Satellite receiver remote control AC on/off circuit

This article introduces a remote control AC on/off circuit for a satellite receiver, which can be installed in the receiver and use the original remote control to realize the remote control delayed AC on/off function. The circuit structure is simple, the components are easily available, and it is easy to make. It is especially suitable for amateur electronics enthusiasts to make their own. Working principle: The circuit is shown in Figure 1. The mains power supply is stepped down by the transformer T, rectified by the rectifier diodes D1~D4, stabilized by the voltage stabilizing blocks 7810 and 7805, and filtered by the capacitors C1, C2, C5 and C6 to power the entire circuit. Turn on the switch K, and the 10V voltage output by the voltage stabilizing block is added to the delayer. At this time, the pin of IC1 is low level, the pin output is high level, LED1 lights up, relay J1 is powered on, and contact J1- 1 pulls in, and the satellite receiver is powered on. At this time, the receiver on/off control level output terminal is high level, VT1 is cut off, and VT2 is turned on, keeping the pins of IC1 and IC1 at low level. When the satellite receiver is in standby, the on/off control level output terminal is low level. At this time, VT1 is turned on, VT2 is turned off, and the pin voltage of IC1 slowly increases. When this voltage rises to 2/3Vcc, the pin of IC1 changes from high level to low level, and LED1 goes out. Relay J1 loses power, contact J1-1 is disconnected, and the satellite receiver AC is shut down. After the satellite receiver is switched off, the original remote control can still be used to turn it on. The working principle is: when the integrated infrared receiver M receives the signal from the remote control, the pulse wave at its output end is filtered by C7 and becomes low level. At this time, the voltage on C8 is slowly discharged through R8. When the voltage is lower than 1 . At 55V (actual measurement), VT5 is turned off and VT6 is turned on, causing the pin of IC1 to drop to low level, the pin jumps to high level, LED1 lights up, relay J is powered on, and the satellite receiver is powered on. LED2 is the remote control signal receiving indicator light. When M receives the remote control signal, the signal at the output end is amplified by VT3 and VT4 to make LED2 light up. Component selection and production: M chooses an ultra-small integrated infrared receiver, which contains circuits such as infrared photoelectric conversion, amplification, frequency selection, shaping, sunlight filtering and electromagnetic shielding. It looks like a medium-power triode (Figure 2) , the raised front is the light-receiving surface, you can also use the infrared receiver in Figure 3. It is larger than the one in Figure 2. Please note that the pin arrangement is different. IC1 uses CMOS 555 time base circuit, such as NE555, 5G7555, etc. J1 selects a small DC relay with a pull-in voltage of 9~12V, such as JZC-23F. VT1, VT3, and VT4 use PNP-type low-power transistors such as C9012, and VT2, VT5, and VT6 use NPN-type transistors such as C1815. T selects a 3VA low-power power transformer with an input voltage of 220V and an output voltage of 15V. There are no special requirements for the remaining components. Figure 4 is the printed circuit board diagram of the remote control AC shutdown circuit. As long as the components selected for this circuit are of good quality and the welding and installation are correct, it can generally work normally without debugging. In order to improve the anti-interference performance, the infrared receiver M needs to continuously receive the remote control signal (LED flashing) for more than 7 seconds when the remote control is turned on, so as to avoid controlling the TV program, volume, etc. for too long and causing the satellite receiver to accidentally start up. If you need to shorten the remote control start-up time, you can reduce the capacity of C8 or the resistance of R8. When C8 is 10μF and R8 is 1.5MΩ, the remote control start-up time is shortened to 3 seconds.