The human pyroelectric infrared sensor is based on the pyroelectric effect. When the human body emits infrared radiation, the piezoelectric ceramic material inside the sensor releases charges due to temperature changes, which are converted into voltage output through an amplifier. Specifically, in the absence of infrared radiation, the surface charge of the sensor is in a neutral state and there is no output; When there is infrared radiation (such as human body radiation), the temperature of the sensor rises, causing a decrease in charge and releasing a portion of the charge. These charges are processed by an amplifier and output as a voltage signal.

Human pyroelectric infrared sensors are widely used in infrared fields such as anti-theft alarms, visitor notifications, and non-contact switches. For example, in anti-theft alarm systems, when a human body approaches, the sensor will detect infrared radiation and output a signal, triggering the alarm system. In addition, the sensor can also be used for flame detection in smart firefighting, by receiving infrared information from flame combustion radiation and converting it into voltage signals.