cancel
Showing results for 
Search instead for 
Did you mean: 

Intruder alarm

Community Veteran
Posts: 26,373
Thanks: 630
Fixes: 8
Registered: 10-04-2007

Intruder alarm

Does anyone know of an audible alarm device that can be used on a bedroom fanlight which is always open slightly at night to let in fresh air? I want something that would sound if it was pulled open enough to reach inside to try and open one of the side windows. The point is (a) to wake us up if someone attempts to get in and (b) to scare the burglar off.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)
5 REPLIES
Community Veteran
Posts: 16,825
Thanks: 1,115
Fixes: 13
Registered: 06-11-2007

Re: Intruder alarm

Mechanical.................... a piece of string securely attached to the skylight. passing through necessary fixings (screw eye hooks) to a piece of hardboard about 6 " square, standing on a cupoard or wardrobe top, with an "unstable" china water jug, (full of noise making items, )
when the window opens, the string activates the unstable jug of noisy items, which fall on the floor, thus waking the occupants, who shout very loudly, and theburglar gets frightened off.... (remember to re-set before going back to sleep !)  Cheesy
electrical.... fix a "microswitch" to the half open window, connect this in a battery powered circuit, so that when the window opens, it sets off the loud bell or siren. thus scaring off the burglar, and the occupants of the building..... (again ... reset before going back to sleep !)  Cheesy
Sweet dreams !  Wink
Community Veteran
Posts: 26,373
Thanks: 630
Fixes: 8
Registered: 10-04-2007

Re: Intruder alarm

I've been thinking about the mechanical approach using fishing line so that it's not immediately visible and therefore circumvented. I didn't really want to start making permanent holes in the double glazing for fixing eyelets etc. so how I could achieve what I want without distorting the net curtains is puzzling me at the moment.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: Intruder alarm

you can get close proximity IR or heat alarms from lots of places, they are non contact and be mains or battery powered, try any DIY or Maplins
http://www.maplin.co.uk/module.aspx?moduleno=223593 use the bulb feed to sound a bell or buzzer
Community Veteran
Posts: 16,825
Thanks: 1,115
Fixes: 13
Registered: 06-11-2007

Re: Intruder alarm

To fix to the "double glazing" frame, you could use  a small piece of "outer" from some suitable cable (telephone) which is fixed to the frame using glue, or a "bridge" of gaffa tape/selotape/carpet tape. then tie the fishing line through the "outer".... use similar approach to routing the fishing line through small pieces of "outer"  (like tunnels) until you reach the required destination....
If using the microswitch version, you could attach it with a "double sided sticky pad". found in many DIY stores, and route the wires in a similar manner to the mechanical version !. by placing the microswitch closest to the "hinge" of the skylight, it will not be obvious to "passers by" ! ! ! ...and so the wiring can be just as discrete. !  Wink
jmd
Grafter
Posts: 2,933
Thanks: 2
Registered: 30-07-2007

Re: Intruder alarm

How about this
http://www.rnid.org.uk/shop/products/alerting_devices/flashingdoorbeacon.htm
the flashing light would distrurb burglar and hopefully you?