Multymeter.com – Electrical Engineering: A PIR (Passive Infrared) sensor is an electronic sensor that functions as a switch for electrical installations. It works similarly to a conventional switch, connecting and disconnecting the electric current for lighting. However, a PIR detects movement by recognizing changes in infrared radiation (heat) emitted by moving objects, such as humans or animals. This automatically disconnects and reconnects the electric current without human touch, like a conventional switch.
PIR sensors are passive; they do not emit their own energy for detection; they only receive radiation from the surrounding environment. These sensors are widely used in security systems, automatic lighting, and other presence detection devices because they are efficient, compact, and require little power.
How a PIR sensor works is as follows:
- Detecting Infrared Radiation:
Any object with a temperature above absolute zero emits heat energy in the form of infrared radiation. A PIR sensor detects rapid changes in this radiation. - Detecting Area Changes:
This sensor uses a Fresnel lens to divide the detection area into several zones. When a person or object moves across these zones, their body heat will transfer from one zone to another. - Converting Changes into Signals:
The changes in infrared radiation received from these zone movements will be translated by the sensor into changes in output voltage. - Triggering Detection:
This voltage change is then converted into a signal that can activate other devices, such as alarms or lights.
PIR Sensor Uses:
Security Systems: To detect intruders and notify homeowners.
Automatic Lighting: To turn on lights when movement is detected in dark areas.
Presence Detection: To detect the presence of humans or animals in a room.
Automatic Devices: In various electronic applications that require motion detection for convenience and security.
PIR sensors are ideal as light switches for bathrooms, stairwells, warehouses, basements, or whatever you need.
Installing a PIR sensor to replace a home switch is quite easy. Simply connect the line cables to the IN and OUT lines, and the switch is mounted directly on the wall to replace the home switch.***