PIR sensors, or Passive Infrared Sensors, are electronic devices that detect motion by measuring changes in infrared radiation. They are commonly used in security systems, automatic lighting, and energy-saving applications. When a warm body, like a human or animal, moves within the sensor's range, it triggers the sensor to send a signal, activating an alarm or light. These sensors work best in open areas where they can cover a wide field of view. They are energy-efficient and typically require minimal maintenance, making them a popular choice for both residential and commercial use. Their ability to detect motion without direct contact enhances safety and convenience.