h a l f b a k e r yBreakfast of runners-up.
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I'm mainly just sticking this here in case anyone else would benefit from it. I wouldn't regard it as in any way interesting. Use the anti-burglary devices which set off an alarm when the windows on which they are stuck vibrate strongly as "doorbells". Stick them to glass on a front door so that
when someone knocks, it sets off an alarm.
Boring but practical.
Glass Alarm
http://www.allprodu.../kwd/23-ld-26b.html
Not just for breaking glass [csea, Apr 17 2009]
[link]
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I'm pretty sure glassbreaks work based on the sound of breaking glass. Just knocking won't do it, I don't think. |
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It will, i've tried it. It even works with a loud
noise near the glass. |
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Oh, it works, alright! Those damn alarms are always going off in the mall parking garage, set off by the slightest sound. The seem particularly susceptible to the low-frequency bass vibrations that chavs like to pump out of their vehicles. In my neighborhood, the doorbell would never stop ringing. I guess it's a good idea for a quiet neighborhood, though. [+] |
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The one i've used turns itself off after a few seconds. I was wondering about the traffic noise, but it's been OK so far. |
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