A computer game system uses an infrared sensor which produces an infrared light to produce pulse of infrared light. Optics focus reflections from the infrared light pulse from different portions of the environment to different detectors in a 2D array of detectors. The detectors produce indications of the distance of the closest objects. The indications can be used by a processor to determine each action. The determined action can be used as input to a computer game. The infrared sensor can also be used with a musical keyboard system.