project forget-me-not

TCSP2 - DESIGN CONSTRAINTS

ECE477 GROUP 4

CHRIS CADWALLADERCRAIG PILCHERANDY SYDELKOMIKE WILLIAMS

Project Forget-Me-Not

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.

Block Diagrams

Block Diagrams

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

CostOff-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