Change: Interface PCB

Dev Kit PCB installed on a Pi 2.

Background

A Printed Circuit Board (PCB) has been designed and manufactured. The goals were to

1. make it quicker and easier to build a system and to make it more reliable,
2. to establish a relationship with a board house and
3. to test the footprint of the RJ connectors and mating with the Pi
4. to select an opensource pcb layout package and learn how to use it.

This is an interim solution - a step towards the goal of a complete turnkey system.

• All sensor plug in.
• 12 VDC power supply with battery voltage monitoring

Problems

1. ADC is only one channel.
2. No Real Time Clock (RTC).
3. Board does not meet Pi HAT specification.
4. Board is not general purpose but limited to our use.

Proposed change

Split this board in two, Board A and Board B.

• Board A will be a general purpose interface board that meets the Pi HAT specifications and contains:

1. at least one 4 channel ADC so each load cell will be individually measured instead of being summed.
2. Real Time Clock with battery backup.
3. Configuration ROM
4. Power supply

• Board B will have all the connectors installed in a bulkhead configuration. It will connect to Board A by directly plugging into a header on Board A or connect via a ribbon cable.