Atari Robokit

The Robokit is an interface for the Atari ST that plugs into the cartridge/rom port. It allows the connection of switches/sensors and various DC components (like motors, lamps and servos) which can be controlled by a host application run on the ST.

The board was designed to control Lego Technic and Fishertechnic components, however there is no reason why you could not use it to drive other devices provided they are capable of operating at 4.5 volts