Multipurpose wireless remote control switch circuit

This remote control switch adopts radio encoding and decoding method, which is not restricted by directionality, and the linear control distance is ≤100m. It can control the on/off of electrical appliances with a power of about 400W. It consists of two parts: remote control and receiving circuit. The remote control is small in size and beautiful in appearance. It can be hung on the keychain and carried with you. There are four buttons on it, which can respectively transmit four control signals. Figure 1 shows the remote control transmitter circuit. IC1 is a low-power coding transmitter chip using CMOS technology. The ~ pin is an 8-bit 3-state address setting pin. Each pin can be connected to high level, low level or left floating, thus providing 6561 (3 of 8 times square) address code, which can effectively avoid duplicate codes. In addition, ~ pin is a 4-bit data pin that can generate four control signals. When any button is pressed, the coded pulse train corresponding to the button formed by IC1 is output from the pin to modulate the high-frequency oscillation circuit. JT1 is a high-frequency resonator, which together with VT1 form a stable high-frequency oscillation circuit. In addition, VT1 also serves as a high-frequency transmitter, and the signal is transmitted through L1. Figures 2 and 3 show the high-frequency receiving and decoding control circuits respectively. In Figure 2, the signal received by the antenna is amplified by VT1 high frequency and then enters VT2 for frequency selection. The signal with the same carrier frequency as the transmitter is selected and enters IC1A for amplification. The amplified signal enters IC1B for shaping and is output by Dout to Figure 3. Din, and then sent to the pin of PT2272 after further filtering and shaping by IC2A. PT2272 is a decoding integrated circuit used in conjunction with PT2262. It also has an 8-bit 3-state address pin. Only when the address pin settings are the same as those of PT2262, can the data signal be correctly decoded and a high level be output at the corresponding output end of PT2272 . D1, R2, R3, and C1 form a circuit to eliminate button jitter to ensure the reliability of remote control operation. The positive terminal of D1 can be connected anywhere from pin to pin of PT2272, which correspond to the 4 buttons of the transmitter respectively. C2 and R4 complete the preset of CD4013, so that the output terminal of CD4013 is low level when power is first applied, that is, the controlled electrical appliance is in a power-off state. IC4 is an optocoupler with a zero-crossing trigger function. When CD4013 outputs a high level, the optocoupler works and triggers the bidirectional thyristor to conduct at the same time, outputting a 220V voltage at the output end. Using thyristors as switch control can eliminate the noise generated by using relays, and the reliability of the entire circuit can also be improved. The power supply of the receiving circuit adopts the resistance-capacitance step-down method, which realizes the miniaturization of the entire circuit. This set of boards has been fully debugged and can work normally without any processing. After installation, press the button once to power on the appliance, and press it again to power off the appliance.