Infrared remote control switch circuit diagram

The infrared remote control switch introduced in this example can be turned on and off using the remote control of TVs, DVD players, VCRs and other home appliances, without the need for a dedicated remote control. This remote control switch can be used to control appliances such as lights and exhaust fans.

How the circuit works

The infrared remote control switch circuit consists of a power supply circuit, a remote control receiving circuit, a counter circuit and a control execution circuit, as shown in Figure 3-1.

The power circuit is composed of power switch S, step-down capacitor Cl, resistor Rl, Zener diode VS, rectifier diode VD and filter capacitor C2.

The remote control receiving circuit is composed of the special component ICl of the infrared receiver, resistor R2, and capacitor C3.

The counter circuit consists of a serial counter integrated circuit IC2, a resistor R3, and a capacitor C4.

The control execution circuit is composed of resistors R4, R5, transistor V and transistor VT.

Infrared remote controls used in home appliances such as televisions send about 10 sets of remote control code pulses per second , with a certain interval between each set of remote control code pulses. The infrared receiving head ICl receives the infrared remote control signal emitted by the remote controller and demodulates it before outputting it. After integration by R2 and C3 (filtering out the coded information in each group of pulses), it is increased from pin 1 of IC2 as the pin of lC2. Counting pulses (approximately 10 pulses per second). After 1C2 receives 8 pulses (about 0·8s), its pin 6 changes to low level or high level, causing V and VT to be turned on or off, and the working power supply of the load (electrical equipment) is turned on or off. disconnect.

Component selection

Rl-R5 uses /4W carbon film resistor or metal film resistor.

C1 uses polyester capacitors or CBB capacitors with a withstand voltage of more than 400V; C2-C4 all use aluminum electrolytic capacitors with a withstand voltage of 16V.

VD uses 1N4007 silicon rectifier diode.

VS uses 1/2W, 6·2V silicon Zener diode.

V selects 59015 or 58550, C8550 silicon PNP transistors.

VT uses 3A, 400V double interrogator thyristor.

ICl uses a miniature integrated package infrared receiver for televisions (with a cover or a translucent color filter when used), and IC2 uses a CD4024 7-bit binary serial counter integrated circuit.

Circuit debugging

After the circuit is installed, connect the voltage and load, and change the resistance of R5 so that the AC voltage between the Tl and T2 poles of VT is less than 3V.