Sasha is a FIRST FRC competition robot that was converted over to a Raspberry Pi based control system. Sasha was initially designed to throw frisbees and later had pneumatic T-shirt cannons added. The original Texas Instruments Jaguar motor controllers and some Spike relays drive motors and solenoids. A Pololu Maestro servo controller sends PWM signals to the motor controllers. A custom Pi Hat runs the Spike relays and interfaces with limit switches, and a XBox 360 controller is used for driving, aiming and shooting. See these repositiories for more details into the hardware and associated Python classes.
Setting up a Raspberry Pi based bot is actually quite simple. Check out PiBot for details on getting started.