A position sensing controller, sometimes referred to as "controller" includes a novel optical gate that is located adjacent to a light source and to a light sensor. The optical gate changes the amount of light incident on the light sensor in response to a change in position of a movable element in the controller. In response to the incident light, the light sensor drives a position signal on an output terminal, which position signal approximately indicates the position of the movable element. The position signal can drive any electrically controllable device, such as a game machine, a personal computer and an interactive television set top. The use of optical principles in a position sensing controller allows various optical position sensing parts of the controller, such as the light source, the light sensor, and the optical gate to be physically separated from each other and so avoid the mechanical wear and tear caused by friction in conventional controllers.