This demonstration uses Scratch GPIO developed by Simon Walters at Cymplecy. The robot can be purchased for about £25 – £30 such as through Rapid. It’s not too difficult to build – but you need to keep the wires separate so you can wire them up.
5 motors needs 15 GPIO pins. Each motor needs 2 motor direction controls and a power control. I wired them up to some H bridges and connected them to the Pi. Scratch GPIO can give a lot of outputs.
Once connected, it’s a simple case of altering motor directions and turning power on and off. With time, you could program complex manouvres.