Design and production of wireless multi-location control switch circuit

See the figure below for the circuit schematic.

In the figure, RX is a wireless remote control receiving module with PT2272-T4 as the core. The commonly used frequencies are 315M and 433M, and the frequency can also be customized. The matching wireless transmitting module is PT2262: PT2272 has multiple models, including PT2272-M4.M6.PT2272-L4 and PT2272-T4, which are 4-bit (6-bit) inching, 4-bit interlocking and 4-bit self-locking respectively. This system uses the self-locking type, which is characterized by connecting the corresponding data transmission key of the remote control, the receiving module PT2272-4 corresponding to the data bit outputs a high level and self-locks, and then pressing the corresponding transmission key of the transmitter, the receiving module PT2272-T4 corresponding to the data bit outputs a low level and self-locks. When the wireless receiving module outputs a high level corresponding to the data bit, the transistor Q3 is turned on, the base current of the transistor Q2 is short-circuited and the transistor Q2 is turned off, the thyristor Q1 is turned on by the trigger current provided by R1, and the load is powered on. On the contrary, when the corresponding data bit of the wireless receiving module outputs a low level, the transistor Q3 is turned off, and the transistor Q2 is turned on, which short-circuits the trigger current of the thyristor Q1 and turns off the thyristor Q1.

In this way, we can conveniently use the remote control to control the switch of the same load in multiple locations. If the light is off at this time, any control point can turn on the light by pressing the remote control. If the light is on, any control point can also turn off the light by pressing the transmitter button of the remote control. It is very convenient, just fix the remote control at the control point (the power supply of the remote control can be obtained by AC direct power supply after voltage stabilization). Since the static power consumption of this remote control receiving module is very small, it is generally within 3mA. In static state, there is a 47k resistor obtained from the mains. In static state, because the thyristor is turned off, the voltage of the ② foot of the rectifier bridge QL is higher, and the receiving module is powered through R3 and D9. Once the thyristor is turned on, the voltage of the ② foot of the rectifier bridge immediately drops to about 3V, and it can no longer maintain the power supply needs of the receiving module. For this purpose, an auxiliary power supply circuit with the boost integrated circuit BL8530 as the core is designed. In static state, the thyristor is in the off state, the cathode voltage of the thyristor Q1 to the ground is "0" (because there is no current passing, the voltage is zero), and the boost circuit does not work. Once the thyristor Q1 is turned on, there is a DC voltage of about 2V on its cathode, which is isolated by the Schottky diode D2. The capacitor Cl smoothes and obtains a DC voltage of about 1.7V. The boost integrated circuit BL8530 increases it to about 6V and isolates it through the Schottky diode to send it to the wireless receiving module to power the wireless receiving module.

The power supply voltage of the wireless receiving module determines its receiving sensitivity, that is, the remote control distance. A power supply of 4.5V or above can ensure a remote control distance of no less than 20M. Maintaining a power supply voltage of about 5V is generally practical.

This circuit changes the conventional circuit which requires a lot of wiring and increases the installation cost and adopts a novel wireless remote control method to achieve the purpose of controlling the same load in multiple locations, which has great practical significance.