The Infrared Receiver is used to receive infrared signals (which is used for remote control detection). There is a IR detector on the Infrared Receiver which is used to receive the infrared light emitted by the Infrared Emitter / Source. This IR detector contains a demodulator inside that looks for modulated IR at 38 KHz. The Infrared Receiver can receive signals well within 10 meters. If the distance is more than 10 meters, the receiver may not get the signals or might even receive weak signals. We often use the two - the Infrared Receiver and the Infrared Emitter to work together.