1. 1

2. SAE Formula Car Display and Data Acquisition System SAEDAQ Caleb Davison Phil Jacher George Kontos Advisor: Mr. Gutschlag 2

3. Overview Summary Summary Measurement Strategies Measurement Strategies LabVIEW User Interface LabVIEW User Interface Microcontroller Microcontroller LCD Screen LCD Screen Wireless Chips Wireless Chips 3

4. Overview Summary Summary Measurement Strategies Measurement Strategies LabVIEW User Interface LabVIEW User Interface Microcontroller Microcontroller LCD Screen LCD Screen Wireless Chips Wireless Chips 4

5. A Typical Car… 5

6. SAEDAQ Summary Society of Automotive Engineers Formula One racecar Society of Automotive Engineers Formula One racecar Data recording Data recording wheel speed wheel speed engine rpm engine rpm oil pressure oil pressure oil temperature oil temperature coolant temperature coolant temperature Data will be transmitted to the cars dashboard and an off-track laptop Data will be transmitted to the cars dashboard and an off-track laptop 6

7. Previous Works Project has been attempted several times Project has been attempted several times Never been able to coordinate with MEs Never been able to coordinate with MEs Most recently last year with Justin Peters Most recently last year with Justin Peters Using different MCU, upgraded wireless chips Using different MCU, upgraded wireless chips New dashboard design New dashboard design 7

8. High Level Block Diagram 8

9. Overview Summary Summary Measurement Strategies Measurement Strategies LabVIEW User Interface LabVIEW User Interface Microcontroller Microcontroller LCD Screen LCD Screen Wireless Chips Wireless Chips 9

10. Temperature and Pressure Temperature sensor (0-300 degrees Fahrenheit) x 2 Temperature sensor (0-300 degrees Fahrenheit) x 2 Pressure sensor Pressure sensor (0-100 psi) x 1 Requires supply voltage (12V) Requires supply voltage (12V) Outputs current Outputs current (4-20mA) (4-20mA) 10

11. Sensor Measurement Circuit From datasheet: Z Lmax= (Vs-9.6)*50 From datasheet: Z Lmax= (Vs-9.6)*50 Vs=12V from car battery, Vs=12V from car battery, ZLmax =120 ohms Issue: at 20mA, A/D voltage will be only 2.4V Issue: at 20mA, A/D voltage will be only 2.4V Solution: Adjust A/D resolution (0-2.56V) Solution: Adjust A/D resolution (0-2.56V) 11

12. A/D Method - Temperature A/D Res (2.56/255) Volts Sensor Output (mA)uC Bit NumberTemperature (Fahrenheit) 0.484.00480.00 0.494.08491.56 0.54.17503.13 0.514.25514.69 0.524.33526.25 0.534.42537.81 0.544.50549.38 2.3419.50234290.63 2.3519.58235292.19 2.3619.67236293.75 2.3719.75237295.31 2.3819.83238296.88 2.3919.92239298.44 2.420.00240300.00 12

13. Linear Based Method Temp=(1.5625*A/D Value)-75 Temp=(1.5625*A/D Value)-75 Attempt 1: Temp=((A/D Value*3)/2)-75 Attempt 1: Temp=((A/D Value*3)/2)-75 Attempt 2: Temp=((A/D Value*1563)/1000)-75 Attempt 2: Temp=((A/D Value*1563)/1000)-75 Solution: Look up table, use memory available Solution: Look up table, use memory available 13

14. A/D Method - Pressure A/D Res (2.56/255) Volts Sensor Output (mA) uC Bit NumberPressure (PSI) 0.484.00480.00 0.494.08490.52 0.54.17501.04 0.514.25511.56 0.524.33522.08 0.534.42532.60 0.544.50543.12 2.3419.5023496.87 2.3519.5823597.40 2.3619.6723697.92 2.3719.7523798.44 2.3819.8323898.96 2.3919.9223999.48 2.420.00240100.00 14

15. Linear Based Method Temp=(0.5208*A/D Value)-25 Temp=(0.5208*A/D Value)-25 Attempt 1: Temp=(A/D Value/2)-75 Attempt 1: Temp=(A/D Value/2)-75 Solution: Look up table, use memory available Solution: Look up table, use memory available 15

16. Engine RPM Measurement ACI Hall-effect current sensor ACI Hall-effect current sensor TTL output TTL output Induced supply power Induced supply power Meets amperage range Meets amperage range 16

17. Overview Summary Summary Measurement Strategies Measurement Strategies LabVIEW User Interface LabVIEW User Interface Microcontroller Microcontroller LCD Screen LCD Screen Wireless Chips Wireless Chips 17

18. LabVIEW Interfacing: Front Panel 18

19. LabVIEW Interfacing: Front Panel 19

20. LabVIEW Interfacing: Front Panel (cont.) RS232 communication protocol RS232 communication protocol Complete control over settings Complete control over settings Data logging feature Data logging feature 20

21. LabVIEW Interfacing: Front Panel (cont.) 21

22. LabVIEW Interfacing: Front Panel (cont.) Pressure and temperature updated in real time along with engine RPM and speed Pressure and temperature updated in real time along with engine RPM and speed Warning lights indicate dangerous levels Warning lights indicate dangerous levels 22

23. LabVIEW Interfacing: Front Panel (cont.) 23

24. Data vs time displays operate independently Data vs time displays operate independently LabVIEW Interfacing: Front Panel (cont.) 24

25. LabVIEW Interfacing: Parallel Computing 25

26. Overview Summary Summary Sensors Sensors LabVIEW User Interface LabVIEW User Interface Microcontroller Microcontroller LCD Screen LCD Screen Wireless Chips Wireless Chips 26

27. Microcontroller: Amtel ATmega 128 MCU 16 MHz clock 16 MHz clock 8 A/D converters 8 A/D converters Voltage regulator (5.5-15V) Voltage regulator (5.5-15V) Dual UARTS Dual UARTS Additional power and ground connectors Additional power and ground connectors 27

28. Programming Phases A/D Converter A/D Converter RS-232 Interface RS-232 Interface RPM Counter RPM Counter Touchscreen Touchscreen All Together All Together 28

29. Programming Phases A/D Converter A/D Converter RS-232 Interface RS-232 Interface RPM Counter RPM Counter Touchscreen Touchscreen All Together All Together 29

30. A/D Conversion Records oil pressure, oil temperature, and coolant temperature Records oil pressure, oil temperature, and coolant temperature A/D inputs: 0-2.56V A/D inputs: 0-2.56V Sensor voltages: 0.48-2.4V Sensor voltages: 0.48-2.4V Scaled into single byte value Scaled into single byte value 30

31. A/D Conversion ADC clock machine cycle: 8us ADC clock machine cycle: 8us 1 st conversion: 200us 1 st conversion: 200us Normal conversions: 104us Normal conversions: 104us Three conversions: 312us Three conversions: 312us Vref = 2.56 V Vref = 2.56 V 31

32. Programming Phases A/D converter A/D converter RS-232 Interface RS-232 Interface RPM Counter RPM Counter Touchscreen Touchscreen All Together All Together 32

33. RS-232 Interfacing Previous experience with transmit/receive Previous experience with transmit/receive Stair step progress: Stair step progress: Polling Polling Interrupt driven Interrupt driven Timer based Timer based 33

34. RS-232 Interfacing Hyper Terminal problems Hyper Terminal problems Incorrect Hyper Terminal settings Incorrect Hyper Terminal settings ASCII Setup – echo typed characters locally ASCII Setup – echo typed characters locally Transmitting/Receiving settings: Transmitting/Receiving settings: 9600 baud 9600 baud 8 data bits 8 data bits 1 stop bit 1 stop bit 34

35. Example RS-232 Communication Receive key press from computer Receive key press from computer ASCII F sent back to computer ASCII F sent back to computer Hyper Terminal displays appropriate values Hyper Terminal displays appropriate values 35

36. Example RS-232 Communication String based communication with timer String based communication with timer Sends 1abcde every 5 seconds Sends 1abcde every 5 seconds Practical application Practical application 36

37. Programming Phases A/D Converter A/D Converter RS-232 Interface RS-232 Interface RPM Counter RPM Counter Touchscreen Touchscreen All Together All Together 37

38. RPM Counter Example simulation Example simulation Set up basic pulse counting program Set up basic pulse counting program 100ms (10 Hz) sampling period 100ms (10 Hz) sampling period Counts rising edges Counts rising edges 30 Hz Pulse Input 38

39. RPM Counter Problems with 16-bit counter Had to use external interrupts Rising edge triggers interrupt Counter increments Inefficient 39

40. Programming Phases A/D Converter A/D Converter RS-232 Interface RS-232 Interface RPM Counter RPM Counter Touchscreen Touchscreen All Together All Together 40

41. Touchscreen ASCII protocol ASCII protocol CRC protocol CRC protocol Used XON/XOFF to simplify Used XON/XOFF to simplify 41

42. XON/XOFF Communication 42

43. ASCII Protocol Set byte variable 1 to 0xFE Set byte variable 1 to 0xFE Set IR word variable 0 to 0x02C9 Set IR word variable 0 to 0x02C9Opcode Internal RAM address Internal RAM value 0xD50x300x310x460x45 01FE 0xD60x300x300x300x320x430x390002C9 43

44. Jump to Page Function Does not use the normal ASCII protocol Does not use the normal ASCII protocol Reads in hexadecimal format Reads in hexadecimal format Jump to page 0x103: Jump to page 0x103: 0xA00x020x010x030x5A Command Page # MSB Page # LSB checksum Opcode Internal RAM address Internal RAM value 44

45. Calculating the Checksum Value X=0xA0+0x02+0x01+0x03=0xA6 X=0xA0+0x02+0x01+0x03=0xA6 The sums of the LSB must be 0xNN00 The sums of the LSB must be 0xNN00 0x100-0xA6=0x5A 0x100-0xA6=0x5A 0xA00x020x010x030x5A Command Page # MSB Page # LSB checksum 45

46. Programming Phases A/D Converter A/D Converter RS-232 Interface RS-232 Interface RPM Counter RPM Counter Touchscreen Touchscreen All Together All Together 46

47. All Together 47

48. Software Flowchart 48

49. Overview Summary Summary Sensors Sensors LabVIEW User Interface LabVIEW User Interface Microcontroller Microcontroller LCD Screen LCD Screen Wireless Chips Wireless Chips 49

50. Touchscreen Amulet Technologies Amulet Technologies GEMStudio GEMStudio µHTML µHTML 9600 Baud 9600 Baud Resistive technology Resistive technology LCD GUI from 2010 Project 50

51. Touchscreen Design Design Numerical displays Numerical displays Warning indicators Warning indicators Inter-widget communication Inter-widget communication Multiple pages Multiple pages 51

52. Touchscreen Design 52

53. Touchscreen Widgets Widgets Function Buttons Function Buttons Calls a function when hit Calls a function when hit Numeric Fields Numeric Fields Pulls the values from bytes in the Amulets internal RAM Pulls the values from bytes in the Amulets internal RAM 53

54. Touchscreen Communications with microcontroller Communications with microcontroller ASCII protocol ASCII protocol CRC protocol CRC protocol Amulet as slave Amulet as slave XON/XOFF protocol XON/XOFF protocol 54

55. Overview Summary Summary Sensors Sensors LabVIEW LabVIEW Microcontroller Microcontroller LCD Screen LCD Screen Wireless Chips Wireless Chips 55

56. Wireless Chips Chipcon CE2500M Chipcon CE2500M Voltage Regulator Voltage Regulator RS-232 RS-232 Packets Packets Infinite transmission Infinite transmission 56

57. Wireless Chips 57

58. Aerocomm AC4790 58

59. Aerocomm Software 59

60. Future Work Noise suppression circuitry Noise suppression circuitry Enclosures Enclosures Sampling rates Temperature, RPM, land speed Land speed calculation Support documentation Support documentation 60

61. Schedule Week of:CalebPhilGeorge 12/5/2010finalize parts list with mechanical engineers winter breakorder parts, research 1/23/2011program temperature sensorresearch touchscreen software design interface for LabVIEW setup 1/30/2011program pressure sensorwork on example programs program LabVIEW for receiving data 2/6/2011program wheel speed sensor work on design options for touchscreen GUI test LabVIEW for receiving data 2/13/2011program displacement sensordesign GUI for touch screenwork on sensor circuitry 2/20/2011program and combine modulesdesign GUI for touch screenmake sensor test bench 2/27/2011program and combine modules finalize design and construct GUI make sensor test bench 3/6/2011 set up analog to digital converters work on communications with microcontroller work on LabVIEW datalogging 3/13/2011spring break 3/20/2011implement counters finalize GUI / communications with microcontroller work on LabVIEW datalogging 3/27/2011 program microcontroller to transmit data to LabVIEW finish all touchscreen elements. start on wireless finalize LabVIEW design and sensor circuitry 4/3/2011interface all devices together. work on wireless devices 4/10/2011interface all devices together. work on wireless devices 4/17/2011work on wireless devices. documentation/finalization/final report/presentation 4/24/2011 documentation/finalization/final report/presentation 5/1/2011 61

62. Questions ? 62

63. Calculating Timer Value for Pulse Counter 63