pir motion sensor switch circuit schematic

Security Light & Switch with PIR Sensor

Moderately priced Passive Infrared PIR Sensor modules are now widely available. By using these readymade and pre-configured PIR sensors, even an average electronics hobbyist can construct his/her own Motion Sensor Unit.
The one evening project presented here is based on a common and very popular PIR module SB0061, priced below $7.
Check out the updated version of this circuit.

SB0061 is a pyroelectric sensor module,developed for human body detection. A PIR detector combined with a fresnel lens are mounted on a compact size PCB together with an analog IC (SB0061) and limited components to form the module. High level output (3.3V) of pre-settable variable width (5Secs -18 Minutes) is provided.

Circuit diagram of the PIR Motion Sensor Light and Switch based on SB0061 shown here can be used for security or corridor lighting in power saving mode. The 12V DC supply required for the whole circuit can be fed from any standard 12V ac mains adaptor/battery.

Working of the circuit is simple and straight forward. When any movement is detected within near 5-6 metres, around 3.3 Volt is appeared at the base of Transistor T1 and it conducts to fire the next relay driver transistor T2. As a result, the 12V DPDT relay is energised to power the White LED through current limiting resistor R3. Spare relay contacts can be used as a switch to control any suitable external load. The white LED and the relay remains ON for a duration based on the mono time setting in SB0061, ie from 5 Secs to 18 Minutes.

PIR Motion Sensor Circuit Schematic

pir motion sensor switch circuit schematic


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  • caballero marvic

    Good day,
    Im Marvic, a graduating student of BS ECE, I wanna ask something about the specification of PIR sensor because Im conscious about its function,(can radiate body temp. “IR” or can detect motion only) this is the device i wanna use for my thesis. Can PIR sensor response to the body temperature and what its percentage to detect the body temperature of a person? Because this device used as a switch of light as i wanna proposed to my thesis..

  • Jim Keith

    I think you wired to the NC contacts rather than the NO contacts. This circuit may have difficulty driving the relay.

    Please refer to my update on this circuit:

    Paste this link into your browser address field…

    • shail verma

      Thanx for suggestion, i checked out for NC and NO contacts but it didn’t work .One more thing since M using 5V PIR, Do i need to change capacitors and resisters value as i am giving less voltage(5V) to PIR. for this I am using transformer (transformer is attached for PIR input only).

  • shail verma

    Hello Sir,
    Am not much in the electronics, i’ve made the same circuit, except that i’ve used 5v PIR and therefore transformer to decrease 12v to 5v for the PIR. but my circuit is not working. the LED remains on at all the time, even when we remove PIR. what could be the reason for such behavior. pls reply asap.

  • sehil

    top circiut,,super,working,pls everyone must do this…….

  • Prakash


    The very detail of the project is mentioned in the link above(by Jim Keith)

  • abdulhamed


    nice project , i need some help to understand it and to help me in me Graduation Project

  • Prakash


    I did the circuit as per your link.It is working perfectly.Thank you very much for your quick response.I just need one clarification
    *I have 5V PIR sensor module .When i asked electronic shop, where i purchased this PIR module, they said that i can use 9V batery.
    What is your comments on this.Is it ok? or it will damage the PIR module.

  • Prakash

    Thank you Jim.

    I will wait for your post.

  • Prakash

    Hi ..

    I made the above circuit.But at the relay input i get only 3.3volts,with which i am unable to operate 5volt relay.

    My circuit has following changes
    1)PIR module is BISS0001
    2)The supply voltage is 9v.

    Please help me to resolve the issue.

    • Jim Keith

      No, it cannot work as shown in this circuit unless you have a relay that picks up at a very low voltage. Relays are generally specified to pick up at 75% voltage (3.75V in this case), but below this voltage is not guaranteed.

      I will attempt to post an updated circuit that will operate properly.

  • Jason

    Hello Sir, I am interested in using your project as a base circuit in my research project. I would like to ask if it is possible to replace the 12V relay with a 220V one to power a CFL bulb and other electrical appliances?

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