Infrared remote control switch circuit

As shown in the figure, the infrared remote control switch is composed of an infrared transmitter and an infrared receiver. Figure (a) is the circuit diagram of the infrared transmitter. After pressing AN, the IC (NE555) self-excited multivibrator oscillates to generate a 35kHz high-frequency signal, which is output from pin 3 to drive the infrared light-emitting tube TLNl04 to emit an infrared signal. Two tubes are connected in series to increase the infrared light intensity and emission radius. Adjusting W can change the infrared light frequency so that it falls within the frequency selection range of the receiver. Figure (b) is the infrared receiver circuit diagram. When the infrared receiving tube TLPl04 receives the infrared signal from the infrared transmitter, it is amplified and tuned by IC1 and then output from pin 1 to the input of IC2. After amplification and other processing, it is output from pin 8 to trigger the SCR to turn on or off. . Each time the receiver receives a transmission signal, the output state of pin 8 of IC2 flips once, that is, from low level to high level, or from high level to low level. So every time AN ​​is pressed, SCR changes state to realize the on and off function.