Passive Infrared Sensors

Passive Infrared Sensors

Passive infrared sensors, commonly known as PIR sensors, are electronic devices that detect infrared radiation emitted by living beings and objects in their vicinity. These sensors are widely used in security systems, lighting control, and home automation applications. The working principle of a PIR sensor is based on the fact that all objects with a temperature above absolute zero emit infrared radiation. The sensor consists of a pyroelectric material that generates a voltage when exposed to temperature changes caused by the movement of objects in its field of view. The sensor is designed to detect changes in infrared radiation, which occur when a warm body moves across its field of view. The PIR sensor is typically composed of two halves, each of which contains a pyroelectric material. When an object moves across the field of view, it causes a temperature difference between the two halves, which generates a voltage difference. This voltage difference is amplified by the sensor's electronics and triggers an alarm or activates a device connected to it. PIR sensors are commonly used in security systems to detect motion in areas where people are not supposed to be, such as hallways, stairwells, and storage areas. They are also used in lighting control systems to turn lights on and off automatically when someone enters or leaves a room. In home automation applications, PIR sensors are used to trigger the opening and closing of doors, windows, and curtains.

Infrared radiation, Pyroelectric material, Field of view, Security systems, Lighting control

— Ryan Phillips