First, pins and packaging

　　 Generally, the infrared receiver has three pins: VCC power positive, GND power negative, and OUT output.

　　Packaging usually includes iron shielding and epoxy plastic packaging, but the shapes are different, including chips, plug-ins, nose bridges, straw hats, cylinders, hemispheres, etc. Different manufacturers have different receiving head pin sequence and shell shape.

　　 Second, the main parameters of the infrared receiver

　　The main parameters of the infrared receiver include working current/voltage, receiving distance, receiving angle, etc.

　　The receiving distance is iron shell and epoxy resin, and the anti-interference ability is weak. The receiving surface is not blocked when the product is designed, and the receiving distance is quite good.

　　 Third, infrared receiving system

The schematic diagram of infrared transmission and reception consists of two parts: signal transmission and signal reception. The transmitter loads the corresponding digital signal, namely our remote control code, onto the carrier. The remote control code generally uses binary pulses. Each company has its own remote control code and different The transmission protocol method. At present, the carrier frequency of infrared remote control is generally 38kHz, and there are also 36kHz and 40kHz. Because the general crystal frequency is 455kHz, the frequency should be divided first when sending the signal. The general frequency division is 12, etc., 455kHz/12=37.9kHz=38kHz. As soon as the carrier carrying the signal is sent, the infrared receiving head has an infrared photodiode. At this time, through a series of projects such as expansion, the signal is finally adjusted to a current signal, converted into the necessary remote control code, and the corresponding function is output.

　　Fourth, principle

　　The receiving head is susceptible to interference from external signals, especially infrared rays. Therefore, a filter capacitor is added to the power supply of the receiving head, that is, an electrolytic capacitor and a porcelain capacitor are connected between VCC and GND. The capacity is the data provided by the manufacturer.