🚀 go-pugleaf

In article <10572@hubcap.clemson.edu> wstef@lowrider.eng.clemson.edu
(W. Gregg Stefancik) writes:
>I am looking for some good fairly inexpensive motion detectors.  I wish
>to use them in and outdoor area as part of an intrusion detection system.

Sitting across from me are three (3 - count 'em) infrared motion detectors
from the in/outdoor "motion sensing" type of floodlight. This particular type
is the Intelectron (TM) model BC 863K.

The whole unit (including mounting plate, waterproof sockets, hardware, soft-
ware (rubber washers, of course ;^), plastic bags and cardboard box) comes
from the local Price Club for $15.99 plus state and municipal cumshaw.

If you hook one up and snoop through the electronics with a voltmeter, you
find that 16VDC seems to be what runs things. If you remove the rectifiers,
filter cap and triac, then hook it up to 12VDC, you'll find that the sensing
circuitry works just fine at that voltage.

Pulling the optoisolater, you can feed the signal into the base of a switch-
ing transistor, put a relay in the collector circuit, and switch whatever you
bloody well please.

I've got three of 'em over there on account of because of the reason is that
I'm building three little motion-sensing space alarms for a local engineering
firm. They'll switch a little security siren from Radio Schlock, the stock 
number 49-489A. Those little buggers run on 6-12VDC, and at 12V, they'll pin
your eardrums together.

I've seen naked motion sensors offered for about forty dollars -- not only is
this cheaper, you get some rectifier diodes, capacitors, optoisolators and
triacs to boot. You may not be able to get a price that friendly on a regular
basis, but if you'll look for sales, you should be able to get 'em below
twenty dollars with little difficulty.

You'll want to do some experimenting. The things are given to falsing when
outdoors, due to waving branches and wandering animals. They usually have a
sensitivity setting, and location can be critical. The blurb in the box will
give you a good idea of the kind of coverage you'll get.

I've observed that they become noticably less sensitive in very hot weather,
but you'd expect that. They will do better at night. Many of them have a
luminance sensor that cuts them OFF in the daytime...watch out for this. The
units I'm using have three time settings, and a TEST setting. In the TEST 
setting, they're on even in daylight, so that's the one I use. Your applica-
tions may vary; likewise your mileage.

Some of you will say: "Haven't you posted stuff about this before?"

Sure. Other people have asked similar questions, too.

Obviously, this isn't the only type of motion sensor around. It's one of the
very best bargains I've seen, however. Additionally, it's damn hard to sneak
up on these things. From the rear, sure, but I mean through the field. If
you have that critical an application, several sensor heads can be combined
for VERY wide-field detection.

Let me know how it works out...I've only worked with this one brand of sensor
(although I've examined another type with a meter), and I'd be interested in
any new information you get. Alsoditionally, I'd like to know if anyone comes
up with a RELIABLE way of sneaking through the field. Everything I've tried
failed, but if there's a way, I WANNA KNOW ABOUT IT. After all, it's MY sec-
urity system, too. I want to know about the holes....

					G'luck,
					    d


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	juice splashing through the air."	-- Mark E. Rogers
   Duke McMullan n5gax nss13429r phon505-255-4642 ee5391aa@hydra.unm.edu