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Project Forget-Me-Not. TCSP2 - Design Constraints ECE477 Group 4 Chris Cadwallader Craig Pilcher Andy sydelko Mike williams. Updated PSSCs. An ability to determine the operating state of the vehicle via the OBD-II port. An ability to determine the presence of a child in a safety seat.
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Project Forget-Me-Not TCSP2 - Design Constraints ECE477 Group 4 Chris Cadwallader Craig Pilcher Andy sydelko Mike williams
Updated PSSCs • An ability to determine the operating state of the vehicle via the OBD-II port. • An ability to determine the presence of a child in a safety seat. • An ability to use multiple safety seats in one vehicle. • An ability to sound an audible alarm when the ignition is turned off. • An ability to interface directly to the internal vehicle CAN.
Important Design Constraints • On-chip peripherals • CAN, PWM for audio output • On-chip memory • Flash for audio samples • Power consumption • Child-side is battery powered • Cost • Off-chip peripherals • RF Tx/Rx, 433 MHz
Microcontroller – 9S12DP512C • Advantages • Multiple OBD-II protocols supported • CAN, SWCAN, Keyword 2000, J1850 • PWM, A/D for older protocols • Built-in software libraries (Code Warrior) • 512K Flash • 2 SCI ports (debugging and RF decoder) • Extra input pins for future expansion • 8 inputs = 256 possible status messages • Disadvantages • Audio – Want to be loud enough to hear easily • LM386 Audio Amplifier
Wireless Interface • RF • Adequate range • Low power consumption • Low cost • Linx XCVR • Tx and Rx units easily paired • No micro needed on Tx side – lowers power cost • RFID • Passive transmitters – low range • Active transmitters – disposed after use • Prohibitively expensive