Re: Window Bugs

[robertlbass@xxxxxxxxxxx]

>> I would recommend installing them in your trash can...

Actually, the above is correct.  Those are about the most unreliable,
false alarm prone detectors ever to grace the alarm industry.  If
they're the ones I think (similar to the image another poster
suggested), they consist of a bent tube with a small globule of mercury
in it and a pair of electrodes at one end.  The sensor is supposed to
detect impact by disturbing the mercury which briefly either opens or
closes (depending on which way you turn the device) the circuit,
triggering the alarm.

There are several weaknesses to these devices.  For one, mercury has a
hefty expansion coefficient which causes the globule to become larger
or smaller during temperature changes.  This can cause the detector to
become over-sensitive (in the more common closed circuit mode) when the
glass cools down and, conversely, insensitive when it warms up.

Another problem is that windows can vibrate during wind and even when
large vehicles drive past.  Because the window bugs are sensitive to
vibration, non-alarm stimuli can trip them, especially when there's a
temperature drop.

Also, the sensors are easily "adjusted" by turning them on their base.
A single small screw holds the sensor head to the base.  It's very easy
to bump the detector, causing it to become over-sensitive or (perhaps
worse) insensitive to an actual break.

Due to the high incidence of false alarms and the ease with which they
can be tampered, these detectors have not been popular with installers
for quite a few years.  As the fellow using th alias, Nomen..." said,
toss them in the trash.

Regards,
Robert L Bass
Bass Home Electronics
The DIY Alarm & Home Automation Store
www.BassBurglarAlarms.com