From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: Presence detector.
Date: Sun, 15 Sep 2002 15:25:01 GMT
NNTP-Posting-Date: Sun, 15 Sep 2002 08:25:01 PDT
"N. Thornton" wrote:
> "Popeye" wrote in message news:...
> > use a counter to monitor the number of people in the room. Use two
> > parallel beams in the door way. so entry and exit can be distinguished. Use
> > an up/down counter. Up count for entry and down count for exit. if no. of
> > persons =0, turn off the light using a relay. simple enuff?
> Thats just asking for trouble. You really think the kids arent going
> to mess with it? They'll put 50 'people' in that room, and the silly
> tronic counter will know no better. If you do use an imperfect
> detection system, put a ngihtlight in there too, so when the light
> goes out people can still see. It'd be dangerous otherwise, in a
> bathroom or stairs, or kitchen, or garage...
> A big pressure mat on the floor is another option, but wouldnt cover
> the bath. A capacitive sensor mat would do it, plus ditto taped to the
> underside of the bath (marine tape please).
> Its one of those simple jobs that isn't simple.
> Regards, NT
Personally, I like the motion detector method. If I fall asleep in a
room, the light goes out. Unfortunately, it doesn't work well in
meetings. I fall asleep and the light stays on because some oaf is
blathering and waving about.
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons firstname.lastname@example.org