Multi-channel remote control switch circuit using dedicated encoding/decoding integrated circuit

The CNC multi-way switch introduced in this article consists of an eight-button remote control and a receiving component with eight relays. The device uses a highly stable wireless transceiver module and a remote control-specific encoding/decoding integrated circuit. It has the characteristics of high confidentiality, long remote control distance, stable and reliable performance, and low static power consumption. It can remotely control the switches of eight-way household appliances. The remote control circuit of the CNC multi-way switch is shown in Figure 1. The remote control is mainly composed of three integrated circuits. U1 (74LS148) in the circuit is an 8-3 line coding integrated circuit, which can compile eight-way switch signals into BCD code output. U2 (VD5026) is a dedicated coding integrated circuit for remote control. The integrated circuit has a total of 8-bit address code (~pin) and 4-bit data code (~pin). This circuit only uses 3-bit data codes, and the 8-bit address codes can be combined in any combination, that is, connected to the positive, negative pole of the power supply, or left floating to form three coding states. There are 6561 different coding states to distinguish different devices. U3 (YG300U-S) is a wireless transmitter module. When no key is pressed, U1, U2, and U3 have no power supply and do not work, so they do not consume power. When a button is pressed, the power supply is supplied to the three integrated blocks through the diodes. At the same time, the input data is encoded by 74LS148 and input data from its pins to the pins of VD5026. The BCD code is encoded by VD5026 and then The serial encoding pulse mode is input to the pin of the transmitting integrated block YG300U-S through the pin, and then is emitted outward from the pin. The receiving component part is shown in Figure 2. U4 is the receiving module YG300U-R; U5 is the remote control special decoding integrated circuit VD5027, and its ~ pin is an 8-bit three-state address encoding end. When used in conjunction with VD5026, the sending/receiving address is required The codes must be consistent to achieve data remote control; U6 is a 3-8 line decoder 74LS138. After the high-frequency carrier signal emitted by YG300U-S is received by the antenna, it is input by the pin of YG300U-R. The effective signal sent by the transmitting module is selected through its internal frequency selection circuit. It is then filtered, amplified and shaped and then output by the pin. When the pin of VD5027 is confirmed by the internal comparison circuit to be consistent with the address code of VD5026, the pin outputs a high level to the pin of 74LS138 to start the 74LS138 to start working. At the same time, the data is also output from the pins of VD5027 and 74LS138 to 74LS138. 4LS138's,, feet, through After the 74LS138 is decoded, the pin corresponding to the transmit key outputs a low level, and then inverts the 74LS04 and triggers the 74LS74, which latches and outputs a 6V high level, so that the relay is powered on to achieve the purpose of turning on the remote control appliance. . Press the same button on the remote control again to de-energize the relay and turn off the power to the appliance. The 74LS04 is a six-inverter, and the 74LS74 is a double-D flip-flop.