An infrared transmitter is simply a Light Emitting Diode which generates IR light (invisible IR light)--light with a wavelength of between 1 mm and 750 nanometers, and some associated circuitry. In an infrared remote control, for example, pushing a button sends an electric signal to the LED, which converts the signal into a beam of infrared light. The receiving device detects the light with a photo diode and converts it to an electrical signal which, via an integrated circuit, controls its actions. Infrared transmitters are widely used as a means of wireless communication by remote controls for televisions and other electronic devices. Police, firefighters and ambulance drivers, for example, carry a special IR transmitter that they can use to change traffic lights from red to green within two seconds, as they approach an intersection. The main limitation of IR technology is that it requires line-of-sight between the transmitter and receiver. It cannot be used around corners or between rooms with intervening walls or ceilings. This IR Transmitter Module is designed for IR communication when paired with IR receiver module.
