US Patent 6931231 Infrared generator from audio signal source

An apparatus and method for converting an audio signal output through a stereo headphone jack into an infrared remote control signal. The invention utilizes the audio output to generate positive and negative pulses for operating two infrared light emitting diodes placed in parallel with opposite polarities. This allows for multiple devices with audio output jacks to be utilized as remote control devices. This connection also allows for doubling of the audio output frequency to generate infrared signals at frequencies above the normal capabilities of the audio output.