This universal IR receiver works with the IR keyboard transmitter for the Running Text Display described in the February 2000 edition of Elektor Electronics. Its versatility allows it to perform simple switching tasks or complex control of test equipment remotely from a standard PC keyboard.There are two basic methods used for sending data over an infrared link. The simplest is to switch the transmitting diode on and off to represent 1‘s and 0‘s in the data stream. To save energy, these bits are made as short as possible. This however makes it more difficult for the receiver to detect the signal, especially if there are high levels of ambient light. The accepted method of overcoming this problem is to switch the transmitter diode with a carrier frequency that is modulated by the data. The receiver electronics are relatively simple and can be easily integrated along with the IR receiving diode to produce a compact device with good sensitivity and immunity to ambient light levels.