Re: Correct Placement Of IR

["Bob Worthy" <securinc@xxxxxxxxxxxxx>]

"The Pig" <pig@xxxxxxx> wrote in message
news:9%rxg.5001$Mz3.3722@xxxxxxxxxxxxx
> Wondering what the correct placement of IR sensors are.  For isntance,
let's
> say you have a room that is a perfect square, 20 by 20.  Now, the north
wall
> ahs a large window on it and the east wall has a smaller window on it.
>
> Are you suppose to face the the IR sensor in the corner of the south west
> wall pointed at the direction of the two windows or would you face the IR
> detector in the corner of the north west wall facing away.

Actually the Northeast corner with following manufacturers specs on height
from floor. Watch air vents, both feed and return. Don't let the motion look
at reflective items ie mirrors, chandeliers, etc. If all this exists and you
can't get away from it, consider audio discrimination as an alternative.

> I guess what I'm not sure of is are you trying to sense somone entering
the
> window befroe they get all the way in the house or when they have already
> got int he house.

ASAP without creating built in false alarm issues

 I'm not clear on if there are issues facing an IR sensor
> at a window where sunlight might be, someone passing the window on the
> outside might set it off, etc.

By asking this question, you have a pretty clear picture.

> Sorry if this is a stupid question, just now real clear on what the
"right"
> way is.

Most standard detectors have a field of view of approx. +/- 90 degrees. By
placing the detector in the corner, the field of view will be passing in
front of the windows and not looking directly at the windows. You may have
to watch curtain movement when window is open and zone is bypassed for what
ever reason or what air conditioning/heat circulation may do to the
curtains. This field of view will cover what ever the specs are on your
motion. Most motions would cover a 20X20 room in its entirety.