Both the motor and the encoder are connected to an Arduino Pro Mini which receives step and direction commands from the printer controller.

An Arduino is a popular open-source single-board microcontroller. Learn how to program one and let the possibilities take shape.

You could simply program your machine to give a visual indication of whether it's a lie or the truth by programming your Arduino to detect large shifts in your electrodermal activity.

An Arduino Pro mini handles the selection between outputs by driving a selection of relays with appropriate timing.