I’ve been reading the "Rain" series of contemporary fiction novels, and Rain (an assassin) has a detector he keeps in his pocket that "detects" some kind of wave length (side-band? or similar I think it was called) that video camera’s produce. The detector also detects audio surveillance. The author never differentiates between wireless and hard-wired devices, this little thing picks up everything within about 10 meters or so if I recall correctly.

I’m just wondering if that is actually possible or if it is literary license. If it is possible, how?

I have one elderly mother and a mentally retarded brother who lives with me.

I kind of worry about them when I work during the day, although I live in a safe rural community and have great neighbors.

Are those home video and audio surveillance monitors worth getting?
When I'm home I have a shotgun just in case something happens.