IR LED is an infra red ray emitter. IR LED is also called as IR Transmitter. IR LED emitter the Wave in the wavelength range of 490 to 649 Nano meter.The usage of IR LED is LED like normal LED. The LED is bigness or strength of IR light is controlled by limiting the current through it. Generally a 100 to 330Ω range of resistor is connected with +5v power supply. Since the IR becomes are directional it can be used channel obstacle sensor or line follower circuit. This IR LED is used with photo diode or photo transistor as receiver circuit. In some cases even LDR also can be used with IR LED.