repeatedly Now we will use the Sparkle u
4. we could extend the idea to sense and control some physical gadgets like switches and lamps One popular input device is called MaKey MaKey which costs around 50 e g from UJ al 2 oO E st 4 T 3 3 2 2 Maplin http www maplin co uk p makey makey invention kit n71nr It iS ENNO supported by an extensive website of resources projects eol oo oo OO 00 OO guides and blogs One fun example is how it can be used as a games controller such as for carrying out surgical procedures on Scratch the cat http makeymakey com guides For a simple test connect the board with a USB cable Use one of the crocodile clip connector cables supplied to connect your left hand to one of the EARTH connectors Then touching the SPACE disk on the front of the board lights a green LED and will be detected by Scratch as pressing the Space Bar Test it with this little program ke space ressed en SScratch Made O er tion key sp pressed th p ame i f ka g i Mre P d f y E i A An Operation type board game that uses the MaKey MaKey to interface with a computer running Scratch Project Details Another answer is to buy the simple control board called the Picoboard which costs around 30 e g from Maplin http www maplin co uk p picoboard for scratch n79dp Mini USB ER The board contains a slider linear potentiometer light sensor audio sensor giii 3 i four crocodile clip resistance sensors and a pushbutton It conne
5. Jar 3 514 KB a Homegroup B Adrian vr ardublock all State 2B Shared Size 3 43 MB Shared with Homegroup Executable Jar File Date modified 05 01 2015 18 26 Date created 05 01 2015 18 27 Once you have created the tools ArduBlockTool and tool directories you can copy and paste the downloaded file and rename it to ardublock all jar When you open the Arduino IDE and select the Tools menu you should see that Ardublock now appears about half way down Clicking on this opens up the Ardublock editor ees 1 stent rin 106 tt save load Upload File Edit Sketch Tools Help _ Auto Format Ctrl T Archive Sketch Fix Encoding amp Reload Serial Monitor Ctrl Shift M Control Pins i sketch_jan05 Number CGonstants Operators ArduBlock Utilities ae DERobot Serial Port Seeedstudio Grove Programmer iinkermHKit Burn Bootloader See what the various menus on the left contain Use the Control menu to pick up the do loop Use the Pins menu to pick up the set digital pin block Edit the pin number to 13 Use the Utilities menu to pick up the delay milliseconds block Repeat these again Open the Number Constants menu From the second set digital pin block drag the red HIGH into the menu and replace it with the red LOW block Z ArduBlock Task2 abp b le sketch jan05a Arduino 1 06 Control Pins digitalipin
6. Learning to code with a purpose Part 1 Adrian Oldknow Jan 2015 adrian ccite org 1 Introduction The Turing anniversary and the release of The Imitation Game film have helped to bring attention to the UKs pivotal role in the development of electronic computers The success of the Raspberry Pi last week s Royal Institution s Christmas Lectures Sparks Will Fly and the increasing public awareness and interest in the Internet of Things loT look like stimulating the same sort of public enthusiasm for home computing which the BBC micro achieved in the 1980s The key difference is that the raw materials for assembling intelligent devices at home are now staggeringly cheaper smaller and reliable than their counterparts 30 years ago Part of the popular appeal of the BBC micro was that you could achieve a lot with relatively simple programs written in a dialect of the Basic programming language As well as outputting coloured text and graphics on the screen you could make music and noises with the on board speakers It also had a user port which could be connected both to receive inputs from sensing devices and to send outputs to control lights motors and other electro mechanical devices Home robotics is not new but it is now much more accessible This is also made much more possible through the Internet e mail and mobile communications where you can instantly download the software driver video user manual help sheets
7. al http www raspberrypi org cas educational manual This includes chapters written by Graham Hastings of St John s College School in Cambridge on using Scratch I also made a contribution on the free maths and science software called GeoGebra You don t need a Raspberry Pi to use these resources In order to make a Scratch program respond to an event we need to be repeat until key a pressed able to include some form of sensing The simplest way is like with 3 many video games to respond to the keyboard sensing whether a particular key is being pressed The Scratch program shows the basic an idea The program will continue to run until the a key is pressed It Pay degrees continually monitors the keyboard to see if the space bar is being l pressed When it is then the Scratch icon spins right a little and when it is not then it spins left Just click on the first statement to set Scratch spinning and see how it responds to the keyboard if key Space Hossein then pies a 5 degrees Can you alter the program so that Scratch turns left when the left arrow is pressed turns right when the right arrow is pressed moves forward when the up arrow is pressed moves back when the down arrow is pressed and stays still when no key is being pressed How can you make the program stop 3 MaKey MaKey and PicoBoard So we have now used Scratch to control a simple on screen sense and response program It would be more fun if
8. and other resources often free to get you going without delay Whether or not you are interested in learning to control devices by writing your own programs you are probably far more proficient than me anyway you might have family members currently involved in education 5 18 who are interested Electronics appears in the Physics syllabus coding appears in the Computing syllabus and control systems appear in the Design Technology DT syllabus As a STEM Ambassador at the Winchester Science Centre am involved in working with fellow Ambassadors from industry in helping teachers deliver aspects of these subjects which are currently relatively unfamiliar to them Within the current Computing curriculum most students will encounter Scratch and Python as the most commonly taught programing languages Let s start with Scratch 2 Scratch In the early days of electronic computing so called high level programming languages were developed for different applications COBOL was developed for commercial applications Fortran and Algol for scientific ones and LISP for natural language ones As part of the Man And Computer MAC project at MIT Seymour Papert and Marvin Minsky developed a graphical programming system for a floor turtle a wheeled robot device with a pen which can be moved up and down which was connected to the computer by a cable Its turtle graphics commands included instruction like Forward 5 Right 90 and Pe
9. around 60 http www amazon co uk Lego Education WeDo Resource Set dp Boo6zkvapc The main component of this kit is a small block which connects to the USB port of a computer and to which you can connect a motor and either or both of two sensors Information about the l po Pe sensors is at http www legoengineering com wedo sensors The IR motion sensor can a Pa detect objects very roughly up to 15 cm away depending on the shape of the ale object and other properties reflection colour etc The tilt sensor detects changes in position It can detect six different positions tilt this way tilt that way tilt up tilt down no tilt and any tilt LEGO has its own graphical software for sensing and control with WeDo but it is very expensive c 50 and WeDo works fine with Scratch which is free http www rapidonline com design technology lego education wedo software plus activity pack 300536 To test the kit we can build a small buggy powered by the motor which responds to the motion sensor by moving forward until it detects an object in its path and then reversing back and stopping Better still we can combine it with the light sensor on the Picoboard to simulate a Mars explorer vehicle You will need to build a simple three wheeled buggy from Technical Lego with the motor engaging a gear to rotate the rear axle The chassis supports the LEGO USB brick which connects to the motor and to the motion sensor which sticks out in front o
10. awler program for Robotiky Now we are getting much closer to the heart of the sense and respond mechanism a sophisticated programmable chip called a microcontroller One of the commonest of these currently in use is the cheap Arduino system robo ledColor red y start program robo ledColor green for var i3 0 i3 lt 4 134 robo moveForward 1 robo turnRight 90 _m start program LED color green while robo pathAheadClear move forward LED color red turn night tum right move forward move forward LED color blue developed by Italian engineers But before tackling Arduino we will next meet a very new kid on the block the Crumble microcontroller 6 Crumble and Sparkle The Crumble microcontroller is a recent educational project from Redfern Electronics in Cambridgeshire developed by Joseph Birks http redfernelectronics co uk crumble It can be purchased through Middlesex University s Mindsets Online at 10 VAT pp or as a starter kit for 20 VAT pp 29 94 This kit contains 1 x Crumble controller 8 x Crocodile Clip leads 2 x Ultra bright LEDs 1 x USB to Micro USB lead 1 x Sparkle 1 x Light Dependent Resistor 1 x D C Buzzer Instructions amp Project Suggestions Micro USB i Gas D oe at Power Out YY Bai i t InpuvOutput A 1O aid gt input Output O Input Output B Oji i t v9 Input Output C Mo
11. cts to your computer via USB and has a standard micro USB connection on the board sider am sure that more tech confident people than me could design and build T their own cheaper version PicoBoard SNe In order to use this with the Scratch 2 software you need to enable some extra commands Click on More Blocks and then click on Add an Extension when slider gt This will take you into the Extension Library which Inputs for O A B c D F resistance D measurements AANE d dah currently offers you a choice of Picoboard and or LEGO WeDo Select Picoboard and see how this adds some new commands to Scratch as above The sample program uses the slider on the Picoboard to move Scratch forward and backwards The slider aka rheostat returns a value between 0 and 100 The fourth command in the shape of a long oval returns a number which we can use in a test green statement to control an If loop There are several other sensors on the board which return a value which can be used to control an action repeat until key space pressed slider ae Slider light sound if slider sensor value lt Eq then movre steps eke f 7 resistance A movre steps ae resistance B resistance C resistance D 4 LEGO WeDo The other set of devices which Scratch currently supports for sense and control are made by LEGO They produce the LEGO WeDo resource set which can be bought for
12. d data You could use the Light Dependent Resistor to control when the buggy starts moving by putting a black cloth over it to send it to sleep and only start moving when it senses enough light like the Sun dawning over Mars You could wire up the micro switch as a touch sensor so that it backs off if it hits something in its path You will probably want to try some other sensors of your own or wait for Redfern to design some more So now we have seen a splendid new development from UK engineers to help education At this point we will pick up the thread of the Italian Arduino development board but also see how a Blocks based editor can make it much more user friendly program start frig 5 0 Poe motor 1 at Yg motor 2 at Yg wait seconds A 1 2 STOP motor 2 wait seconds motor 1 at Yg motor 2 at y wait seconds A 1 E STOP motor wait seconds Tem 1 at y Tim 2 at y wait seconds nim 1 E STOP nim 2 E STOP 7 Arduino and Engduino You will need some electronic components such as resistors switches and LEDs If you don t already have a set of your own then a very good starting point is to get the Arduino Starter Kit from Maplin Rapid Amazon etc for around 60 http arduino cc en Main ArduinoStarterkit This includes the basic Arduino UNO board a breadboard for wiring components without soldering a project book and lots of lovely bits and pieces You will also need to
13. f it like a pair of eyes It also carries the Picoboard As the LEGO brick and the Picoboard both need to be connected to USB ports we won t be able to send the vehicle on a very long voyage Now use the Scratch More Blocks and Add an Extension commands to bring in the LEGO WeDo controls to add to the existing Picoboard controls The Scratch program waits until the Sun rises over Mars shine a torch at the light sensor on the Picoboard Then the motor starts moving the vehicle slowly forward until an object is detected in its path Then the vehicle stops makes a noise and beats a stately retreat It would be nice if we could flash a light or two but you will have to make do with making something happen on the Scratch screen instead LEGO WeDo set motor Power to amp turn motor on turn motor o repeat until distance lt 95 set motor power to set motor direction to this wa turn motor off set volume to LOO 0 play note 607 for ea beats set motor direction te reverse when distance lt turn motor on for 1 Secs distance set motor direction to reverse So far we have just been exploring the official Scratch approach But needless to say there are many ingenious people who have hacked their way to use Scratch to interface with other devices such as the Kinect bar developed by Microsoft as a games controller http scratch saorog com An example of this being used to control a pai
14. gduino board developed at University College London UCL http www engduino org This comes with a rechargeable battery and a micro SD card as well as shed loads of LEDs It can be programmed in the Arduino IDE and presumably with ArduBlocks too Once the code has been debugged and uploaded to the Engduino it can be detached and used autonomously It Cees JAU NO Protected Li Po Battery comes with a wide range of on board ra a ae ila C EX sensors which can collect data and store them on the SD card 8 R sum The word coding is often misused Whether you write your programs in Scratch Crumble Robotiky Arduino IDE Ardublock Javascript C or Python really doesn t matter The key skill is designing the program logic aka algorithm to solve the problem you have posed In all but the simplest cases this is likely to be an iterative process of trial and improvement Tackling physical challenges involving sense and response is very powerful way to develop your programming skills as well as helping you to understand the way in which so many of the devices we take for granted nowadays actually work hope this has provided enough but not too much information to get you started on what is sometimes called physical computing hope we can develop a community of practice between school teachers students parents families current engineers experts and other interested parties to exchange info
15. l sketch jan05a Number Constants LEEA S pinMode 13 OUTPUT analogi pini n n ArduBlock Operators _ Winters void lo Ae CECA E op JE EED m PEE E N DERobot m delay 1000 ane Seeedstudio Grove Sie I jb Sages fais P BON MnkenkKit eo GEIS i echomt ultrasonics X If you click on the Upload button your blocks will be turned into Arduino IDE code compiled and if successful uploaded to the Arduino board which you have specified in Tools So this provides a very useful utility to program Arduino in a similar way to the Scratch Robotiky and Crumble approaches we have just seen There is now a fantastic array of sophisticated devices you can buy to enhance your autonomous Arduino projects have recently purchased some incredibly cheap such components from Amazon posted from China have yet to put them into action but here are a a distance measurer such as used by Lego WeDo and Robotiky http www amazon co uk HC SRO4 Distance Measuring Transducer Ultrasonic dp BOO6CHFLR2 LilyPad Arduino USB on COMS b an accelerometer and gyroscope http www amazon co uk MPU 6050 Gyroscope Accelerometer Module Arduino dp BOOCOD97LY and c send and receive transmitters for Arduinos to communicate with each other http www amazon co uk 433Mhz transmitter receiver Arduino project dp BOOE9OGFLQ A variation on the Arduino board is provided by the En
16. m to start program robotiky for l e w Aaii o Run program on simulator move forward 1 move forward g turn right s Vv View code turn right x 1 Start with end program i EA simple blocks robo moveForward 1 end program robo rotateClockwiselgo 2 Create robo moveForward 1 your OWN A key difference between Robotiky and the systems we have met so far is the way it can be programmed from a computer using a USB connector but then disconnected to run autonomously without a trailing umbilical cord This means it has its own battery pack providing power to the unit for the mBed board the LEDs and the motors The system is still under development but as an investor am currently testing the system Currently the programming has to be done online in a web browser once you are registered https www robotiky com code a Drag boxes from the Toolbox into the editor pL Fien Once you have ae developed your code LED color eee 4 you can test it using the powan on screen simulator Open simulator l Write Robotiky code run it move forward turn right on the simulator and robot turn right 3 Create your own custom caer ten mazes by clicking on the turn left grid Press the Green arrow to run the simulator for loop Click on the right most of the four icons in the middle of the red bar at the top to download the compiled binary file to My Downloads Connect the USB cable to the Robotiky unit Use My C
17. more LEDs add an additional switch have the switch control the direction that the LEDs blink etc 1 Arduino uno w Upload amp Run 4 Pin 13 has an LED connected on most Arduino boards give it a name int ledRed 13 int ledGreen 12 int ledBlue 11 int delayTime 500 int switchPin 9 int switchState LOW Perhaps you have noticed that the effect of a switch toggle is only applied when the running light starts over again on the red LED Try to figure out why this happens How would you solve this problem the setup routine runs once when you press reset void setup initialize the digital pin as an output pinMode ledRed OUTPUT pinMode ledGreen OUTPUT pinMode ledBlue OUTPUT pinMode switchPin INPUT 23 23 re ideossssss es DTH m en Pe ELLERS ee ee ES EE Barclays T TheTimes SystmOnlineLogin amp Cr dit Agricole Cent Viglen Work Home 0 Pic s 2 CQ Code Editor Components Start Simulation p gt s s s osooso Libraries Download Code Serial Monitor ZD Click on each resistor to bring up a dialog box to set the resistance to 220 ohms Click on each LED to set its colour Click anywhere on the breadboard to create a wire and click somewhere else to connect it to Click on the wire to change its colour Click and press the Del key if you want to remove a wire or component Click on the Code editor to wri
18. n Up They developed a programming language called Logo which added a range of commands to the existing LISP language As cheaper graphical display devices became available the floor turtle was replaced by a screen simulation usually a simple arrow head Scratch was an updated development from MIT about 10 years ago http scratch mit edu about Developers at Berkeley redesigned the Scratch system around a new interface called Build Your Own Blocks BYOB which is now incorporated into the current Scratch release http scratch mit edu Try playing the short video there to get a feel for the way the system works Along with many current developments the current release version is intended to be run web based but you can download an offline version at http scratch mit edu scratch2download Here is a program assembled from blocks in the graphical editor Just click on the first command to run the program Save it as Hex Here is what Scratch produced go to x My Try editing the turn command to 45 degrees What do you need to do to complete an octagon Now you are a qualified de bugger There are many resources to support Scratch The _ Computing At School CAS group website has many SS which are relevant to the English school Computing curriculum You don t have to be a teacher to subscribe to this site which is free a turn 4 60 degrees A group from CAS wrote the Raspberry Pi Education Manu
19. nit with its multi coloured LED Disconnect any leads attached to the Crumble except the USB and the Battery and leads On the Sparkle find the hole marked with D and an arrow pointing away Connect this to the D port on the Crumble Connect the hole on its left on the Sparkle with a black lead to the ve power out on the Crumble Connect the last hole on the Sparkle with a red lead to the ve power out on the Crumble Use the Blinky program again but this time use set sparkle O to and select the colour red from the palette to replace motor 1 FORWARD at 100 Then use set sparkle to and select the colour black from the palette to replace motor 1 STOP When you run the program the Sparkle s LED will switch to red then off repeatedly Save the program With additional Sparkle units you can wire them in a chain using three leads at atime The next Sparkle unit will be unit 1 the next unit 2 and so on Exercise 6 3 Make Sparkle flash alternatively red then yellow and then green repeatedly To test the buzzer connect its black lead to either of the ve power outputs at the top of the Crumble Connect its red lead to one of the lettered outputs such as C The program to switch the buzzer on and off is exactly the same as the Blinky program but with the Motor commands replaced with Set C HI and Set C LO When you run the program you may have to put your ear very close to the buzzer to hear that is indeed swi
20. omputer to find the drive to which Robotiky will store programs mine is E while 76 Open Simulator CE Drag the bin file from Downloads to Robotiky and the white light will come on and go off When the transfer is complete disconnect the USB cable from the unit so that it is now autonomous When you press the on switch at the back of Robotiky you will see it perform a quick square dance The developers intend Robotiky to be an easy system to use to learn how to move from writing blocks into first generating JavaScript code and then directly to using C look forward to exploring this route The third of the icons in the red bar like an eye turns a block code program into the underlying JavaScript One of the boxes on the menu is an edit block robo moveForward 1 which brings up a blank box As you start to type a robo turnRight 90 command it offers a menu of commands matching robo turnLeft 90 your initial letter So if you type r you can select robo moveForward 1 from the menu to save typing the whole command Then you can edit the argument 1 to e g 4 to make a block which moves Robotiky forward 4 units Similarly you are able see how Robotiky reads sensors such as the distance measurer by using an if block and starting to enter an r into the space after the if This way we stumble across If robo pathAheadBlocked and so we can now re write the basic Mars cr
21. program so that the LED only shines when the Resistor is in the dark Exercise 6 5 Wire up Crumble and write a program to use the Switch attached to the input port C to switch an external LED attached to output port B on and off so that you can the Switch as a Morse Code key Review The Crumble can be programmed using the free Redfern blocks software on a computer Once a program has been written it can transferred to Crumble using the USB connector Every program starts with a red program start block Most programs will run inside a brown loop forever block A program can be interrupted from the computer using the red square button The program can be restarted from the computer using the green triangle button Programs can be saved to and opened from a computer Once a program has been tested and debugged the Crumble can be detached from the computer and powered solely from the 4 5V battery pack The program stored in the free standing Crumble can be stopped and started using the ON and OFF switch on the battery box will finish this short introductory guide by showing how to make another primitive Mars crawler vehicle have a choice of LEGO K Nex and Meccano construction kits but could also use tools to make a chassis out of wood plastic or card Here is my ramshackle vehicle using LEGO to enclose the two motors from the Crumble kit Below there is a close up of how the Crumble has been wired up The battery pack is connec
22. r of LEGO motors on a robot buggy is at https www youtube com watch v 77sH807ig and instructions can be found at http scratched gse harvard edu discussions how do i controlling 2 lego wedomotors gestures kinect So here is a challenge for the techies amongst us Can you give us cheap and cheerful ways of building our own Scratch controlled systems using simple components and or existing devices such as Kinect and or Nintendo s Wii Remote Plus Some ideas are at http wiiphysics site88 net and http ccite org CDK 20 20the 20Cambridge 20Dynamics 20Kit pdf Now that we have explored the Scratch approach to programming with blocks we can find out more about how the Blocks style of programming has been used for other robot and gadgetting systems 5 Robotiky The first of these we will look at is the Robotiky system devised by two recent Cambridge engineering graduates John and Matt http www robotiky com This was crowd sourced through Kickstarter https www kickstarter com projects robotiky robotiky make coding into childs play You can get a free feel for the programming system from the on line sample menu at http www robotiky com There is a step by step introduction which guides you through using an on screen simulation in the form of a grid with blocks forming a maze The physical unit is based on an ARM mBed microprocessor board https mbed org A level selector Return to level obolis E Screen Toolbox Send progra
23. rmation and experiences as well as to help inspire the future generation of technologists the UK needs hope to follow this introduction up with a sequel containing similar information about other interesting developments Please give feedback on this venture All contribution towards taking it forward will be very gladly received Thanks adrian ccite org 14 January 2015
24. tching its buzzing on and off program start So we have now tested all the output units in the starter pack on board LED external LED Motor Sparkle and Buzzer Finally we just need to find out how to make the input devices work First we ll use the micro switch This has three legs marked COM NO loop forever EC E AG motor at end if and NC Connect the black lead from the ve power output to the nna c YOR LO Pee COM leg Connect the red lead from the C output to the leg pr marked NC To sense the switch we use two IF statements The Em hole between the if and then words is for you to insert a test next condition such as Cis HI or Cis LO We will use the motor commands just to switch on and off an on board LED Send and run the program The LED should show red until you close the switch when it goes off See what difference it makes if you move the red lead from the NC leg to the NO leg Note in most versions of Scratch you can use and If Then Else structure rather than the two If s we have used here Finally we can now test the Light Dependent Resistor Connect one of its legs to the ve power output and the other to an output such as C We can use exactly the same program as above to test it When you send and run it the on board LED should show red but if you hold the resistor in your hand to cut off all the light then the LED should go out Exercise 6 4 Modify the
25. te your code as if using the Arduino IDE Click on Start simulation to run your code on the simulated Arduino circuit Once its working OK you can attach a real Arduino to the USB port and click on Download Code to send it to the physical device This really is a fabulous tool for learning how to build and test circuits and code to control them Another very helpful utility is called ArduBlocks and allows us to develop programs for Arduino in a Blocks environment like Scratch before converting them into Arduino IDE code automatically To install the utility you need to download the files from http blog ardublock com engetting started ardublockzhardublock Don t be put off by all the adverts at the Sourceforge site Just wait until the current version downloads something like Ardublock all 20130712 jar This will be in your My Downloads folder You will need to create some new folders in the Arduino directory which has been in installed in My Documents The screen shot below shows which you will need to create Make sure that the Arduino IDE has been closed COU Libraries Documents Arduino tools ArduBlockTool tool v gt il Search tool Organize Open v Share with E mail Burn New folder v Tl Documents library Documents tool a Music r Name Date modified Type Size Arrange by Folder f Pictures E Videos ardublock all 05 01 201518 26 Executable
26. ted to the ve and ve Power input ports The left and right motors are connected to the Motor 1 and Motor 2 ports You will need to experiment with the way to connect the red and black leads for each motor so that when both motors are set to Forward they do both move the buggy forward In order to change direction we need to spin the motors in opposite directions Again you will need to work out which directions to use for a right or aleft turn The only control we shall use is the Wait command to determine how long to go forward to turn and to go backwards You will need to do some measurements to find what distance the buggy will travel forward or backwards in 1 second Also to find what angle it will turn in 1 second when the motors are applied in opposite directions Here is a very simple linear test program It starts with a Wait command to give you time 5 seconds to switch the battery ON and position the vehicle on a hard flat surface preferably a floor Then both motors should work together to drive the buggy forward for 1 second Then the buggy stops for 1 second Next the motors turn in different directions for 1 second Then there is another 1 second pause before both motors drive the buggy backwards for 1 second before stopping which is also the end of the program Exercise 6 6 Can you make the buggy move in a square of side 1m Of course it would be nice if the buggy could move in response to some sense
27. tor 1 hci uk in Fo oot Dies Motor 2 LEO Power in 4 5 to 5 5V f pa o ehelelele g Ww Motor 1 LED 2 x Gearboxes 1 x Microswitch 1 x Switched Battery Box The software is a free download It is a graphical sa environment very similar to Scratch The program gt E o illustrated can be sent to Crumble via the USB cable j program start use Program and select Program Crumble and Run to transfer it Use the green triangle and red square buttons to pe a stop the program Save the rogram as Blinky ee ee For this example you do not need to attach any Inputs Outputs or Power to the Crumble board It will just flash its red LED for Motor 1 on and off Exercise 6 1 Add commands for Motor 2 to blink both the on board LEDs Now we will use one of the LEDs supplied with kit as an external output Connect a red lead to the ve Power Out at the top right of the Crumble controller and to the longer leg of the LED Connect a black lead from its shorter leg to the Input Output connector marked A on the left side of the Crumble Replace the two motor commands in the program with set A HI boxes and change the HI in the second one to LOW When you run the program you will have to look hard at the LED as it is not very bright The power provided to the board via the USB connector is very low and not sufficient to power most of the external outputs So the
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