Window sensor question


Senior Member
I was curious if there was any reason why the approach below would not work:

The window: Not sure of the terminology, but the window has two moving sections (top and bottom). The lock is in the center where the top and bottom overlap.

Question: If using a wireless sensor, can't I just put the magnet closest to the window and the larger piece on the top of the lower portion of the window?

This way if either part (top or bottom) is moved, the connection is broken and the alarm is triggered. It seems to fit fine, and makes sense, just wasn't sure if I was missing anything.

My other option is to put two recessed sensors in, but I was trying to avoid drilling the window and spending twice as much on the sensors. If there is a reason to go that route (other than the above method allows you to see the sensor) that is another story however.

Any opinions?
Thanks Martin. I went back and tested it again, this time opening the window. The magnet gets dragged with it once the window goes up about a half inch. I might be able to shave it down.

Good to know if it can fit however, that it will work.
I have 11 of the CADDX micro window sensors. The large part is on the lower window ledge while the smaller magnet is on the upper window ledge. There is a small space between the two so that either window can move. No problem when closed or when either window is moved.
Thanks. One thing that occurred to me on these sensor in general (and I have not tested this): There seems to be a reasonable gap before they go off (although it could just be the delay in sending the signal).

Could someone take a magnet and place it near the sensor from the outside to 'keep it closed' and then somehow get the window open? It seems that unless the magnet worked through the frame this would not work, and I assume that someone has thought about this already since these are pretty common.

Noted that the glass would need to be broken to do this, but I was curious if this was a drawback to the window mounted sensors since in many cases they are visible. Of course you also get back to what level of attack you are looking to prevent.

I don't see any problem with your methodology but I'm just wondering that if putting the sensor on the bottom ledge and having the magnet on the lower window bottom part of the frame would be a little more hidden.
Since it is tight when I opened the window (and it dragged the magnet part) and I do not think I can cleanly shave down the plastic (since this will be quite visible), I think you are right.

The visible one does not mount cleanly on the bottom, so I suspect I will go recessed. I just ordered the last remaining sensors needed for all other areas and this is the last one I will have to deal with.