Alarm with open windows

[Bzncrewjr]

We like to keep windows open at night in the summer.

Is there a way to alarm the window screen so the window zone can be disabled and have the screen alarmed. Say if an intruder cut the screen.

 

[tmbrown97]

Yes - search for Security Screens - they can be integrated into your alarm.
 
You can also do two magnets - one in the closed position and one in a set open position - that way if someone slides it more, the alarm triggers.

 

[Del91574]

3 ways.
 
Vent contacts (GRI) allow a certain, albeit limited linear travel
 
Vent magnets, adding a second magnet on the sash, which should be flipped 180 degrees from the standard magnet orientation
 
Security screens, which in actuality should be used in conjunction with window contacts.

 

[patrickjackson]

Bzncrewjr,
 
Magnetic sensors use a very strong magnet. And when the intrusion happens, it is very sensitive to pick up and detect that someone has intruded the normal electricity flow between two magnets.

 

[Del91574]

That's not how a contact and alarm works....nothing flows between magnets and they're really not too sensitive.

 

[video321]

Vent magnets, adding a second magnet on the sash, which should be flipped 180 degrees from the standard magnet orientation

 
DEL-
 
Would you mind explaining the 180 degree part.

 

[Del91574]

Elementary science. Magnets have 2 poles. If you install magnets with enough pull (generally almost anything on the market today, especially those with wider gaps) then if you don't flip the second magnet, you essentially just created a large magnet and the contact could set up and be normal in a position other than the 2 normal positions. The flux lines of the field line up.
 
You flip the poles on the second magnet to be 180 from the first (check the contacts, they always have the like poles on the same side assuming the magnet has some nomenclature or maker's mark on it.
 
This is a huge error that many pros don't consider compared to asthetics of having the lettering face the same way.