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ECE 477 Design Review Team 14  Spring 2006

ECE 477 Design Review Team 14  Spring 2006. Jason, Nathanael, David, David. Project Overview. Driver interface for Solar Racing Team Communication with onboard power trackers and telemetry board via CAN bus Display speed, battery power, and other information on the LCD

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ECE 477 Design Review Team 14  Spring 2006

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  1. ECE 477 Design Review Team 14  Spring 2006 Jason, Nathanael, David, David

  2. Project Overview • Driver interface for Solar Racing Team • Communication with onboard power trackers and telemetry board via CAN bus • Display speed, battery power, and other information on the LCD • Allow driver to navigate through a text-based interface to customize display information and issue commands to the power trackers

  3. Project-Specific Success Criteria • An ability to display vehicle status information on an LCD. • An ability to navigate display menus and make selections using an RPG. • An ability to perform LCD backlight power management (e.g., turn the backlight on for X seconds after the RPG is turned/pressed). • An ability to obtain vehicle diagnostic information via the CAN bus. • An ability to switch to “debug” mode (when a RS-232 cable is connected) in which a diagnostic menu is displayed.

  4. Block Diagram

  5. Professional Components • Constraint analysis and component selection rationale • Patent liability analysis • Reliability and safety analysis • Ethical and environmental impact analysis

  6. Constraint Analysis

  7. Component Selection Rationale • Design constraints • Microcontroller • PIC18 family • Support CAN standard • Large Flash & SRAM (CANopen library) • 29 I/O Pins • Power supply • Step down from 12 VDC to 5 VDC • 400mA @ 12 VDC input current limit • High efficiency to reduce power-loss

  8. Component Selection Rationale • Microcontroller (PIC18F series with CAN, I2C, UART, PWM) • PIC18F4680 (44pin TQFP) Cost: $6.08 *** • 64Kb Flash • 36 I/O • PIC18F2680 (28pin SOIC) Cost: $5.54 • 25 I/O (not quite enough need 29) • Could use larger/different PLD to expand I/O, but PLD cost increase is greater than $0.54

  9. Component Selection Rationale • Power Supply (~400mA @ 5VDC) • MAX744A • 750mA output at 5VDC • 6 external components • ~88% efficient, 400mA @ 5VDC • Needs special layout with copper pours • LTC1174-5 *** • 640mA output at 5VDC • 6 external components • ~90% efficient, 400mA @ 5VDC • Recommended in class documentation

  10. Patent Liability Analysis • Overview • Three Patent were found to be similar • Literal infringement • Infringement under doctrine of equivalent • Action Recommended

  11. Search Result #1 • Information display system for a vehicle • Patent Number : 5,006,829 • Assignee: Honda. Giken Kogyo K.K. • Year: 1988 • Description: • Sensors • A pair of buttons are used for sequentially shifting the menu item • After a certain time interval, go to idle mode

  12. Search Result #2 • Display apparatus for vehicle • Patent Number : 5,121,112 • Assignee: Nissan Motor Company • Year: 1989 • Description: • Sensors • Message is assigned a degree of priority level • Indicator for alert message

  13. Search Result #3 • Information display appatatus for vehicle • Patent Number : 5,764,139 • Assignee: Toyota Jidosha Kabushiki Kaisha • Year: 1996 • Description: • Sensors, detecting running condition • Status are stored in local memory • Size of Speed increase when vehicle is going straight

  14. Literal infringement • Violating Condition • Ever claim must match • Potential infringement Patent • Information display system for a vehicle

  15. Infringement under doctrine of equivalent • Not as trivial to be identified • To determine what function is substantially the same • To locate the differences

  16. Action Recommended

  17. Reliability/Safety Analysis

  18. Ethical/Environmental Analysis

  19. Ethical/Environmental Analysis • Ethical Analysis • Focus on the safety of the driver from Hardware, Software, and System Perspectives. • Hardware • High Efficiency DC/DC converter was chosen for its high efficiency and short circuit protection. • Optical Isolators was installed to protect the microcontroller and LCD from Damage. • PCB was carefully designed to avoid overheating and short circuit problems.

  20. Ethical/Environmental Analysis • Software • Setting the CAN communication interrupts at the highest priority to display the most accurate and timely information. • System • Surface mount components were used on PCB • Connectors have board-retention devices. • LCD and PCB were tightly mounted in a plastic enclosure.

  21. Ethical/Environmental Analysis • Environmental Analysis • Product Manufacture • Plastic enclosures made of non-biodegradable plastic • Numbers of hazardous by-products are produced during the PCB manufacturing cycle. • Normal Use • Car runs on solar energy, no significant impact. • Disposal/Recycling

  22. Ethical/Environmental Analysis • Environmental Analysis • Disposal/Recycling • The plastic enclosure, which is not biodegradable, should be recycled. • PCB, which contains hazardous chemicals and metals, should be disposed of properly. • Encourage to recycle the entire system as a whole.

  23. Design Components • Packaging design considerations • Schematic design considerations • PCB layout design considerations • Software design considerations

  24. Packaging Design

  25. Schematic Design • Power Supply Design (page 3)

  26. Schematic Design • Microcontroller Block (page 2)

  27. Schematic Design • PLD/LCD Block (SPI and I2C) (Page 2)

  28. Schematic Design • CAN Communications (page 3)

  29. Schematic Design • RS232 Communications (page 3)

  30. Schematic Design • Button Interface (page 1)

  31. Schematic Design • Optoisolators (page 1)

  32. Schematic Design • LEDs (page 1)

  33. Schematic Design • Analog and Buzzer (page 1)

  34. PCB layout design Consideration • Trace Size • POWER / GND: 40 mils traces • Signal: 12 mils traces • Minimum space between two traces = 8 mils • Component Placement • Analog components must be separated from Digital components to avoid digital noise coupling • Active components are placed on Top layer and Passive are placed on Bottom layer. • Right Angle connectors are hanging over the boundary for easier accessibility.

  35. PCB layout design Consideration • Component Placement • Mounting holes located at 1.375 inches from the center of the board. • Components within each functional block should be closed to each other to minimize trace length. • The boarder of some footprints should use insertion outline to avoid placement errors.

  36. Final PCB layout 1.375 inch

  37. Initial PCB • Component Placement • Mounting holes located at 1.375 inches from the center of the board. • Components within each functional block should be closed to each other to minimize trace length. • The boarder of some footprints should use insertion outline to avoid placement errors.

  38. Final PCB Please include final PCB picture here if available.

  39. Software Design

  40. Success Criteria Demonstrations • An ability to display vehicle status information on an LCD. • An ability to navigate display menus and make selections using an RPG. • An ability to perform LCD backlight power management • An ability to obtain vehicle diagnostic information via the CAN bus. • An ability to switch to “debug” mode (when a RS-232 cable is connected) in which a diagnostic menu is displayed. PSSC Demo Video

  41. Individual Contributions • Team Leader – (Jason)Yuk Hang Chan • Team Member 2 – Nathanael Huffman • Team Member 3 – (David) Wei Zhou • Team Member 4 – David Sung

  42. Team Leader – Yuk Hang Chan • System menu design • Menu tree • Navigated by RGP buttons • Debug menu design • Serial cable detect • Menu control • Idle page display (Speed, Bar graph) • Configuration of RPG buttons

  43. Member 2 – Nathanael Huffman • Hardware Design • Schematic • PCB • Hardware Assembly • Hardware Debugging • Packaging • Cable Harnesses

  44. Member 3 – David Wei Zhou • Initialization Of All Peripherals • Timer • Interrupt • A/D channel (sensors) • CAN bus communication • Sending CAN message (polling base) • Receiving CAN message (Interrupt base) • Debug Menu Data display

  45. Member 3 – Yuan-Jiun Sung • Completion of PCB design and layout • Completion of Senior Design Report and User Manual • Checking the Ethical/Environmental designs of our project • Involved in initial component selection and finding datasheet for each component

  46. Project Summary • Important lessons learned • Contribution to Purdue Solar team • Inter-team • Cooperate with two other teams • Developed CAN protocol • Developed interface specifications • Intra-team • Hardware vs. Software (communication) • Keep motivated • Start software early! • Should prepare timeline in early design stage

  47. Project Summary • Version 2 changes • Enhance menu system expandability • CAN cable detection • Device won’t function without CAN cable connected • Dedicated CAN buffer to ensure ability to handle busy traffic • Bigger PLD • Solar Team will continue on the project

  48. Questions / Discussion

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