Occupancy detection

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

I came across the following article recently and began to wonder about the
current state of occupancy detection.  Even X-10 at its smartest is pretty
dumb when it comes to turning out lights that you're not really using and
conversely NOT turning out lights that your ARE using (i.e. longer than
average bathroom stays.)   The article got me to thinking about how dogs do
"occupancy detection" and where AI could play an important part of light
control, conservation and "wellness detection" for want of a better term.

***************************************************************
http://wtop.com/?nid=106&sid=1169767

Can Motion Sensors Predict Dementia?
June 18, 2007 - 4:15pm

By LAURAN NEERGAARD
AP Medical Writer

WASHINGTON (AP) - Tiny motion sensors are attached to the walls, doorways
and even the refrigerator of Elaine Bloomquist's home, tracking the
seemingly healthy 86-year-old's daily activity . . . to see if
round-the-clock tracking of
elderly people's movements can provide early clues of impending Alzheimer's
disease. . . . The theory is that as Alzheimer's begins destroying brain
cells,
signals to nerves may become inconsistent _ like static on a radio _ well
before memories become irretrievable. One day, signals to walk fire fine.
The next, those signals are fuzzy and people hesitate, creating wildly
varying activity patterns.


***************************************************************

I recently took a tumble down a stairway controlled by an X-10 Hawkeye
(OUCH!).  As a result, I've come to the conclusion that X-10's motion
detectors, while useful in some situations and for some people, are not
making the cut when it comes to my house.  Ironically, the fall occurred
because I was moving very quickly and did not trigger the Hawkeye, which,
until I fell, had never failed to turn on that particular light reliably.
It's a lot to ask of an HA system to be able to record and analyze speed of
travel and travel patterns within a house, but that article made me think we
might finally be there, equipment and software-wise.   The dog sure knew I
was heading down the stairs at a fast clip, but the HA system did not.  It
could have known, though.

Part of the problem with X-10 RF is wire lathing in all the walls blocking
radio reception.  But I suspect another part of the problem is the growing
saturation of the RF band used by the HawkEye/EagleEyes.  I tested reception
in my house five years ago and where I was reaching 15' between test points
in the past, I now only reach 10'.  While I'm aware there could be a number
of possible causes, the bottom line is that RF-based motion detector signal
propagation is not reliable, particularly in dangerous areas like dark
stairwells.

I've decided instead to investigate the feasibility of using multiple
sensors, and incorporating IR light beams across doorway openings to
positively detect when someone has entered or exited a room.  I've had some
success with pressure mats under carpeted areas, but the places that most
need automatic light control have concrete, tile or wood floors.  If the
sensors and light sources are small enough, I could embed them in the door
trim pretty easily.

I've come across an interesting candidate at:

http://www.apogeekits.com/ir_light_barrier_mk120.htm

and the price per doorway seems to be right but I have a few concerns.  The
first is whether I can mount the diodes and detectors remotely on a 10'
length of wire without affecting circuit values adversely.  The second, more
important question is whether putting IR emitters in all the doorways is
going to cause more problems for the Powermid and other IR communication
devices.  The third is whether I can run all the kits from a master power
supply without interaction issues.

The second half of this equation is what sort of controller is best suited
to handling the demands of multiple-sensor, very high reliability occupancy
detection?  We've discussed this here before, but with WiFi-enabled cell
phones and other new, miniaturized wireless devices becoming available, it
may finally be possible to tell where every member of the household is, 24
by 7.  While it sounds intrusive, think about how much greater the degree of
control there would be over personalized automation if the HA system could
know who was where, and what they were doing.

If they are sitting quietly watching TV, no sudden light flashes.  If
someone's taking a super-long shower or "other" activity, no sudden
darkness.  The system would be able to respond to rules like "if no motion
is detected *but* no one has left the bathroom, leave the light on."  This
one ability would shoot SAF (and my own AF) up considerably and it should be
doable unless someone climbs out the bathroom window.  Turning off lights as
soon as rooms became empty (instead of after X minutes) and being able to
provide "light pathways" as a person walks along through a darkened house
should shave some serious $ off the electric bill.

If FPS games can track hundreds of actors across multiple continents in huge
simulated terrains the CPU horsepower is obviously available to track two
slow moving people and two somewhat livelier little dogs in a rather small
residence!

Any thoughts or relevant information will be appreciated.

--
Bobby G.