Re: Dual Tech motion detectors with dual relay outputs ?

[Marc_F_Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Sat, 25 Aug 2007 18:16:09 -0700, Jim <alarminex@xxxxxxx> wrote in
message  <1188090969.600404.298530@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:

>You didn't ask, but if I were doing this and it were a "home" project,
>I'd be using two "completely different" technologies choosing one each
>from each of the following 3: ..... motion, photo beam and stress
>sensor.
>
>That is, ....... I wouldn't use two from the same technology.

Good point. (although IR and uWave are entirely different technologies --
speaking as a geophysicist ;-) And an since we are making fine distinctions
;-)  I've never much liked the term "stress sensors" as applied here. The
sensors typically used response to _strain_.

Our floors are mostly antique, bare wood (not carpeted)  and getting under
the flooring is an issue. Our house was built in 1821 and I don't like
tearing up the floor boards for what is a short-term (10-15 years ?) for
the whims and  convenience for the current owners  (that would be us ;-).

Using An IR Motion detector as a "wall" as I now plan using the Visonic Spy
4 's is different in some ways from using IR as a 'volumetric' detector.

The main problem with the photo-beam approach is that for our particular
application, it is not-trivial to make it unobtrusive.  A surface-mount
photo-beam at person-height is out of the question on aesthetic grounds.

A valuable suggestion nonetheless that I might be able to integrate.  I
presume that there are unobtrusive ones that I just don't know about. I
have a number of Banner industrial beams and sensors. At least one of the
applications goes past a framed-in closet area where I can get into the
wall easier than into solid brick walls. On the closet side I could have
two small peep holes for the beams. On the brick side, it would be easy
enough to embed a piece of mirror in a hole small enough and deep enough so
that it is dark and not visually obvious. Or ... ?

For a narrow space like a hallway, air pressure sensors might also apply
(with attendant falsing problems). The Brits use these some, but seems
esoteric/unpredictable to me.

Thanks for your continuing suggestions and observations ... Marc

Marc_F_Hult
www.ECOntrol.org