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 ...

It is likely that many of us will at some time have experimented with motion detectors. Our Arduinos, Raspberry Pis, Beaglebones or whatever will have been hooked up to ultrasonic or PIR boards which ...