This neat little 12v PIR sensor has survived a year in the great outdoors, partly because it uses MOSFETs for switching rather than a relay. But it comes supplied without a daylight sensor, so it has always turned on during the day, wasting precious solar generated battery power. Here I fit the missing CdS (cadmium sulphide) light dependent resistor (LDR) to ensure it operates at night only.
![](https://i.ytimg.com/vi/tF_wTGdKN_g/maxresdefault.jpg)