Optical joystick using a plurality of multiplexed photoemitters and a

Abstract

An electro-optical input device for computers or electronic games which uses electro-optical elements to sense input from a user. A user actuation element, such as a directional control pad or a joystick is pivotally disposed on a printed circuit board. Two photoemitters are mounted on the printed circuit board, at or near the circumference of the footprint described by the user actuation element. The photoemitters are positioned 90.degree. apart, one along the North-South axis of flit of the actuation element, and one along the East-West axis. At least one photodetector is mounted to the base at or near the pivot point of the actuation element so that it can receive light from both of the photoemitters. A skirt or flange depends annularly from the actuation element, at or near its periphery, positioned between the photodetector and the photoemitters. As a user applies a force to one side of the actuation element, the annular flange will be displaced and act as a light shutter, either blocking the light from the photoemitters or allowing the photodetector to receive a greater amount of light. By comparing the amount of light received from each of the North and West photoemitters when a force is applied, to the amount of light normally received from these photoemitters when the actuation element is in its neutral position, the input device is able to determine both the direction and magnitude of the force applied by the user.