Designers of devices that implement IR proximity detection need to be concerned with several items. First and foremost the detection range must be determined. In order to detect the reflected energy, the object must be within range of the IR energy source. When determining the proximity range the IR energy output must be set in order to accommodate the decrease in light which is proportional to the inverse square of the distance. Taking into account that the light must travel in the transmit and receive path, the energy that the detector sees is inversely proportional to the fourth power of the distance from the emitter.