Passive Infrared Sensors (PIR) are devices that detect motion by sensing changes in infrared radiation, which is emitted by objects based on their temperature. These sensors are commonly used in security systems, automatic lighting, and energy-saving applications. Unlike active sensors, PIR sensors do not emit any signals; instead, they passively monitor the environment for heat changes caused by moving people or animals. When a warm body enters the sensor's field of view, it triggers a response, such as turning on a light or sounding an alarm. PIR sensors are popular due to their low power consumption, affordability, and ease of installation, making them ideal for both residential and commercial use.