Passive Infrared (PIR) Sensor | 被动红外传感器
A passive infrared (PIR) sensor is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. All objects with a temperature above absolute zero emit heat energy in the form of radiation. Usually this radiation isn't visible to the human eye because it radiates at infrared wavelengths, but it can be detected by electronic devices designed for such a purpose.
被动红外（PIR）传感器是一种电子传感器，用于测量其视场内物体发出的红外（IR）光。 所有温度高于绝对零度的物体都会以辐射形式释放热能。 通常这种辐射对于人眼是不可见的，因为它在红外波长辐射，但是可以通过为此目的设计的电子设备来检测。
