Welcome! Today we are going to build an Infrared Remote Control Switch using CD4017 IC. As if you don’t know what an infrared remote control is, this is a switch that will be controlled with an infrared transmitter. Infrared remote controls (transmitters) are very common today that almost every home appliance comes with one. So I think it will be fun and of course bring you a bit closer to becoming James Bond (at least among your friends) when you can control your room lights with your television remote control.
The Infrared Remote Control Switch is very simple because it uses few components which you can find in any electronics parts or hobbyist shop around you.
Schematic Diagram
Components List
| IC1 – CD4017 x 1 | |
| T1 – A1015 PNP transistor x 1 | Buy here |
| T2 – BC141 NPN transistor x 1 | Buy here |
| TSOP1738 X 1 | |
| R1 – 220kΩ Fixed value Resistor x 1 | Buy here |
| R2, R4, 220Ω Fixed value Resistor x 2 | Buy here |
| C1 – 100uf/16v Electrolytic Capacitor | Buy here |
| C2 – 0.1uf Capacitor | Buy here |
| RL1 – 6Volts / 100 Relay | |
| D1 – IN4001 PN Diode | |
| For driving AC Load with TRIAC | |
| TRIAC1 – BT136 TRIAC | Buy here |
| R5 – 560Ω fixed value resistor | Buy here |
How the Infrared Remote Control Switch works
Remote control that comes with most home appliances transmits infrared signals at about 38 KHz. These infrared rays are received by the TSOP1738. The signal is then amplified by transistor T1 and fed to the CD4017 IC. The CD4017 is a decade counter, which means, there are 10 outputs (Q0-Q9) which will go high progressively, each time the IC receives a signal through its clock input, pin 14. Pin 4 (Q2) of the IC is connected to the Reset (pin 15) of the IC to reset the counter at every third clock input. And since we are using a PNP transistor for T1, at power ON, the transistor will be ON and hence send the first signal to the IC which will make Pin 3 (Q0) of the IC to be high. A red LED via a current limiting resistor is connected to this Pin 3 to indicate that the switch is in OFF state. When the TSOP1738 module receives an infrared signal, pin 3 (Q0) becomes low and Pin 2 (Q1) is turned high. A green LED via a current limiting resistor, is connected to this Pin 2 (Q1) to indicate that the switch is in ON state. Transistor T2 is connected to this Pin 2 via a current limiting resistor to amplify the current and drive a relay. Diode D1 is a freewheeling diode to protect transistor T2 from back EMF when the relay is switched off.
Driving AC Load with TRIAC
Of course electromagnetic relays are common for turning something ON or OFF but if you are like me, that is irritated by the “clicking” sound of the electromagnetic relays, and you want to Power ON/OFF an AC load with the Infrared Remote Control Switch, you can replace the Electromagnetic Relay with a Solid State Relay, Triac. Below is the updated diagram for the little modification.
Application of the Infrared Remote Control Switch
The Infrared Remote Control Switch can be use to switch ON/OFF electronic devices (bulb, Fan, etc) using any infrared remote control.
Demonstration video of the Infrared remote control switch
The video below demonstrates the working of the infrared remote control switch triggering a relay.
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