DIY Passive infrared sensor

Hello my friends, today we will make an existing circuit PIR sensor motion

A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. PIR sensors are commonly used in security alarms and automatic lighting applications.

PIR sensors detect general movement but do not give information on who or what moved. For that purpose, an imaging IR sensor is required.

PIR sensors are commonly called simply “PIR”, or sometimes “PID”, for “passive infrared detector”. The term passive refers to the fact that PIR devices do not radiate energy for detection purposes. They work entirely by detecting infrared radiation (radiant heat) emitted by or reflected from objects. All objects with a temperature above absolute zero emit heat energy in the form of electromagnetic radiation. Usually, this radiation isn’t visible to the human eye because it radiates at infrared wavelengths, but it can be detected by electronic devices designed for such a purpose.

This component not commonly use alone it used with other components in the PIR module

This circuit operated on 5 voltage in real life and Output 5-volt when every Organism cross in front of the sensor the object will rays IR and PIR will

generate Output (+5v) we will give the output to basing transistor :

you can control the sensitivity by the yellow Pot, the other pot will control the time delay


transistor BC547

relay 12volt

12volt adaptor or battery

Regulator 5 Volt

PIR module

relay module circuit :slight_smile:

explanation of the circuit:
We will but the module instead of switch, connect the output of sensor with pot-base and the Vcc of PIR to (5+) of lm7805 and then GND to general GND, the relay will switch bulb or Alarm or any 220v when any object cross light will be turned on
Link of the circuit

feel free to ask me any question:


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