Design Document
Contents
1. Changing the system from US units to Metric units is done through the touch screen This setting adjusts the proportionality constants for reporting speed temperature and distance data to the driver and also selects different display strings 15 12 11 10 Figure 11 Arduino Uno rev 9 onwntnna amp E t A y 3 microcontroller Figure 12 ezLCD 313 display unit Batt Voltage level Battery System 36 V Mode Select Detect reverse Figure 13 User Interface Block Diagram 16 Figure 15 Arduino interface board atop the Arduino E EI Figure 16 Schematic diagram for interface and sensor boards Testing During preliminary investigations it was found that the signal on the hall effect sensor is 5V pulse train which will require no amplification in order to work with the Arduino s system However this also means that the signal must be read as an interrupt and counted rather than monitored through ADC Originally the signal from the speed sensor was run through the ADC for detection The signal input for the speed sensor was rerouted through a jumper wire to data pin 2 on the Arduino which is one of the two reserved pins for interrupts In order to test the subsystems some of the wiring was simulated on a breadboard The component plugs on the small device sub boards were2. MM74HC132M SJ 3523 SMT TR FST3126MX OSTTCO70162 282836 2 OSTTCO20162 8412 R4 40X3 8 2701 5205821 2 Price 39 99 6 48 29 99 0 85 0 85 4 32 S4 66 2 60 2 30 31 99 24 90 13 80 2 40 2 40 0 49 1 34 2 75 0 61 1 16 0 56 0 41 1 42 0 61 0 42 33 00 24 00 Total Ext 39 99 6 48 29 99 0 85 S0 85 8 64 9 32 2 60 2 30 31 99 24 90 13 80 2 40 2 40 0 98 4 02 5 50 1 22 1 16 1 68 1 23 14 20 3 66 2 52 33 00 24 00 269 68 26 Solar Panel 9 lt k kA E PP PP PP N Q P P kA P P P Part Name Voltage IC C1 2 3 4 C12 C7 C8 CO C6 11 13 L1 2 3 4 R1 3 R2 R4 R5 D1 2 3 4 Solar panel PCB Fabrication Mfr Part SPV1020 GRM188R71C104KA01D C1210C475K5RACTU GRM188R71A474KA61D GRM188R71C223KA01 C1608C0G1H221 C0805C475K4RACTU B82477G4473M ERJ 6GEYJ305V ERA 6AED2553V CRO805 FX 7872ELF 292 1 0K RC MBRS340 Value 100nF d Zut 470nF 22nF 220pF 4 7uF 47uH 3mOhm 255kOhm 78 7kOhm 1k Cost EA S 11 57 S 0 25 S 0 77 S 0 10 S 0 10 S 0 16 S 0 37 S 2 03 S 0 07 S 0 09 S 0 10 S 0 04 S 0 61 S 300 00 S 33 00 Cost 358 74 27 User Interface Qty P P PS A DM OO HI WN IO IQ QO QO QO P U WNNN N GQ N NY WN N W Part Name 100 uF 50V Capacitor 100 uF 25V Capacitor 470 uF 16V Capacitor 60V Schottky Diode 2200 uH Inductor 1000 uH Inductor 2 0k Resistor 3 4k Resistor 12 7k Resistor 200k
3. a middle neutral position that ignores the throttle input When reverse is selected the motor controller sounds an external buzzer and energizes the field in the opposite direction to make the motor spin the opposite direction from normal Speed of the car is limited to a much lower value when it is in reverse The LCD screen will display speed in an electronic gauge battery state of charge battery and ambient temperature time and a reverse detection system When the car is in forward there are two possible modes in the controller The mode select switch is used to switch between these two modes Hi mode is the standard full soeed mode For testing a maximum speed of 25 MPH In LO mode the controller limits the speed of the car to 10 MPH and increases the throttle sensitivity to improve handling in a crowded setting The hand throttle outputs a voltage range between roughly 0 7 and 4 3 volts as measured on the signal wire when given a voltage of 5 volts The controller provides this voltage It is a solid state throttle using a Hall effect sensor chip to vary the output voltage with respect to the position of the handle which is more sophisticated than a simple potentiometer throttle but more reliable This throttle was salvaged from a Chinese built bubble car type vehicle that Paragon purchased for the team to disassemble and rebuild Additional Non Functional Options Two added features will be included for the protot
4. audio signal to the speakers The amplifier for the internal speakers is a 2x15 watt stereo class T TA2024C amplifier board The amplifier for the external speaker is a 2x50 watt stereo class D TDA7492 amplifier board we use only one of the two available outputs on this amplifier Pre designed amplifier boards are used to save on time and expense By default both the internal and external amplifiers are powered and the audio signal connected to the generic 3 5 mm headphone jack is passed to the internal speakers If the microphone switch is pressed the NAND logic sends a signal to the audio switches to pass only the microphone signal to the external speaker amplifier until the switch is released If the Bluetooth switch is pressed the NAND logic sends a signal to the audio switches to pass only the Bluetooth signal to the internal speaker s amplifier until the switch is returned to the off position K Speaker Cable 4 ei A AE ELEA ORN aeS V ELE lt Aualo Selection x 3 5 mm male to An male audio cable Lene Ter Sound Input Device via 3 5 mm jack Bluetooth Adapter Accept Music Input Hands free Calling Figure 7 Audio System Block Diagram 10 Sen H H H H H H wl i k 4 i H La TE eh 4 al Kr T p r co aT H H En H K i I i 4 t H HJ eH oA Figure
5. of such size that they could be plugged directly into the board and powered read The individual components were not able to be tested on a breadboard due to their very small surface mount size and a lack of time to prototype the devices out As a result of this 17 many shortcomings and omissions were noted during the testing phase that were accommodated by soldering jumper wires onto the PCBs The PCB designs themselves have been updated with the shortcomings found during testing addressed During assembly it was found that the datasheets listed incorrect sizes for several of the parts such as the inductors for the voltage convertors For some parts it was possible to make them work for the prototype and the board designs were updated with the correct sizes for the components The speed sensor amplifier custom board was abandoned completely as the chip was far too big for the laid out pads and would not work as configured and a prototype buffer board was constructed using parts on hand including a basic 741 type operational amplifier and a prototyping board Under testing of the temperature sensors it was found that the sensors predictably and accurately registered the air temperature and responded appropriately with a rise in indicated temperature Testing of the speed sensor buffer showed that it was properly transmitting pulses Testing code in the Arduino successfully managed to both return a temperature for the sensors and calculate a
6. speed based on the pulse rate coming from a function generator The IR sensor was not yet able to be tested as it had not yet arrived from the supplier Also during testing it was found that the serial communication port was connected to pins on the LCD panel s connection plug that cannot be used for serial communication they are reserved for USB To test the data link the connecting traces around the pins were scratched off and jumper wires were soldered to the pins to enable a data path for testing The Arduino was able to send data to and refresh the LCD panel s meters A bidirectional link was not tested Future Work As previously noted the PCBs are in an early prototype state and need to be further revised and refined to support additional sensors if desired The schematics and board layouts in this document show a revised version that may undergo further revision as more testing is done Also the Atmel ATMega328 microcontroller with the Arduino software could be integrated into the main board for a more compact solution Alternative sources for a touch enabled LCD screen could be investigated as well as more elegant means of interfacing with it 18 Cost Breakdown The production cost goal was 2 000 The actual cost was a bit higher than that but this was the prototype The cost breakdown is below Jser Interface i R w eye E Drivetrain m Lighting Le Figure 17 Cost Breakdown The tota
7. system The blinker system is controlled by a simple 555 timer set off of a Hz frequency The output of this goes through a MOSFET which is controlled by the blinker switch This is then routed to the relays that control the blinkers NOTE The rear blinkers will oppose the front blinkers which are the halo lights The lighting system has an added 5V bus which is used to charge the user s cell phone and the Bluetooth dongle via USB This is regulated by a buck converter capable of 3 amps Lights Controller Hote Front Blinkers are Halo lights around the headlights They are on by default and blink apposing the blinkers Buck Converter EVIA Blinker Relays gt Blinkers Figure 4 Lighting System Block Diagram AUTO LIGHTS 470K R2 GND PB1340067 K2 D6 a GND ve 1 1 RIGHTHALO x1 D gt ry 2 a BRAKE BRAKE 1 8 kees 9 E SI 3 2 va 1 1 4 GND RE LEFTHALO I LB GND LB RIGHTHALO ots RBS a gt LEE THALO B1 A BRAKRRAKE L LBS Ge x2 EN ots GA Ge G al se 2 g GND i ST Buck Converter Ge GND SYOUT C C2 C3 0 1 uF de LE GND Blinkers LBS Nw 58 jot uF GND Ok 11 0 1 uF GND Figure 5 Lighting System Schematic V2 1 BRAKE BRAKE 1 BRAKE R BRAKE L NN SN A HTHALO HTHALO yn el LEFTHALO n F L J Figure 6 Lighting System PCB Layout V2 1 Headlights Tail ligh
8. the ezLCD 313 user s manual located at 22 Appendix B Bill Of Materials Lighting System Qty P PM NN NOS P BPP BR GQ P NAN NPN N ODO NOTE This does not include the physical lights Part 470 kQ Resistor N channel Mosfet Depletion Mode N channel Mosfet Buck Converter 47 uF Tantalum Capacitor Relay SPST Schottky Diode 1 uF Ceramic Capacitor 10 kQ Resistor 47 UH Shielded Inductor 555 Timer 1 kQ Resistor Standard Diode Power Mosfet 220 kQ Resistor USB Connector Relay DBDT Handlebar Light Switch RELAY GEN PURPOSE SPDT 20A 12V Standard Diode PCB Manufacture Part ERJ 6GEYJ474V CPC5602CTR 2N7002LT3G AP1507 50 T491D476KO20ZT PB134005 SS3P3 M3 84A CO805C104K4RACTU ERJ 6GEYJ103V CDRH127 LDNP 470MC NE555D ERJ 6GEYJ102V GF1B AOD484 ERJ 6GEYJ224V 292303 1 RT174005 N A Amp Relays S1G E3 5AT Price 0 10 0 88 0 15 2 36 1 08 1 49 0 60 0 11 0 10 1 35 0 44 0 10 0 49 0 58 0 10 1 44 2 50 S 34 95 S 4 32 S 0 54 S 33 00 Total Lt Lt Lt Let Lt Let Lt Lt L t YN Lt Let L t Lt YN WY YW Price 0 60 1 76 0 30 2 36 2 16 2 98 0 60 0 33 0 40 1 35 0 44 0 40 0 49 1 16 0 40 2 88 5 00 34 95 8 64 S 2 16 S 33 00 102 36 Lt Lt Lt Let Lt Let Lt Lt L t Lt Lt Let L t Lt YW OY OW Lt U gt 23 Frame and Drivetrain HOME COST ESTIMATION Electricals 2 512 33 neue 1 637 05 Item Supplier nitial Inv Initial Investment T
9. the solar panel so far the PCB testing is still in process This consisted of taking the solar panel outside on a sunny day checking the output voltage and the power output The first round of testing on the PCB presented unexpected results After further testing it was discovered that the symbol and package had the pin numbers in the reverse orientation causing the chip to be soldered to the board up side down Before testing can continue a new chip on order must be installed Future Work For future work three or four more solar panels could be added such that when the cart is parked the panels can be unrolled to charge the batteries faster and more effectively because of the increase in solar capture This would utilize a key feature of the SPV1020 using it in a panel array Also a redesign of the current PCB may be in order if a larger solar panel is desired User Interface The User Interface utilizes an EarthLCD ezLCD 313 touch screen and an Arduino Uno microcontroller board to relay information to the driver of the vehicle The information that will be available to the user will include speed battery life and outside temperature The Arduino also uses an additional 14 temperature sensor to monitor battery temperature and an infrared sensor to measure the distance of objects behind the vehicle PCBs were designed to interface between the Arduino the LCD screen the various components and supply power to the devices To supply t
10. 8 Audio System PCB Schematic Version 6 BLWETOGTH za EI WW J e J JI lilii Figure 9 Audio System PCB Layout Version 6 11 Boston Acoustics Internal Speakers Jensen Waterproof External Speaker GOgroove SMARTmini AUX Bluetooth Adapter Permanent Cart Microphone 2x15 Watt Stereo Class T TA2024C Amplifier Board 2x50 Watt Stereo Class D TDA7492 Amplifier Board Testing Testing was done on version 4 of the PCB This consisted of supplying 5 volts from a lab power supply applying a 40 mVpp 300 Hz sine wave from a frequency generator to each 3 5 mm audio jack one ata time and connecting an oscilloscope to the signal outputs Also 5 volts was applied in succession and in combination to each input to verify the logic was working as intended 12 Unfortunately it was quickly found that the two power MOSFETs not shown that were intended to switch on and off the amplifiers would not operate under the given conditions With Vps 12 V or 24 V and Vss 5 V the intended ON state the MOSFET could not turn on Since these MOSFETs were included in the original Boolean expression to create the circuitry this mistake has caused some functions not to operate as intended e g passing the 3 5 mm generic input to both the internal and external speakers Testing of the other parts was more successful Powering the amplifiers with lab power supply s inputting a small signal from a frequency generator and connect
11. Paragon Pack Rabbit Design Document Group May13 22B Team Team Membere e Adam Woody Team Leader e Nick Marquardt Webmaster e Kevin Flynn Communications e Andy Goiffon Team Representative e Chris Larson Team Representative Table of Contents ENEE eege 1 System Design E TE NEE 1 iii On e e uuu masan N EE E 1 MOr eine E 1 Ville ee H BMY E 2 Non un Gona DO EE 2 Brot 2 Lori u uu u au uu m 2 Z aun ma na uns 2 Additional Non Functional Options EE 3 Detailed System Description 4 Motor Controlle EE 4 TO li 2 E E E E u EEA 6 HENUA SY SU SIN oaa A E EA E 7 PESU EE 9 FUO WOTE EEN 9 BUS de ege ICO Syste E 10 TO SING 0 unn nn un ona DS S S ns s a Sanu es 12 Hi Or u E ua E 2 u a us 13 EE ee 13 Te nn unn u 2 u Sua nn u u 5 14 FP IS 0 u u u u u n uu E u n 14 Be Ia e 14 Toi EE 17 Fi rO NOI EE 18 OSU Bi Ca GOW i E 19 NERT 19 Lee E e UE 20 Appendix A USEF S ELL 20 DEVETA NEE 20 Bregen EE 20 Atl IO y SIG a uum nia E na sansa assum sss sabaha qasan s 21 Sailen EE ER sern 6 ie Gl u usu ua upa su ak error en meer eee oe t umawa 22 Appendix E UE E E 23 HENNE SySTSlWNTY u y yn u n uSDa tidal iit athe tai hal ad abated aa Sua Sa Su kasuna 23 Fane ele DUVE aN DEE 24 ele SY SECM EE 26 SolarrPanel EE 27 ES Se MRS ri uuu ul 2 Ee 28 Executive Summary The purpose of this project is to design and build a small electric vehicle w
12. Resistor 2 0M Resistor 1 amp Buck Regulator 3 pin Connector vertical 3 pin Connector horizontal Power Connector 2 pin Connector 6 pin Connector 8 pin Connector 16 pin female Connector Power Plug Contact for power plug 3 pin Plug 2 pin Plug Temp Sensor IC Op Amp Arduino ezLCD 313 PCB Fabrication Mfg Part No EDK107MOS50A9MAA AVE107M25X16T F AVE477M16G24T F SS16 E3 5AT SDR1005 222KL SDR1005 102KL ERJ 3GEYJ202V ERJ 3EKF3401V ERJ 3EKF1272V ERJ 3GEYJ204V ERJ 3GEYJ205V TL2575 ADJIKTTR 640454 3 640457 3 1877285 2 640454 2 68001 406HLF 68000 408HLF DF11Z 16DS 2V 20 1 1123722 2 1123721 2 3 640443 3 3 640623 2 LM61CIM3 NOPB MCP6001UT I OT A000066 ezLCD 313 Price 0 70 0 21 0 51 0 52 0 64 0 64 0 10 0 10 0 10 0 10 0 10 1 91 0 17 0 17 0 30 0 13 0 34 0 27 1 66 0 16 0 21 0 20 0 16 0 93 0 29 27 83 219 00 33 00 Total Ext 2 10 0 42 1 02 1 56 1 28 1 28 0 30 0 20 0 20 0 20 0 20 5 73 0 85 0 68 0 90 0 39 1 02 0 81 3 32 0 48 1 05 1 60 0 48 2 79 0 58 27 83 219 00 33 00 276 27 28
13. Throttle Motor Controller lli Power Source 1266 SepEx n Ignition Switch Mode Select Fwd Reverse devices A block diagram for the motor controller is below Armature Motor D amp D 3 5HP Figure 1 Motor controller block diagram get r D Jain Contactor VVinding z Adam Contactor Lic lsc Lea FEI Motor Figure 2 Motor controller schematic The following are pictures of the actual components for reference s s ae Ke La MOTOR SYSTEMS se Seo V V Heicht dr Troan J185H AC j Testing The following figure is testing under LO Mode conditions This is from the Fall 2012 vehicle design Monitor SPEED INPUT Monitor THROTTLE 20 dal Uhu LL 52 48 0 53 31 2 54 14 4 54 57 6 55 40 8 56 24 0 57 07 2 57 50 4 58 33 6 59 16 8 00 00 0 20 120 100 Monitor ARM CURRENT Monitor FIELD CURRENT T T T T 52 48 0 53 31 2 54 14 4 54 57 6 55 40 8 56 24 0 57 07 2 57 50 4 58 33 6 59 16 8 00 00 0 Figure 3 Charts of current and speed over time during a short test trip After installing the motor controller and batteries into the frame produced by the mechanical engineering team a test trip was made This short trip involved no serious inclines but was
14. gn plans Also a detailed explanation of what is wrong with the current system and how to fix it is included Drivetrain The motor controller needs reprogrammed for the new vehicle The batteries are capable of safely extracting 175 amps of current The 2 modes need to be programmed This is done with a dongle and a program for easy use See Jim Heise Professor in the Mechanical Engineering department for these Likewise the entire system is wired and connected It would be beneficial to add conduit and wire the vehicle more elegantly A key switch with extra poles could be very beneficial as well to power to a relay in order to tap into switched power Lighting System The current lighting system has not yet been tested This is because the car was not finished in time so it is unknown for sure whether the system works or not Alternatively a new PCB could be manufactured to add the MOSFETs to the blinker relay coils to put less strain on the 555 timer If this option is taken please note The input output terminals should be redesigned A connector for each power input should be selected as well as eliminating ones that are not needed The Inductor has the wrong package size as well This should be fixed before the next ordered A case with connectors that are waterproof would be ideally integrated Make note of the current Capacity of these connectors They need to be able to carry 15 amps apiece Under the current circuit the batteries w
15. hat it complies with specification is essential Battery The charging station team is mostly responsible for the batteries in terms of charging and monitoring their state of charge However the batteries used influence how our system operates The batteries chosen are a set of three Trojan 215 AH flooded lead acid batteries These batteries are capable of sustaining about 150 amps of current output for around an hour and a half under absolute worst case driving Real world driving suggests around five hours of run time Non functional Design Lighting The vehicle s lighting system while not a functional component is necessary in order for the car to meet regulations to be licensed as a moped per the request of Paragon Lighting will be LED headlights taillights and blinkers The blinker system based around a simple 555 timer circuit will provide a pulsing output to lights which are meant to blink as opposed to steady lights such as the headlamps tail lamps and brake lamps User Interface The switches and other controls along with the throttle handle are located in the front handlebar area This puts all of the controls within reach of the driver during normal use Controls include a forward reverse selector switch a mode selector switch and ignition switch a lighting switch for automatic headlights and turn signals a hand throttle and a touchscreen LCD display The forward reverse select switch is a 3 way toggle with
16. he power buck converters are used to reduce the 36 V from the batteries to 9V to power the Arduino and 3 3V to power the LCD For connecting all of the components together plugs connectors and wires were selected to make component placement as versatile as possible The EarthLCD ezLCD 313 was selected as the display primarily due to its features It contains its own onboard microcontroller logic and widget library making programming the graphical interface components much less time consuming and not as daunting of a task to a group with very little experience in this type of programming All of the commands sent back and forth between the Arduino andthe LCD are ASCII text sent over a TTL serial link The link is bidirectional so that touchscreen button taps can be relayed back to the Arduino for processing The temperature sensors are Texas Instruments LM61CIM3 temperature sensor ICs These sensors were selected due to their small surface mounted package size as well as their predictable linear voltage output As opposed to other forms of temperature sensor such as thermistors or resistance temperature detectors RTDs the LM61 type device provides a precision temperature output with no calibration required The sensors take as a voltage supply 5VDC generated by the Arduino s onboard regulators and are read by analog to digital convertors that are integral to the Arduino microcontroller package The microcontroller s analog to digital conversio
17. igh amount of power and as such relays are used to route appropriate current to the various lights on the vehicle The logic that controls the relays is controlled by some basic MOSFETs and a few depletion mode MOSFETs which are on by default and turn off when a voltage is applied to the gate The power demands to the system are very high The headlights themselves require 15 amps each A similar story exists for all of the other lights most requiring 7 5 amps to run at a visible level Due to this fact and the fact that a unbalanced State of Charge SOC on the batteries can cause a decreased run time each headlight is run off of a separate battery while the brake lights and blinkers run off of the third battery in order to maintain a nearly balanced SOC The automatic headlights work when certain conditions are met First the switch on the handlebars of the cart must be in automatic mode and the key switch must be on Secondly the solar panel input is connected to a depletion mode MOSFET which detects if the solar panel is providing voltage The solar panel at a certain level of low light will not have enough solar energy to output any voltage or current around an estimated 20 of full sunlight This allows the FET to turn on and pass current to the coil of the headlight relays under the low light condition The halo lights around the headlights are on by default When the user applies the turn signal the halo will then flash using the blinker
18. ill go out of balance eventually This should be addressed somehow The reason we did not use a buck circuit in the current configuration is because of loss expense and power capability There is a definite compromise by tapping 3 separate batteries but it seems to be the best A battery balance system would be helpful The brake lights are not included in the PCB properly and should be redesigned The headlight on option rather than auto is currently planned on being implemented by off board relays The coil is run by the on switch and the batteries go through the contactor to the lights 20 Audio System The audio logic did not work The error was that the gate voltage was not higher than the source to drain voltage so the MOSFETs never turned on The current strategy to eliminate this problem is to integrate relays with the MOSFETs to power the amplifiers This and other problems can be seen in the figure below Everything that is circled is necessary changes to have a fully operating board as intended 2 E Enlarge ALL Drills Holes to Match Amp Boards around 0 125 it ar i Sound sianal Sound INTERNAL OL LESS RESESESES ESE RESRESESSEESSES ESSE SESE SES ESSESES SESE EERE SESE SRESE SESS ESSERE SES ESSESR SESE SS SEE SS ES EE OS See PSS ESSE ESS SEES S ESSE SPSS SSE Relay for Ext Power e lt TO Int Power Input Ext A
19. ing an oscilloscope on the output we saw the amplifiers were operating correctly We then proceeded to connect the speakers to the amplifier outputs Then the PCB amplifiers and speakers were connected together It should be noted that at this stage the MOSFETs discussed earlier were bypassed and the amplifiers were powered directly from the power supplies Readings on the oscilloscope were erratic and the sound was very unpleasant Soon a resistor on one of the amplifier boards was a block of carbon and we quickly turned off all power After investigation of the mishap it was found that two distinct grounds existed in the circuit causing major transients The burned resistor was replaced and testing recommenced but with only one ground Once this setup was successful the microphone and Bluetooth adaptor were both tested by plugging them into a computer s microphone port and recording the input Each performed admirably Future Work As noted in the captions for the audio system schematic and PCB layout version 6 is shown It was necessary to modify the tested version for reasons discussed earlier These modifications included removing the power MOSFET switches and useless NAND gate circuitry However these modifications have given an underperforming design For future work a redesign of the NAND gate circuitry is necessary to accommodate the missing MOSFETs Once a new Boolean expression is derived an even simpler and smaller NAND gate circ
20. ith a 25 mile per hour top speed and an operating endurance of about four hours for the Paragon company This car will be built on a custom frame assembled by the mechanical engineering team and will use component already purchased for the project The car will be used as a multipurpose vehicle in a fair or carnival setting on relatively flat terrain System Design Requirements The primary requirement of the design of the vehicle is that it must meet day to day needs in a carnival environment including such activities as stocking concessions with supplies carrying passengers and gear to various locations in an amusement park or fair and to serve as a first aid response vehicle In most cases the car doesn t need to travel faster than 5 to 10 miles per hour but it is required to have a top speed of up to 25 miles per hour It should be able to carry a driver as well as an additional adult passenger or as much as 250 pounds of gear or supplies Functional Breakdown The functional requirements for the vehicle are met by the motor controller and motor provided to the team by the mechanical engineering team This consists of a Curtis 1266 SepEx motor controller and a D amp D Motor Systems class H separately excited DC electric motor The motor will provide enough torque and capacity to propel the vehicle at the desired speeds over relatively flat terrain There is also a function select switch that will change the operation of the controller from a fu
21. l cost for all electrical systems was 3 578 61 The other teams spent an additional 2 237 05 bringing the total prototype cost to 5815 66 In production quantities we expect to save around 40 which comes out to an estimated total of nearly 3 500 This is well above the desired production cost but 650 of that amount is optional as well as future proposed savings on the user interface can bring down costs to a reasonable level The individual cost breakdowns can be seen in the Bill of Materials in the index of this document Design Review This design details the building of an electric vehicle that meets the given functional and non functional requirements from the client Paragon It will in its finished configuration be able to reach a 25 mile per hour top speed and will have an operating duration of as long as four hours It will be a fun little vehicle for Paragon that matches up well with their corporate philosophy of being a manufacturer of fun 19 Appendices Datasheets for components used in the construction of the car as well as some that were considered for use but were later decided to not be suitable are located on the team website at http seniord ece iastate edu may1322 Appendix A Users Guide This section is intended for the next engineering segment of the design as the system has not been fully completed It will be subdivided into segments detailing what is the logical next step to take under the current desi
22. ll soeed mode to a speed limited mode for use in situations where the car is in a large crowd of people or it is otherwise not desired to drive at full speed Motor Controller The Curtis 1266 SepEx motor controller is commonly used in golf carts and utility carts It works with a separately excited motor to provide a forward and reverse setting as well as a secondary forward setting In the case of this project the secondary setting is used for a reduced speed mode The controller is capable of providing up to 275 amps of current to the armature windings and up to 20 amps of field current The controller interfaces with the motor through a main contactor a type of relay that connects and disconnects the armature of the motor to the output terminals of the controller The main contactor is used for safety reasons as the controller will detect particular faults and disengage this device to stop the motor It is also the primary means used to engage and disengage the motor s operation during normal use Regenerative braking is handled by the controller through energizing the field windings with current in the opposite direction to normal use This turns the motor into a generator and allows the forward momentum of the car to recharge the battery during deceleration and braking As this is a standard feature of this type of controller no additional system level design needs to be done in order to implement this desired feature Inputs to the co
23. mp Int Amp Voltage Voltage 12 V currently TO Ext Amp Power Input Figure 18 Modified Version 1 3 with Changes Needed to have Fully Operational Board The current version of the PCB V1 6 has the correct dimensions to mount the amplifier boards This should NOT BE CHANGED NOTE The physical board that exists is V1 4 There are significant differences between 1 4 and 1 6 A new board should be designed as neither of these versions will work The screw holes and board size are correct The circuit needs redesigned but the dimensions shouldn t be changed The current plan is to use standoffs to mount each board atop the other A case with connectors is 21 required weatherproof The 15 watt amplifier should be upgraded to make the internal speakers more audible Under the current amplifier the output cannot be bridged into one speaker Only one channel can be used Solar Panel When testing the PCB the SPV1020 is not boosting the input voltage We tried trouble shooting this by testing the continuity of the diodes According to the datasheet if ILOAD 0A then Vout Vin To test this case we applied a load and measured the voltage and Vout Vin We also recalculated the values of R1 R2 R3 and R4 to verify they are correct The next step you could take is to try and bread board the circuit and trouble shoot it If that doesn t work redesign the board from scratch around the SPV1020 and see if you get a similar board When ordering
24. n has sufficient resolution to read the temperature accurate to within approximately 1 degree Fahrenheit or 0 5 degrees Celsius The infrared distance sensor used to detect objects behind the vehicle is a Sharp GP2YOA21YKOF infrared sensor It is capable of sensing objects at distances from approximately ten centimeters to approximately 80 centimeters The sensor itself is located inside the rear bumper of the car protected from the outside elements by a piece of transparent plastic The sensor outputs a voltage that varies inversely with distance The approximate distance to an obstacle is reported to the user in either inches or centimeters when reversing and the display will present a warning when an object passes inside a threshold distance This system was included due to the lack of rear visibility in the vehicle with cargo loaded To sense forward speed to report a speedometer value to the display unit the Arduino module takes output from the Hall effect speed sensor packaged onto the motor Since all of the coupling between the motor and the wheels of the vehicle is directly through belts and shafts with no clutch or fluid coupling motor RPM can be converted directly to vehicle forward speed through a formula The Arduino s code counts pulses and times the intervals between successive revolutions to determine the motors RPM A proportionality constant is then used to convert the resulting speed into either miles per hour or kilometers per hour
25. ntroller are mostly through switches There are switch inputs for the forward and reverse selectors the mode selector and the ignition key switch There is also a switch input for a pedal interlock When this switch is opened the controller will ignore throttle input This switch input will be wired to the brake handles so that in the event the user applies one or both of the brakes the throttle signal to the controller will be interrupted It will not directly cut power to the motor but will rather engage the regenerative braking action to allow the motor to assist in slowing down the vehicle Motor The D amp D Motor Systems 7 5 horsepower motor is a class H separately excited DC electric motor Its intended purpose the same as the motor controller is to be installed on a golf cart or other utility vehicle The field and armature windings are separate terminals on the motor body so that each can be independently energized by the controller This allows the motor to spin in both directions by reversing the polarity of the field winding which also enables regenerative braking The motor like many other electrical components is capable of consuming more electrical power and delivering more mechanical power than it is designed Care must be taken in the programming of the controller to ensure that the motor s ratings are not exceeded Since the controller is capable of producing way more current than our motor can handle programming to ensure t
26. on a real world test environment The motor s armature current jumps rapidly to the full 150 amp limit when the throttle is twisted to max but when the full forward speed is reached the current required to maintain speed drops to less than half of the acceleration current On a downhill slope since the controller will maintain the motor speed rather than its power output current will instead flow into the battery as regenerative braking The regenerative action can be seen in the graphs in Figure 1 as the points where the motor current dips negative This current is flowing from the motor into the battery partially charging the batteries Due to the construction of the sealed lead acid batteries in the testing configuration the current to charge them is severely limited by the voltage limits of the cells The controller limits regenerative current based on battery voltage levels During testing the motor controller s features were very helpful as it includes the ability to log data as seen above This obviates the need to have a separate data logger attached to the operating system Instead the same controller connection used to program the parameters of the controller can be used to monitor its operation with a laptop or other portable computer device The controller does not have any internal storage of its own however so it must be connected to the programmer in order to log data Lighting System The automatic lighting system uses a h
27. ooling for Non Cost per part Standard Parts Total Cost Per Part Expecte d Cost Cost D amp D 93B 48 475 00 429 88 429 88 475 00 1266 Controller Bohlingers 1 409 89 70 286 92 286 92 409 89 Front ScooterPa Wheel cA Bee 145 00 58 00 58 00 145 00 Assembly Buggies 109 98 65 99 131 98 919 96 TWA8 Rear Wheel dei Unlimited P365M Small 355M Smal unn 50 2447 an 89666 83 94 41 97 83 94 167 88 P1125 Large Front Brake DECH 99 00 4950 49 50 99 00 Assembly Rear Brake ScooterPar Assembly SCT I 40 00 40 00 80 00 Jack Shaft Custom Assembly 40 00 40 00 40 00 40 00 Rear Brake Northern Rotor 26 99 70 18 89 37 79 53 98 13829 SE 2499 70 17 49 34 99 49 98 Adapter Custom un ema s1000 us Northern 1369 Rear Axle Tool Peerl 1 119 99 70 83 99 83 99 119 99 ess Gear SU n 1661 50 8 31 16 61 33 22 Taper Lock 2 11 38 50 5 69 11 38 22 76 EE N 50 50 50 lt O O O cO N E CS Ete EET TT Ett ft face 24 Bushing 7 8 Bushing 7 8 Gates 2 12 48 50 624 1248 24 96 SE SC EES ee 12 77 50 6 39 19 16 38 31 a 6244K5 Ball Bearing McMaster 2SWK1 ion TE 31ALi0 9 Connectivit 1 44 20 50 37 90 37 90 44 20 Switch F R N NKK C1510 HELO as Switch Acrolectric 4 64 4 10 4 10 4 64 Hall Effect Hand Cloud ES 00 21 00 21 00 42 00 Electric Thr
28. ottle Cabling McMaster Connectors Sc Tell se sem som Lights Estimate 1 220 00 90 198 00 198 00 soun E 518 19 350 95 Axle and Differential 119 99 Speed Controller 409 89 38 530 54 25 Audio System Qty A PP P N N P kA P P P DO QQ P N N Q N P P gt O e al O IO Part Name Internal Speakers Rocker Switch On Off Mom JENSEN 6 5 Coaxial Waterproof Speaker SWITCH ROCKER SPST 10A 125V SWITCH ROCKER SPST 10A 125V RELAY GEN PURPOSE SPDT 20A 12V KNOB CLR GLOSS 925 DIA 250 SHAFT CONN JACK MONO 3 5MM OPEN CIR EXT eForCity VOIP SKYPE Mini Flexible Microphone Black GOgroove SMARTmini AUX Bluetooth Car Kit with Handsfree Calling Wireless Music Streaming 2x50W TDA7492 Class D Amplifier Board T Amp Tripath TA2024 2x15W Audio Digital Amplifier Board 100K Audio Taper Stereo Potentiometer 1 4 Shaft 50K Audio Taper Stereo Potentiometer 1 4 Shaft IC GATE NAND QUAD 2INPUT 14 SOIC CONN AUDIO JACK 3 5MM STEREO SMD Male to Female 3 5 mm cable IC SWITCH BUS 4BIT TTL 14SOIC TERMINAL BLOCK 5MM VERT 7POS PCB Blue TERM BLOCK 2POS SIDE ENTRY 5MM Green TERMINAL BLOCK 5MM VERT 2POS PCB Blue STDOFF HEX M F 4 40 2 00 L ALUM MACHINE SCREW PAN PHILLIPS 4 40 HEX NUT 0 184 STEEL 4 40 Fabricated PCB Cable wire connectors Mfg Part No SE45 7107J61ZQE22 MS6007S SRB22A2BBBNN SRB22A2DBBNN T9AP5D52 12 OEJL 90 1 5 35PM1 AA AB32174 TA2024 023 652 023 650
29. the PCB it might be in your interest to get a solder paste stencil for all the small components Similarly alternative diodes need to be chosen and added as the ones on the BOM are no longer available A weather proof case and connectors for the PCB will need to be chosen The solar panel itself definitely works and has been thoroughly tested User Interface The original LCD interface board has the serial link going to pins that cannot be used for serial I O This has been addressed in the PCB layout designs in this document but the original prototype boards are based on an old revision and are not correct To use the prototype board jumper wires have to be connected directly to the pins on the interface plug More GPIO pins can be added for accessing to allow room for expansion On the Arduino board GPIO pins are also broken out for access in the latest revision Additional work for the microcontroller includes giving the Arduino the capability of collecting other signals such as reverse status whether or not the headlamps or blinkers are on etc Any of these types of signals would need to be buffered in order to not damage the Arduino s input circuitry A weatherproof case should be sought for enclosure of the Arduino The LCD contains macros defining the home screen in US and Metric units along with a pair of macros that set and clear a generic warning indicator Full instructions for programming of the LCD user interface are located in
30. ts Handlebar Mounted Switch Testing Due to the high power and complexity of this system testing must be done on car Version 1 of the board never made it to build level It was revised to include an automatic headlight system Version 2 0 of the board was ordered and then retrofitted to include the relay coil discharge diodes as shown in version 2 1 Future Work To reduce cost a few lights can be eliminated The rear blinkers can be eliminated and the brake lights can be repurposed as blinkers and brake lights There may be a problem with using the 555 timer s output to directly control the blinker relays The coil should be controlled by a MOSFET that turns on from the 555 timer s input A blinker clicker should also be added and the frequency of the blinker should be increased to 1 Hz Bluetooth Audio System The Bluetooth audio system works under the premise of Boolean logic on a PCB Audio Selection Center in the block diagram below Two quad 2 input NAND gate ICs Fairchild Semiconductor MM74HC132 Quad 2 Input NAND Schmitt Trigger take in the switch signals and then output signals to the audio switches The audio switches Fairchild Semiconductor FST2126 4 Bit Bus Switch simply allow the audio signal to pass or not Audio signals enter the system through three separate 3 5 mm audio jacks The audio jacks connect to a permanent cart microphone a Bluetooth adapter and a generic 3 5 mm headphone jack Two amplifiers are used to boost the
31. uitry will emerge Also power for the amplifier boards need not run through the PCB itself they can be powered in a similar fashion to the PCB through relays Finally an upgraded amplifier for the internal speakers similar if not identical to the amplifier used for the external soeaker would be recommended for greater entertainment Solar Charging The Solar Charging system is comprised of two parts The first part is a custom made solar panel made for us by PowerFilm It has an output of 30 watts at 15 4 volts and is 23 x 50 It was designed to be an all weather panel that is light flexible and very durable Also this solar panel performs very well in low light conditions The second part is the PCB which was designed around the SPV1020 a DC DC boost converter with an operating voltage of 6 5 40 volts with a maximum power capability of 320 watts It also has overvoltage overcurrent and thermal protection built in The most important built in feature of this chip is the MPPT algorithm that gives the DC DC boost converter up to 98 efficiency An adjustable switching frequency 13 of 50 200 kHz and a duty cycle of 5 90 with a 0 2 step are utilized to achieve this maximum rated efficiency Solar Cells Power Film Figure 10 Solar Charging Block diagram Figure 11 SPV1020 PCB Layout Figure 12 SPV1020 PCB Schematic Testing Testing has only been completed on
32. ype which are planned to be options as chosen by the end user The first is a Bluetooth Audio system with internal external speakers The internal speakers are 4 Boston Acoustics two way hi fidelity speakers The external speaker is a 6 Jensen waterproof speaker which is necessary to combat the elements The system is designed to take inputs from a Bluetooth enabled device such as a cell phone an in car mounted microphone and a 3 5 mm audio jack The Bluetooth audio will be routed to the internal speakers only so as to avoid broadcasting a private phone call while using the hands free feature The in car mounted microphone will be activated by amomentary switch allowing the user to broadcast information to the surrounding area A device connected to the 3 5 mm audio jack will be switchable between the internal and external speakers The other is a large flexible solar panel sourced by PowerFilm Solar This is able to provide 30 watts under full sun to modestly charge the batteries A system was built in order to extract the maximum power out of the solar panel under any condition by way of Maximum Power Point Tracking The system also boosts the voltage to usable charging levels Detailed System Description Motor Controller The motor controller itself is also wired rather simply with heavy 2 gauge wires providing the armature current and lighter wiring for the field winding and also to provide signal input from the peripheral Hand
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