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From: ee5391aa@hydra.unm.edu (Duke McMullan n5gax)
Newsgroups: sci.electronics,rec.ham-radio
Subject: Seeing in the dark (sort of)
Message-ID: <1018@ariel.unm.edu>
Date: 25 Nov 89 04:04:08 GMT
Sender: news@ariel.unm.edu
Reply-To: ee5391aa@hydra.unm.edu (Duke McMullan n5gax)
Organization: University of New Mexico, Albuquerque, NM
Lines: 40

Yew electronickers out there take notice -- this might be useful.

Prices on infrared motion-sensor outdoor lights have dropped down to the
$15 (sale) level here in Albuquerque. I picked one up back when they were
stable at $17 (Price Club) and took the controller apart to play with it.

The meter probes showed about 16VDC running around in there, and subsequent
experimentation had the thing working just fine on 12VDC.

Of course, the triac was no longer in the circuit (hard to turn off on DC) and
the 110VAC->16VDC circuitry was bypassed, but placing an LED in place of the
optocoupler made for handy experimentation.

I'm convinced that we have here the basis for a hard-to-defeat (hard-to-de-
tect, even) space alarm. You have to have a unit which has a sense position
that isn't shut down in daylight, but all the ones I've worked with (all two
of them) had that capability.

Replacing that LED with a resistor and the base of an NPN transistor, and put-
ting a 12VDC relay in the collector circuit gives a handy combination: I'm in
the process of mounting that in a box. A modular motion-sensing switch, which
runs on 12VDC and can be moved around quite conveniently, offers possibilities
to me. A sensor for wildlife photography, a coyote scarer, a portable trail or
road "eyeball",...the mind boggles.

I think I'll take it down to the next cavers' regional get-together, and put
it in the camper on my truck, driving a Radio Schlock 49-489 piezo siren.
That's one LOUD siren, folks. Check it out.

Think about it. What would YOU do with such a device? Tell the net. We're
listening....

						Click, click, ZAP!
							  d




            Give the gift that keeps on giving...a female kitten.
     Duke McMullan n5gax nss13429r phon505-255-4642 ee5391aa@hydra.unm.edu


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