"G. Morgan" wrote in message
...
On Mon, 2 Nov 2009 02:45:43 +0000 (UTC), (David Combs)
wrote:


Dig into the thing, disconnect the alarm, and wire
on instead something really LOUD, LOW PITCHED, etc.

To me, that's a pretty good way to go.


It's also against code.

One should NEVER tamper with the insides of a life-safety device. Find
the
right device for the right purpose.

Agreed. Even when I thought my only choice was to hook a louder, lower
frequency sounder to an existing alarm, I was thinking of coupling it with
an audio sensor of some kind triggering a relay when it "heard" the alarm
sound. Since it was his only smoke detector in the room, I wanted to make
sure there was no alteration of the circuit. It's possible to couple the
smoke alarm's output via a mic or in induction pickup like an old suction
cup telephone tap.

The problem I ran into is that I knew that the unit he needed was $300 and
way over budget for a guy who got shown the door at a company he/we helped
build when he got sick.

If the choice was a hacked smoke detector he could actually hear, v. one
that was code approved that he couldn't hear, I would hack. There were some
other options, though, like finding a smoke that closed dry contacts when it
sounded and then hooking a louder sounder to that one.

I am not sure what to do now that I've found out he sits in his chair with
full cup noise-canceling headphones on, often falling asleep. It's time to
step up to a chair shaker. Now here's the "moral" issue. He's already got
two smoke detectors now. One he can actually hear with his high frequency
hearing loss. While it's not code, buying a third detector and somehow
connecting it to a relay to control a bedshaker would mean he was already
overprotected. Since he at least meets minimum standards with two, is
hacking a third to control something I could attach to his chair that would
vibrate it that much of a sin? I've see the little off-center load motors
they use to make cellphones vibrate, so there's got to be some "home
brewable" or even reasonably priced commercial unit out there.

The real problem is that he definitely won't spend the money for any of the
horribly overpriced systems sold commercially. I understand that they mark
that stuff up tremendously to avoid getting whittled to nothing by insurance
reimbursements, but to him it's real money.

The best technical solution may be a wireless mike with a telephone pickup
placed on the alarm. When it sounds, it will be transmitted via the pickup
to the wireless mike receiver. Then, I can use Y-cables to combine the
signal from the alarm into the headphone feed from his stereo/TV console. I
could use a microphone with a very high squelch level to filter out any
noise except the detector. Hmmm. I guess the first thing to do is
research bed shaker smoke alarms. The fun never stops.

Thanks for your input, Mr. Morgan.

--
Bobby G.