Abstract: A potentiometer includes a shaft, a base including a printed circuit board on which are fixedly mounted a light emitter and a light receiver arranged opposite to and spaced from the light emitter, the light emitter being supplied with steady voltage to emit light and provide working voltage to the light receiver, a circular seat formed with an opening and fixedly mounted on an upper end of the shaft, a plastic film arranged on an outer edge of the opening and disposed between the light emitter and the light receiver, the plastic film being provided two end portions which are opaque and an intermediate portion which decreases in transparency from one side to another side thereof, and a cover fixedly mounted on the base to enclose the circular seat, whereby the potentiometer is of high sensitivity, durable in use, low in cost, easily converted from a conventional rheostat and fit for mass production.

Abstract: A joystick direction control means mainly including a variable resistance, a mounting seat assembled onto a resistance adjusting rod of the variable resistance and being fixed thereto by lugs projecting from the variable resistance and engaging with four comers of the mounting seat, and a mounting board assembled to the mounting seat by extending a central shaft of the mounting seat and two retaining wings at two sides of the central shaft through a receiving hole on the mounting board and turning the mounting board about the central shaft by 90 degrees, so that the whole joystick direction control means can be quickly assembled with the mounting board properly tightened to the mounting seat.

Abstract: An optical analog rocker in which mechanical movements of a manipulated control rod of the rocker are converted into electronic signals by means of an infrared emitter and an infrared receiver. The infrared receiver shifts relative to the infrared emitter when the control rod is swayed in different directions and thereby, changes the distance between it and the infrared emitter. The changing distance causes the infrared receiver to generate light-sensitive signals of different high or low linear voltage and current. The signals are received by a game interface card and are correctly sent to a computer. With these arrangements, the disadvantages associated with a worn variable resistance contact included in a rocker, such as poor contact condition and unstable signal output can be avoided.