A few years ago, human body induction lights were mostly used in residential corridors, public toilets and other places. "When people come, the lights are on, and they are off", making them extremely common in life.
In recent years, more and more intelligent human body induction lights have been applied to family life, bringing a lot of convenience to our lives.Especially for families with babies and elderly people, they often need to get up at night. After installing the human body sensor light, you can avoid the problem of finding a switch to turn on the light in the dark. Moreover, the light source of the general induction lamp is soft, does not produce dazzling sensation after lighting, and is friendly to the eyes, which makes the human body induction lamp more popular.
The human body sensor lamp is actually a kind of sensor lamp designed and developed by using the new technology of infrared and pyroelectric principle to sense human body activity information. It is a product specifically used to detect and sense human body activity information.When a person or an object with temperature enters the sensing range of the module, the sensing module will output a high-level pulse signal or a high-level delay signal. The output sensing pulse or delay signal can directly drive the LED indicator, LED lighting.The human body has a constant body temperature, usually 36-37 degrees, which emits infrared rays of a specific wavelength. The pyroelectric sensor is used to detect the infrared rays emitted by the human body.
The 9.5um infrared rays emitted by the human body are enhanced by the Fresnel lens and concentrated on the infrared induction source. The infrared induction source usually uses pyroelectric elements. This kind of element will lose the charge balance when the temperature of the infrared radiation of the human body changes. After the charge is released, the subsequent circuit can trigger the switching action after the detection and processing. If the person does not leave the sensing range, the switch will continue to be turned on; after the person leaves or there is no action for a long time in the sensing area, the switch will automatically delay the load to turn off.
Among them, there is an important component-Fresnel lens.
The Fresnel lens has two functions: one is focusing; the other is to divide the detection area into a number of bright and dark areas, so that moving objects entering the detection area can produce changes in the PIR in the form of temperature changes. Infrared signal.
When the Fresnel lens is not used, the detection radius of the sensor is less than 2 meters. When the Fresnel lens is installed, the detection radius of the sensor can reach 10 meters. The pyroelectric sensor can only be used with the Fresnel lens to play its maximum effect.