The presented schematic shows how to build a simple PIR motion sensor. PIR sensors allow motion sensing, it is almost always used to detect whether someone has moved in or out of the sensors range.

Furthermore, the vacant solder pads near the three-pin interface header is for mounting a light-dependent resistor (LDR/CdS cell). This, if added, causes the detector to be operational only when the ...

Many close-proximity motion detectors use the classic, widely available passive-infrared (PIR) approach, which is effective but has limited sensitivity and adjustability, and can’t “see” through ...