With this system you permanently eliminate the problems you might have with classic systems:

Barriers: the affected area must always have a free field, so materials left out of place do not allow insertion or generate continuous and repeated alarms.
Volumetric: the affected area must always have a free field and must be as stable as possible, therefore cover sheets that begin to move on windy days, animals such as birds or cats and finally residents who look out of the window generate continuous and repeated alarms.

Sensor lines: