How the human body infrared detector works

The human body generally emits infrared light of a specific wavelength of about 10 microns. The human body infrared detector works by detecting infrared radiation emitted by the human body at about 10 microns.

The detector collects about 10 micrometers of infrared radiation emitted by the human body and collects it on the infrared sensor. Infrared sensors usually use pyroelectric elements, which release charge when they receive a change in the infrared radiation temperature, and generate an alarm after detection processing.

This detector is aimed at detecting human radiation, so the radiation sensitive element must be very sensitive to infrared radiation with a wavelength of about 10 microns. In order to increase the infrared radiation sensitivity of the human body, a special filter is usually covered on the detector, so that the environmental interference is obviously controlled. The sensor of the infrared detector includes two pyroelectric elements connected in series or in parallel with each other, and its two polarization directions are exactly the opposite. Therefore, the environmental background radiation has the same effect on two pyroelectric elements, so that it produces a pyroelectric effect. Counteract each other, so the detector has no signal output. Once someone enters the detection area, infrared radiation of the human body is focused by the lens and is received by the pyroelectric element. Since the pyroelectric element received by the two pyroelectric elements is different in heat, the pyroelectricity is also different, so it cannot be canceled out, and the signals are processed. Call the police.

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