2 wire Glass break sensor

I just finished installing some GE 5150-W glass break /pressure seensors on my M1.

They are a nifty little self contained piezo unit that is only 1 1/4 inches square and mounts in the corner of a window with a double stick pad.

In normal operation, it presents a 14 ohm resistence on the zone. When the pressure from a shattered window compresses the case, the piezo crystal inside generates a millivolt current that changes the resistence to the Mega-ohm range for a few seconds then it fades back to nominal 14 ohms again in a couple seconds more.

Even though the specs guaruntee only I Meg of resistnace during operation, I tapped on the cases with a crewdriver handle and the ones I installed shot up around 23 Mega-ohms for a 4 second count.

What is nice about them is that you can series a few sensors with a EOL at the end and the Elk will still see them as a closed contact. The normal Elk tolerance for the 10% varience in the EOL resistor easily masks the individual sensor resistances. No power is consumed from the Elk (except for a miniscule drop across the resisntance I suppose). I set the zone to Eol supervised and it works like a champ.

They are also supposed to have a 10' range for glass breaking through the air, but I haven't tested that function.

So if you need to put a glass break on a 2 wire zone that you can't feed seperate power to, give these little beauties a try.

Automated outlet has them for about $14.00 ea.
I bought one of these to check out, with the idea of mounting it at outlet height (hence being virtually invisible). I have not gotten to the point of testing it or validating that it is ok at that height.


There may be some reasons against it but I have had very little time for cocooning lately (It is a shame, I have a stack of uninstalled equipment at this point).

EDIT: Your price is half that of these, so is nice.