Wireless Light Switch Circuit

light electronic switchYou may use this wireless light switch instead of physical contact with switches which may be dangerous if there is any shorting. The wireless light switch circuit described here requires no physical contact for operating the appliance.

You just need to move your hand between the infrared LED (IR LED1) and the phototransistor (T1). The IR rays transmitted by IR LED1 is detected by the phototransistor to activate the hidden lock, flush system, hand dryer etc.

This wireless light switch is very stable and sensitive compared to other AC appliance control circuits. It is simple, compact and cheap. Current consumption is low in milliamperes. The circuit is built around an IC CA3140, IRLED1, phototransistor and other discrete components.

The working of the circuit is simple. In order to switch on the appliance, you simply interrupt the infrared rays falling on the phototransistor through your hand. During the interruption, the appliance remains on through the relay. When you remove your hand from the infrared beam, the appliance turns off through the relay.

Schematic of the electronic wireless light switch circuit


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  • Name *

    its fine but ca you please include the connection of the load….. otherwise congrats.

  • Firoze

    Hi yogi
    I have connected the circuit on breadboard but it is not working sometimes I am getting 3.4v across diode

  • bright

    Please can anyone help me on this I won’t build an inverter pure sin wave,12v to 230v 5000watt but I don know the coil guage lamination and coil turns I will be so grateful this is my

  • sheik muhamed


    friends this is a common remote control circuit
    it is used for all toy cars ok

    it wil receive any signal from the remote and convert the pulse to the relay thats it,,,,,,,,,,,,,,hehhee

  • Shivam Maurya

    Can i use dc appliances like emergency light,motor fan…etc with this relay. Which works on 5-6 Volt DC.

  • gilbert sambolin

    I have been looking for a system like this myself, but I have not been successful I have looking in China’s Alibaba but many sellers say that they do not have it or make it there. Perhaps it is because I don’t want to buy hundreds.
    Any way for the benefit of all concerned those light beam activator switches are used in every supermarket check out counter they are practiclyinvisible they stop the belt when the packages reach the cashier’s reach. You can also make your own if you are handy with a soldering gun and can red a simple schematic.
    Good luck to everyone, and enjoy the new year by thanking God first.

    • Yogi

      I think you can change the receiver by using PIR (passive infrared).
      it’s movement detector.
      but you have to modify the circuit.

      another solution is using IR receiver module.

  • gayatri

    can any one answer that where does the base of L14F1 is connected….

    • Yogi

      it’s easy bro.
      base of L14F1 is equal as infrared.
      so no pinout is exist of the base.
      this component is infrared receiver.

  • Bilal

    how can we add a simple latching circuit in this schematic to keep the state upon interrupting the light? like pass finger the load is on, again pass the finger and its off??

  • akash

    i have prperly connect this circuit, but my circuit is working opposite to desired i.e. when i intrupt, my appliance blows off and when i remove my hand, my appliance blows.
    please give me the reason and solution as soon as possible.

    • Yogi


      Maybe you are reversed connect between pin 2 and 3. the effect is opposite.
      It’s Op Amp schematic.

  • Yogi

    I think it’s difficult to use 12 Volt relay. because the source is 5 volt.
    but you can use it by changing source voltage into 12 volt and reduce to 5 volt by using regulator. and the 12 volt DC can use for 12v relay.


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