Principle: Infrared induction sources usually use pyroelectric elements. When the temperature of this element changes after receiving infrared radiation from the human body, it will lose its charge balance and release the charge outward. The subsequent circuit will be detected and processed. Can generate alarm signals.

How to use: Adjust the concentric ring and the infrared probe to have an appropriate focal length. The infrared light is just received by the probe, and the probe converts the optical signal into an electrical signal and sends it to the electronic circuit to drive the load. The human body infrared sensor should be kept away from air conditioners, refrigerators, stoves and other places that are sensitive to changes in air temperature.

Extended information:

Infrared light will be attenuated when propagating in media. The attenuation is very large when propagating in metals. However, infrared radiation can pass through most semiconductors and some plastics. Liquids absorb very much infrared radiation.

Infrared sensor applications can be used for non-contact temperature measurement, gas composition analysis, non-destructive detection, thermal imaging detection, infrared remote sensing and reconnaissance, search, tracking and communication of military targets.

The application prospects of infrared sensors will become broader with the development of modern science and technology. In future development, the performance and sensitivity of infrared sensors will be greatly improved.

Reference: Baidu Encyclopedia-Thermal Infrared Human Sensor