1. In a computer-controllable robotic device using a multipurpose microcomputer including an output port having several discrete input and output contacts, such microcomputer having programming modifiable to control the computer to provide a high or low voltage output signal to a selected single output contact of such port, and a robot having a plurality of different electrically-powered actions, the improvement comprising an interface operably connectable between such microcomputer port and such robot and including power-controlling means for receiving the output signal from such selected single output contact of the microcomputer port and for supplying electric power to the robot for effecting various different selected electrically-powered actions of the robot as determined by the programming of the microcomputer without reference to or being affected by the voltage at any other output contact of the microcomputer output port.