What is the primary purpose of a PIR?

The primary purpose of a Passive Infrared (PIR) sensor is to detect infrared radiation emitted by objects within its field of view, which is particularly useful for identifying the presence of a person or an animal based on their body heat. When a PIR sensor detects a significant change in infrared radiation, indicating movement, it triggers an alarm or alert system. This capability makes PIR sensors essential components in security systems, as they effectively monitor for intrusions based on thermal energy.

While some options focus on capturing environmental changes or providing additional features, these do not align with the core functionality of a PIR in the context of intrusion detection and security. The specific focus on recognizing the image or heat signature of an intruder underscores the effectiveness of PIRs in safeguarding premises against unauthorized access.