PIR is the abbreviated from “passive infrared” sensors. It is called passive because the sensors themselves do not emit, but only perceive radiation with wavelength of 7 to 14 microns. PIR sensor has got a sensing element responding to changes in thermal radiation. If it remains constant, no electrical signal is generated.

The PIR sensor of the camera detects any movement of thermal objects (animals, people) within its field of view. The field of view of the sensor is formed by a Fresnel lens, which is on the front of the camera. The Fresnel lens is a compound lens. In the camera this lens provides a wider viewing angle of 60 degrees for the PIR sensor.

Due to the above-listed features of the PIR sensor false alarms are possible. To minimize them you should install your camera in a proper way. For example, do not point the camera at metal objects (doors, barrels) which can heat up in sunny weather and trigger false alarms of the sensor. Also do not install the camera near radiators or point it at them.