The project is moving along quite well.
Today I received my second order from VEX Robotics and got a chance to finish the chassis.
Here are some photos:
I now need to get a power source for the four motors. I’m thinking of getting a couple of lead-acid batteries at 12V and reduce the voltage output to 9V.
I’m thinking not to use the VEX motor controllers and to use an H-Bridge for each motor (I already have one of these chips). The advantage of this approach is that I can drive each motor with 2 digital outputs directly from the RPi, rather than putting an arduino in the middle. By the way, the H-bridge I linked above allows the use of two motors per pcb, but things will run better if each chip is used in “single motor” mode (more amps available per motor).