Two Norweigian technology enthusiasts and artists have created a step-matrix sequencer that is controlled via chess pieces and an Arduino Mega-style board. A chess board is fitted with reed switches under every position, and they are activated by magnets buried inside chess pieces. The reed switches are then monitored via the Arduino Mega, and other parameters are controlled by a customised control box. See it in action below:
Although this would seem to be rather complex, it could be recreated in a day or two. To get started, find the complete instructions and code here. You'll need an Arduino-compatible board with plenty of I/O - which means our Freetronics EtherMega - the fully Arduino Mega2560-compatible board that also includes a microSD socket and Ethernet:
