I also have a good old PIR sensor. It is hc-sr501 motion sensor which also available in Ebay and Aliexpress for less than one dollar.
This sensor is really hard to use in outdoor environment. It has a lot of false positive due to cloud and sun.
So, I combine the hc-sr501 & RCWL-0516 like below.
The PIR sensor is the primary detector in this case. When it detect a motion, it will enable the cds pin on RCWL-0516. At that point, if RCWL-0516 detect a motion as well, then the vout pin on RCWL-0516 will output a binary one to indicate a motion. Doing this will reduce the false positive when you use a PIR sensor outdoor.
Installed
