Passive Infrared Detectors

Passive Infrared Detectors

Passive infrared detectors, commonly known as PIR detectors, are electronic devices that detect motion by sensing changes in the infrared radiation levels emitted by objects in their field of view. These detectors are widely used in security systems, lighting control systems, and other applications where motion detection is required. PIR detectors are called passive because they do not emit any energy themselves, but simply detect the energy emitted by other objects. PIR detectors consist of a pyroelectric sensor, which is a crystal that generates a voltage when it detects changes in temperature, and a lens that focuses the infrared radiation onto the sensor. When an object moves within the field of view of the detector, the infrared radiation emitted by the object changes, causing a voltage to be generated by the sensor. This voltage is then amplified and processed by the detector's electronics to trigger an alarm or other action. PIR detectors are highly effective at detecting human motion, but they can also detect the motion of other warm-blooded animals and even changes in temperature caused by air currents or sunlight. To minimize false alarms, PIR detectors are often designed with advanced signal processing algorithms that can distinguish between different types of motion and filter out unwanted signals. In summary, passive infrared detectors are electronic devices that detect motion by sensing changes in the infrared radiation levels emitted by objects in their field of view. They are widely used in security systems and other applications where motion detection is required, and are highly effective at detecting human motion while minimizing false alarms.

PIR detectors, motion detection, infrared radiation, pyroelectric sensor, lens

— Thomas Johnson

CITATION : "Thomas Johnson. 'Passive Infrared Detectors.' Design+Encyclopedia. https://design-encyclopedia.com/define/passive-infrared-detectors?E=380871 (Accessed on October 14, 2026)"