The principle of infrared sensor switch and its application

The sensor switch refers to the human body infrared intelligent sensor switch, which is a switch that is automatically activated when someone passes the infrared sensing detection area.

Ordinary human body emits infrared light with a specific wavelength of about 10um. The sensor can be specifically designed to detect the presence or absence of this infrared light. When the human body irradiates the sensor with infrared radiation, the charge will be released by the pyroelectric effect. Subsequent circuits can generate control signals after detection and processing. This specially designed probe is only sensitive to infrared radiation with a wavelength of about 10 μm, so objects other than the human body do not cause probe movements. The probe contains two pyroelectric elements connected in series or in parallel with each other, and the polarity of the two electrodes formed is exactly the opposite. The environmental background radiation has almost the same effect on the two pyroelectric elements, causing them to cancel each other out. Therefore, the detector has no signal output. Once the person invades the detection area, the infrared radiation of the human body is partially focused by the mirror and received by the pyroelectric element. However, the heat energy received by the two pyroelectric elements is different, and the pyroelectricity is also different and cannot be canceled, so the detection signal is output.

In order to enhance sensitivity and reduce white light interference, the Philippine clay filter lens is usually covered on the radiation surface of the probe. According to different performance requirements, the Philippine mud filter has different focal length (sensing distance), resulting in different Monitor the field of view, the more the field of view, the more rigorous the control.

The sensor has a spectral range of 1 to 10 μm and a center of 6 μm. Both are in the infrared wavelength range and are determined by the optical properties of a silicon window mounted on a TO-5 type metal case.

Pyroelectric infrared sensors are not only suitable for anti-theft alarm sites, but also suitable for high-voltage electrical and X-ray, gamma-ray industrial non-destructive testing of human injuries.

The human body infrared sensor switch is suitable for automatic lighting, ventilation and other purposes in corridors, corridors, warehouses, garages, basements, and toilets, and truly reflects the modernization of building intelligence and property management.

Features : Based on the infrared technology of automatic control products, when someone enters the switch sensing range, the special sensor detects the change of the human infrared spectrum, and the switch automatically turns on the load. The person does not leave and is in the activity, the switch continues to conduct; After the person leaves, the switch delays and closes the load automatically, the person is bright, the person is away from the light, friendly and convenient, safe and energy-saving.

The false alarm rate of human body infrared pyroelectric sensors has a great relationship with the location and mode of installation. The correct installation should meet the following conditions:

a. The sensor switch should be 2.0-2.4 meters away from the ground.

b. Sensors are far away from air-conditioning, refrigerators, stoves, etc., which are likely to cause air temperature changes.

c. There must be no screens, furniture, large bonsai or other partitions within the sensor switch detection range.

d. Sensor switches should not be installed where there is strong airflow.