the glass breaks I use prefer line of sight, but will work with minor obstructions. You don't want a door or wall in the way.
There are glass break testers available, but I've found I can clap my hands loud and make it register a signal (not strong enough to set it off though unless I'm close to the sensor). I've used this clapping just to test it's wired properly - not to test placement. My sensors are good to 25 ft radius, but sensitivity can be "turned down" to 15ft if desired.
<note: I looked for a link to where I purchased my sensors and they don't seem to carry it anymore. Not sure if they still are made or not. These are very similar. >
There are glass break testers available, but I've found I can clap my hands loud and make it register a signal (not strong enough to set it off though unless I'm close to the sensor). I've used this clapping just to test it's wired properly - not to test placement. My sensors are good to 25 ft radius, but sensitivity can be "turned down" to 15ft if desired.
<note: I looked for a link to where I purchased my sensors and they don't seem to carry it anymore. Not sure if they still are made or not. These are very similar. >