Sunday, October 6, 2013

Motorsports CAN bus

This year I've decided to rejoin the MIT motorsports team. The team designs, builds, and races a car for one of the various FSAE competitions held each year. I was on the team for a little over a semester my freshman year working on a temperature sensor network; it went okay. Now I'm back and the team has switched to the electric competition. My main task is to compact the motor controllers such that they actually fit inside the car. Because that's moving a bit slowly, and in the interest of rekindling the blogging habit, I have a smaller project to present first.

Modern cars have electronics and sensors stuck inside just about every functional part. These bits and bobs need to talk to the main computer and eachother to be useful. Just about every car made after 1996 (and quite a few before then) use the CAN bus protocol for communication. Our car is being made after 1996 so it's going to use CAN bus. To reduce the number of wires running all over the car there will be a breakout CAN node in the front of the car. Last Saturday I mounted and wired the connectors in a laser cut panel I made the week before. It needed to be a custom job because there were all sorts of problems from the board through holes not being big enough to a lack of keyways in the panel.

TL;DR: here are some pictures of a thing I did on Saturday. Just to be clear, I didn't make the circuit or boards for this.

"Branded" boards.

 Each connector has signal, common voltage, and common ground.

8 sets of wires down to just one.

 Lots of precision cutting and stripping.

The aluminum case will be cut down to the correct length now that we know how long the module is.

Until next time.