
Protecting Buildings: A Late 19th Century Alarm System - sohkamyung
https://blog.library.si.edu/blog/2019/07/23/protecting-buildings-a-late-19th-century-alarm-system/
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segfaultbuserr
[https://en.wikipedia.org/wiki/War_of_the_currents#Safety_con...](https://en.wikipedia.org/wiki/War_of_the_currents#Safety_concerns)

> _The City of New York did not require burying and had little in the way of
> regulation so by the end of 1887 the mishmash of overhead wires for
> telephone, telegraph, fire and burglar alarm systems in Manhattan were now
> mixed with haphazardly strung AC lighting system wires carrying up to 6000
> volts._

So yes, even electrical fire and burglar alarms existed since 1880s.

As a side-node, although "AC is dangerous" has been used as the corporate
propaganda talking point during the Current War, the safety issue of AC (or
mains electricity in general) was very real. Sometimes the AC wires would
short to telephone, telegraph, fire and burglar alarms, and guess what could
go wrong... The solution is proper safety practices and regulations in the
next decade, rather than attacking and boycotting the use of AC.

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whenchamenia
Dc had most of the same issues when shorted. Not sure how ac vs dc plays a big
part here.

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duxup
I always liked the old travel burglar alarms that were effectively a door stop
with a trip point on it that would trigger a small charge that went off like a
gun if someone opened the door while you slept.

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jws
My grandparents had one that was a windup bell with two spikes on the bottom
and one to stick in the hotel door. If the door started to open the bell would
ring. Possibly from the family hotel from the early 1900s.

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Animats
That's a neat little system.

It requires considerable installation, though. That's a big problem. The
brochure says that you have to pay travel expenses if the site is more than 10
miles from their offices in Newark, NJ.

Nest struggles with this. Their thermostat gadgets would be much more useful
if they had a power source and control over some dampers and windows. But that
would require a force of skilled HVAC installers.

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hlieberman
How did it sense fires? I guess heat transference along the steel cables
connected to some kind of... bimetallic strip?

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tdeck
I was assuming the wires would simply burn/melt and go slack.

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hlieberman
I suppose... the fire would have to be pretty intense at that point to soften
steel enough to slacken though. I'd have thought a fully engulfed house fire
would be barely hot enough to do the trick, and by that point, nobody is
putting anything out with a couple of buckets.

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CliffStoll
forget the alarm. I want their fonts!

