Communications within the car

Hello everyone, I am Jens Matthys and I am responsible for the CAN system and some low voltage electronics in this years car. In this post and the following posts I will describe a few important electronic systems that will be present in the final build of our car.

Firstly we will discuss the CAN system, short for Controller Area Network. In a (electrical) car there are a lot of different electrical/electronical systems with different functions. These systems include lights, dashboard, motor controllers, pedalbox and different kinds of sensors to measure speed, rpm, temperature and more.
All these systems need to communicate with a main controller (first picture) that keeps track of all this data. Some systems will also communicate with each other. For example : when you press the throttle, the motor controllers need to know how fast the motor has to spin.

If all these systems would be wired like normal, there would be a lot of different wires going everywhere. That’s why the CAN protocol is used in cars. All systems are connected with two wires to the CAN-bus and all messages are labeled with an address based on their priority. This way systems are able to listen to the CAN bus and when they see a relevant address, they can read the corresponding message.

Our main controller is based on the Teensy 3.5 microcontroller. This controller will log all the information on a SD-card so our team can analyze it afterwards. The PCB also has some connectors to connect a 4G module. This would allow us to send the data to a webserver or to a computer program where we can view the data in real-time. The Teensy 3.5 is equipped with a real-time-clock which keeps track of the time even when the car is not powered.

The first PCB’s are designed and are ready to be send out to our sponsor Eurocircuits. They will fabricate the PCB’s and send them back to us. When we receive the PCB’s, we can start to assemble and program them.

Some of the other PCB’s which will be send to Eurocircuits are the dashboard, BSPD and RTDS but these will be discussed in another post.