Design of infrared communication circuit based on single chip microcomputer

The circuit introduced in this article was originally an actual circuit used for time correction and meter reading in a time-sharing electric meter. It's simple and practical. Using the asynchronous communication port of the microcontroller, using the infrared light transmitting tube sir-563 and the infrared light receiving ic tube rpm6938 to realize the function of receiving and sending point signals, the half-duplex two-way communication function can be realized. The communication distance is about 10 meters, and the asynchronous communication baud rate is 1200.

Circuit principle: The infrared sending circuit is composed of a 4001mos NOR gate 38khz oscillator, a serial port sending control gate circuit and an infrared light emitting tube sir-563 drive output circuit. When the txd end of the serial port of the microcontroller is '0', the infrared light emitting tube emits 38khz modulated infrared light. When the txd terminal is '1', the emission tube does not emit light. See Figure 1. The infrared receiving circuit is the infrared receiving specialized integrated circuit rpm6938. When receiving 38khz modulated infrared light, the output terminal of rpm6938 is '0', which is usually '1'. It can be connected with the serial port transmitting and receiving terminal rxd of the microcontroller.