Infrared remote control delay light circuit

Infrared remote control delay light Infrared remote control delay light is suitable for situations where temporary use is needed at night. This kind of lighting does not need to be turned off by the remote control after it is turned on by the remote control. Instead, it is automatically turned off after a delay through the delay circuit that has been set in the circuit. The delay time can generally be set to 1"2MIN, and its operation can use the infrared remote control transmitter without modulation signal that has been introduced before. Circuit schematic diagram: Circuit principle: The circuit consists of an infrared receiver and a monostable delay The circuit is composed of a thyristor circuit, as shown in the figure. The infrared receiver circuit is composed of CX20160A and photodiode VD. In this circuit, the center frequency of the IC has been set to f0=40khz by the bandpass filter center frequency setting resistor R. It is basically applicable to most infrared remote control transmitters. When the photodiode VD receives the transmission signal from the transmitter, the output terminal 7 of the IC outputs a low level. In the monostable delay circuit, the 555 circuit is connected to RP and RP. C forms a pulse-activated monostable trigger, which is triggered by a negative pulse or low level through pin 2, causing it to flip. Normally, pin 7 of the IC outputs a high level, and pin 3 of the IC outputs a low level. When pin 7 outputs low level, pin 2 turns IC2 over, and pin 3 becomes high level. This high level triggers the thyristor VS through R, causing it to turn on and the monostable circuit turns on. After triggering the flip, it enters a temporary stable state. At this time, the power supply charges C through RP. The time required for C to charge is the delay time of the monostable trigger. This time TD=1.1RPC5. Due to the use of the adjustable resistor RP, The transient stabilization time of the monostable circuit can be adjusted as needed. When C5 is charged so that the positive terminal voltage rises to 2VDD/3, the monostable circuit flips, pin 3 of the IC returns to low level, and the triac VS turns off. off, the light goes out. Component selection and production: VD2 should use a 6.2V zener diode, SCR1 should use a 1A/400V unidirectional thyristor or bidirectional thyristor. There are no special requirements for other components. Installation and debugging: Component installation. : Resistor, adjustable resistor, capacitor, MIC, transistor, inductor L, IC Debugging method: After the components are installed correctly, power on for debugging. The debugging is mainly divided into two parts. One is the monostable delay circuit composed of 555. When debugging, first measure the voltage value between IC555 pins 4, 8 and 1, which should be 6V. When the voltage changes, you should check VD1, VD2, C1, R1, focusing on whether VD2 is damaged. When checking this part of the circuit, Be very careful, otherwise you will overpower the 220V AC. When debugging the 555 monostable delay circuit, touch the second pin of IC2 with a test lead. If the lamp H does not work, check it. Whether there is an error in the circuit of IC2, the values ​​of R2 and C7 determine the length of the delay time. The second part is the infrared receiving circuit composed of IC1 CX20106. The infrared signal is input from pin 1 of IC1 and output by pin 7. The central frequency setting resistor of the bandpass filter can change the receiving frequency of the receiver by changing its resistance. C4 and R7 determine the amplification gain. The total gain of IC1 is designed to be 77"79dB. At this gain, pin 7 of IC1. The output pulse amplitude is about 3.5"5V. C2 is the integrating capacitor, and its capacity is generally 330PF. When C2 is larger, although the anti-interference ability can be improved, it will also lengthen the low-level duration of the output pulse, resulting in a shorter remote control distance.