Re: What kind of sensor did I see today?

["Jim" <alarminex@xxxxxxx>]

SecurityNovice wrote:
> Frank,
> Does the intruder break the wire, thus breaking continuity, or is the wire
> pulling on a mechanical trigger when pulled taught?  Is this still a viable
> means even with all the photoelectric sensors on the market for above a
> recessed ceiling say in a bank or high end jewelry store?
>
Lacing wire goes back to the 1800's When Edwin Holmes was doing alarm
installations. Up until about the mid to late 70's, photoelectric beams
were large devices using automobile bayonet style light bulbs,
projecting visible light through a glass lens. They used a lot of power
and the only way standby capability was available was to use a
motorcycle or automobile battery. However, there weren't any small
sized battery chargers so the battery had to be manually charged on a
periodic basis. Therefore, most people didn't have standby batteries,
so during a power failure the alarm would trip. The Ademco 1200 and
1300 I think were the most popular. It wasn't until the Galium Arsnide
(?) elements were developed that allowed a solid state PE device with
an infrared pulsed signal and a much smaller unit with standby
capability.

Other than the uses that have  already been described to you, there was
also a wire called trap wire. This was a thin insulated, flexable,
stranded wire that was used on pull traps. This was called a "live"
trap versus a pull trap that just used a string of some sort, which was
referred to as a "dead" trap. The live trap would trip the alarm if
someone either cut or pulled the trap. The dead trap only worked if the
clip was pulled out. See Ademco number 72 pull trap. I don't think the
UL live traps are made anymore. Sometimes the solid lacing wire was
substituted for the trap wire. Not what it was meant for, but sometimes
you'll find it used for traps too. There was also much wider foil too.
This was used on doors mostly. The wide foil was applied to a piece of
masonite and then the masonite was attached to the inside of the door.

Very occasionally, I'll still use trap wire if I'm doing an old house
with the old fasioned wooden basement windows. Especially if they're
painted closed, nailed shut, etc and the only way in is to break
through the three panes of glass. I just may have the last roll of trap
wire in existance. :-)

The thin wire that was used to construct basswood screens was an
uninsulated bare copper wire. I think I may still have a roll of that
stashed away somewhere too.