Wireless switch for intelligent home lighting control based on AT89S52

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

Wireless Crystal 3.2*2.5mm 3225 25M (25.000MHZ) 12PF 10PPM 20PPM 30PPM

1 system design

With the continuous development of electronic technology, wireless technology plays an increasingly important role in intelligence. The design is a wireless remote control switch system capable of realizing remote Lighting control, and is composed of a transmitting system and a receiving system. The system uses a wireless transceiver module to form a radio frequency transmitting and receiving circuit. The transmitting part is mainly composed of a key addressing circuit, an encoding circuit and a transmitting module; the receiving part is mainly composed of a receiving module, a single chip control circuit and a load circuit.

The transmitting system is powered by a 12 V dry battery. The receiving system is powered by three 1.5 V dry batteries. The MCU is powered by a 5 V DC power supply. The power supply system is energy efficient and simple.

2 system implementation

2.1 Component selection and system block diagram

Considering the compatibility, practicability, low cost and energy saving of the system, the AT89S52 single-chip microcomputer is used, and the PT2262/2272 wireless transceiver module is used to realize 315 MHz wireless communication. The AT89S52 microcontroller is a low-power, high-density CMOS 8-bit microcontroller manufactured by ATMEL's non-volatile memory technology. It contains 8 KB ISP (In - system programmable) and can be erased and erased 1000 times. Read-only program memory, compatible with the standard MCS-51 instruction set and 80C51 pin structure, provides a cost-effective solution for many embedded control applications.

PT2262/PT2272 is a low-power, low-cost general-purpose codec circuit manufactured by Pucheng, Taiwan. The PT2262/PT2272 can have up to 12 bit (A0-A11) tri-state address pin (dropped, Connected to high level, connected to low level), 12 bit (A0-A11) Any combination of tri-state address terminal pins can provide 531 441 address code, PT2262 can have up to 6 bit (D0-D5) data terminal pins, set The fixed address code and data code are serially output from the 17-pin [2].

The system block diagram of the circuit is shown in Figure 1.

2.2 System circuit diagram

The system circuit consists of a wireless transmitting system and a wireless receiving system.

(1) Wireless transmission system circuit (Figure 2): It is mainly implemented by PT2262 chip. Circuit PT2262 encodes the key signal and can control 4 channels. In Figure 2, pins 1~8 of PT2262 are coded address terminals. Each address terminal can be set to "high level" (the pin is connected to 12 V), "low level" (the foot is grounded), and "floating". State. Pins 10~13 are coded data inputs D3~D0 (using 4-bit data), and a button is connected to each data terminal to control different devices. When the button is pressed, the button applies a voltage of 12 V to the corresponding data terminal, and the data terminal transmits the signal through the crystal oscillator. The PT2262 will encode according to the address code setting and input data, and output the encoded pulse from pin 17. The wireless communication is controlled by the coded pulse [2-3]. When the 17-pin pulse is "1", the oscillator composed of V1 operates to generate a high-frequency signal of 315 MHz and is transmitted; when the output pulse of the 17-pin is "0" The oscillator consisting of Vl stops working.