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Preliminary Design Review 30 January 2007

Preliminary Design Review 30 January 2007. Black Box Car System (BBCS) ctrl + z: Benjamin Baker, Lisa Furnish, Chris Klepac, Benjamin Mauser, Zachary Miers. Motivation. Car accidents Provide proof of who was at fault Provide information about force of crash Other traffic incidents

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Preliminary Design Review 30 January 2007

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  1. Preliminary Design Review30 January 2007 Black Box Car System (BBCS) ctrl + z: Benjamin Baker, Lisa Furnish, Chris Klepac, Benjamin Mauser, Zachary Miers

  2. Motivation • Car accidents • Provide proof of who was at fault • Provide information about force of crash • Other traffic incidents • Capture information about what really occurred if ticketed for speeding, following, etc.

  3. Concept of Operations:Goals • Provide visual information of car’s surroundings for period of time before accident • Use accelerometer to determine if accident has occurred • If programmed acceleration level occurs, BBCS knows a crash has occurred • Force reading will be saved in conjunction with visual data • Removable storage • Crash video can be viewed on home computer • Autonomous • In event of accident, data automatically saved • Powered by vehicle

  4. CONOPS:Requirements Performance Requirements

  5. Block Diagram: Main Camera Accelerometer Black Box User interface Reset Storage

  6. Block Diagram:Black Box Power Reset LED Main Processor or IC LCD IC Computer Flash Camera Storage Accelerometer IC RAM Camera

  7. Implementation:Microcontroller • Flash-based, 16/32-bit • ARM • Microchip PIC • MSP430 • Re-programmable • On-board ADC, UART, I²C, Timer/counter • Interface to sensors, Flash data log • USB 1.0/2.0 capable

  8. Implementation:Microcontroller • One main processor to act as a central processor to control all coprocessors • Video processors, memory, accelerometer, etc. • Our design will use one processor for each camera module • This will allow us to more easily implement several video sources if extended

  9. Implementation:Video • We’re looking to use either a CCD or CMOS camera as our video sensor. • Ideally we would like to use a camera with USB output and onboard compression. • Using a webcam oriented device, we’re hoping to eliminate any need to program USB drivers. With a corresponding USB microcontroller, this might be possible.

  10. Implementation:Video • Camera – STVS6522 • Advantages • Only needs a 5V supply • Large range on input voltage (4.1-5.6) • Adjustable Frame Rate • Black and White or Color images • USB 2.0 compliant • Field of depth is infinite with a fixed focus

  11. Implementation:Video • Disadvantages • Operating range isn’t ideal for a full automotive design (32-104 F °) • Minimum focus is 20 cm (~8 in)

  12. Implementation:Video Compression We assume we are getting raw video from an un-compressed CMOS camera Estimated needs: • Moving JPEG conversion • Real time video compression (at least fast enough to convert the first frame by the time the second frame is taken)

  13. Implementation:Video Compression

  14. Implementation:Video Compression • Video Conversion Types • Digital Camera Coprocessor • IC Programmed to do video compression • Ideal Setup: • CMOS Digital Camera coprocessor for digital still and web cameras • Real time video conversion with 50:1 compression ratio • I2C or USB data output

  15. Implementation:Video Compression • Suppliers: • STMicroelectronics • Motorola • BeyondLogic • Digi-Key

  16. Implementation:Memory • Fast re-writeable memory to buffer image data. • SRAM • Advantages • Programming simplicity • Control simplicity • Disadvantages • Expensive • Limited size • Requirements • Capable of handling 5 frames/sec video input • Low power consumption

  17. Implementation:Memory • Slow large capacity memory for image data storage • Flash • Advantages • Robust • Cheap • Disadvantages • Slow access speed • Requirements • Compact Flash interface

  18. Implementation:Communication • Ideal Solution • I2C • USB 2.0 / 1.0 • Fallback • Several I/O ports

  19. Implementation:Accelerometer • We’re looking at using a MEMS based accelerometer to detect a crash. • The accelerometer is the central trigger for the system. • The entire black box is in a looping state until the accelerometer interrupts and sets the system into its crash procedure.

  20. Implementation:Accelerometer • Accelerometer - LIS3LV02DQ • Advantages • 3 axes (crash from above?) • I2C/SPI output interfaces directly with Microcontroller • Factory calibrated with offsets loaded on startup • Variable sampling frequency

  21. Implementation:Accelerometer • Disadvantages • 2.5 V operation (increasing complexity with power supply) • Configurable to +/- 2 or 6 gs • Might trigger too easily

  22. Implementation:Power We assume we are getting power from a car battery that varies from 8-16V. • Estimated needs: • One 12V-1A converter for cameras and sensors • One 5V-5A and a 3.3V-5A converter for processors, memory, and other circuitry

  23. Implementation:Power

  24. Implementation:Power • Supply Types Available: • Linear Voltage Regulators • Switching Converters • Ideal Setup: • 12V-1A, buck-boost • 5V-5A, buck • 3.3V-5A, buck

  25. Implementation:Power • Designing the Supply • Hard way: Design it by hand, go through plenty of equations, and have a less efficient converter than one you can buy for cheap. • Easy way: Go to National Semiconductor, go to the Power Webench, type in your input voltage and your output voltage and current and it designs it for you.

  26. Implementation:Power • The result for a 12V-1A Supply:

  27. Implementation:Power • Suppliers: • National Semiconductor • Texas Instruments • STMicroelectronics • Analog Devices • Many, many others

  28. Implementation:User Interface • Ideal Solution • Plug into computer and all video sources show up and start to run • On-station displays (LCD or LED on box) • Fallback • Data display in Windows Application (Excel, Visual Basic, etc.) • Data dump to HyperTerminal convert video using program then view video sources

  29. Implementation:Enclosure • Ideal Solution • Custom Plexiglas enclosure • Weatherproof • Transparent (for Expo) • Strong and Shock resistant (protect equipment in the event of collision) • Fallback Solution • Generic electronics enclosure • Locking metal box • Some foam to lessen shock

  30. Contingency Plan • No video altogether • Instead, base system around inputs of speed, acceleration, braking, blinkers, lights, etc. directly from car

  31. Extensions • Other sensors • Speed • Lights, blinkers, brakes • GPS • Four video sources instead of one • 25fps, 30 second video loop

  32. Testing • Skateboard with system attached to it • Push skateboard into wall (collision) • Kick skateboard (side collision) • Drop basketball on top of car (falling rocks) • Hold bacon behind car (Cop with false ticket)

  33. Division of Labor • Video: Chris Klepac • Compression: Zach Miers • Power: Ben Baker • Accelerometer: Chris Klepac • Microcontroller and misc. sensors: Lisa Furnish & Zach Miers • Enclosure: Ben Mauser • User Interface: Ben Mauser • Documentation: All • PCB Design: Chris Klepac & Ben Mauser

  34. Schedule

  35. Questions ?

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