A pyroelectric infrared sensor is a type of motion sensor that detects changes in the infrared radiation emitted by living beings and other objects.
It works by detecting the small changes in temperature that occur when an object moves in front of it. Pyroelectric infrared sensors are commonly used in security systems, lighting controls, and other applications where motion detection is required.
Pyroelectric Infrared Sensor an Overview
The sensor consists of a thin layer of pyroelectric material, such as lithium tantalate or polyvinyl fluorid (PVF2), that generates an electric charge when heated or cooled. When a warm body enters the field of view of the sensor, it causes a change in the temperature of the pyroelectric material, which in turn generates an electric charge.
The charge is then measured by a circuit connected to the sensor, which triggers an alarm or other action if the change in charge is above a certain threshold.
Pyroelectric infrared sensors are passive devices, meaning they do not emit any energy and rely solely on detecting the energy emitted by other objects. They are highly sensitive and can detect even small movements, making them ideal for security applications.
However, they can also be triggered by changes in temperature caused by factors other than human or animal movement, such as changes in ambient temperature, sunlight, or wind.
To reduce false alarms, pyroelectric infrared sensors are often used in combination with other types of sensors, such as microwave or ultrasonic sensors, to provide more accurate motion detection.
