Re: Occupancy detection

["Robert L Bass" <RobertLBass@xxxxxxxxxxx>]

> I'm glad to see this getting attention, because
> motion activation of lights is definitely on the
> top of my list of things i'm not happy w/
> about my automation installation...

There are newer motion detectors which make
this easier and with a better WAF rating. Visonic
makes SOY series motion detectors which are
very small.  The electronics are in a tiny cylinder
which slips into a hole in the wall.  The "eye" is
a small, round head about 3/4" diameter.  The
detector can be ceiling or wall mounted, just
inside the door to a room.  If there is only one
door to the room it is possible to use two
detectors -- one inside and one outside to count
occupants.  That's a somewhat imprecise science
but it can be made to work, especially if there are
not a lot of people coming and going at the same
time.

There are several models (SPY1, SPY2, SPY3
and SPY4) with different detection patterns.  I
have DIY customers using them to control lights,
HVAC, etc.  In one application a "curtain" pattern
detects movement through a narrow plane of
detection.  The detector was turned 90º to make
a layer of coverage about 2.5' above the floor.
This is high enough to ignore the dogs but will
trigger if a person the room.

> Add to that the delay of the detector picking you
> up once you are in range, sending the signal...

Most hard-wired detectors can be set to respond
in the first 1 or 2 footsteps into the protected area.
Also, when automating little used rooms such as a
pantry or closet, you can use simple magnetic
sensors (called a "contacts" in the security trade)
to detect the door being opened.  These respond
instantaneously.

> I relay through the PC so i can do more macro
> control such as only turning on lights when it's
> after dark).

That will add latency, no matter what kind of
detectors you use.  Have you considered a PC-
connected system with separate, stand-alone alarm
/ automation controller?

--

Regards,
Robert L Bass

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