Novel intruder sensor for windows

[bernardgreen]

When the curtains are closed a magnet in one curtain adheres to metal containing a reed contact in the other curtain. Thin cable in the hem of the curtain provides the connection.

It requires a more powerful than normal magnet and some iron or steel to provide a substantial area for the magnet to adhere to and keep the curtains closed until an intruder pushes them aside to enter the house.

Provided the reed is not magnetically shunted by the metal it will operate normally.

 

[Boilerman2]

too much room for error for my liking also the intruder will have effected a break in before alarm activation!

give me a viper on the window any time!!

 

[seasickstevie]

I'm assuming that Bernard's idea is for when the window is left a bit open for ventilation.
Not a bad idea for programming to internal sounder only for when occupied.

 

[bernardgreen]

It is to detect entry through a large bay window which has 4 sectionswith stone columns between them making effectively 4 separate windows.

 

[TicklyT]

What will happen on a breezy day when a draft momentarily blows the curtains aside?

 

[bernardgreen]

What will happen on a breezy day when a draft momentarily blows the curtains aside?

The trials are with a strong magnet and heavy brocade curtains and even with a small window open the "clasp" of magnet to plate has not been separated.

There is more work to be done but the idea looks to have a future.

 

[bernardgreen]

The trials have mixed results.

Best suited to heavy materials such as brocade where it is much easier to conceal the magnets, switches and cable in the hems.

The sides of the curtains need to be fixed to the walls at the side of the windows other wise the intruder need not open the gap and trip the sensor.

Other than going to floor level and crawling under the curtain it is ( apparently ) impossible to get through the curtains without breaking at least on of the four magnet clasps and thus triggering an alarm.

For light weight curtains the idea has mutated into using magnetic connectors instead of magnets and reed switches. These are short leads with magnets at the end which stick but are not locked together and close the circuit.

One source is http://www.tts-group.co.uk/shops/tts/Products/PD1726386/Magnetic-Connector-Leads/

 

[Jibbeh]

I'm out.