Gertboard is the ideal add-on for Raspberry Pi. Designed by Gert van Loo, it is a flexible experimenter board that plugs directly into your Raspberry Pi, and out into the physical world, allowing you to detect and respond to external physical events. Detect and output analogue voltages. Drive powerful motors. Detect switch presses. Illuminate LEDs and drive relays. Jumper cables allow you to hook up different parts of the circuit in many different ways, allowing total flexibility. All controlled by your own Raspberry Pi.