Re: Occupancy Sensors - Bik 'People Detector'

["Andrew Roberts" <andrew@xxxxxxx>]

Occupancy sensing for light triggerring with Comfort is something we get
asked quite regularly, PIR's are just not clever enough at this.
We thought we had the perfect answer when one of our customers discovered
the 'People Detector' at www.bik.com
it costs $50 each if you buy 2 or more, but read on, this is more a topic
for debate than an advert.

quote: The People Detector is a low cost, micro-electronic based device
that
can detect the presence of both moving and stationary objects through solid
materials. Its ability to operate through any non-conductive material
(upholstery, carpets, sheet rock, wood) permits complete invisibility. The
sensor functions by detecting minute changes in an ultra-low-power electric
field generated between two remotely locatable antenna electrodes. Its
range
is adjustable from inches to over 12 feet and can be used to cover an
entire
room.

The product has been tested by one of our installers,  Taybell Alarms in
Leeds with Comfort www.taybell.co.uk and after many experiments they are
getting some mixed/reasonable results in just one of the modes 'Transmit
Mode', but it does involve using insulated aviary wire mesh under the
floors
or carpets and a wire aerial in the ceiling and requires retuning after
furniture is added to the room. The basic principle is that when you are in
the room you are breaking the 'earth' potential between the two aerials.
You
can then add the BIK detectors relay output to a Comfort zone and program
the zone On and Off response which can switch the light on if dark upon
entering(Zone On response), and off after say 5 mins of leaving the room
(Zone OFF response).

It means that you can have the lights reliably switch on and off when the
first and last person enters the room and if you want the lights to stay
OFF
when sleeping in the bedroom, you leave out the mesh under the bed. So you
could even have it so that getting out of bed during 'Night Mode' just
switches the bathroom light on but in other modes switches the Bedroom
light
on, using the get mode action on the zone which has the bik connected. one
drawback is  if you touch a radiator or other earthed appliance, the bik
can
no longer sense you. This can be useful though for the bedroom application
by earthing the bed leg.

They spent days testing the product in the 'Shunt Mode and found it highly
unstable and more sensitive to the room dynamics such as moving furniture
about. Transmit mode has very little documentary information which was
dissapointing as it is the mode which promises better reslts.
Also they have a reveiw of the product which is 2 years old and no updates
have been offered even though the product has been updated last year with
higher sensitivity (17% increase).
http://www.shed.com/articles/TN.proximity.html

I should add this is NOT a recommendation as you WILL experience
difficulties in setting it up and their UK support committment is
uncertain.
BIk haven't replied to Taybell's emails or their message left on their
answerphone, but it may offer some answers for the difficult area of
occupancy sensing. If anyone knows any other occupancy detectors, please
let
us know.

Andrew Roberts
Comfort Home Controls
(Tel: 44(0)1244 680675)
(Fax:44(0)1244 671455)
WebSite: http://www.comfort.org.uk


----- Original Message -----
From: Nigel Orr <Nigel.Orr@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: 23 June 2000 08:55
Subject: RE: [ukha_d] Occupancy Sensors and No Light Switches


> At 17:35 22/06/00 +0100, you wrote:
> >levels, whether you've just come in from outside etc. etc. A
discreet
button
> >somewhere to say "It is now dark" and "It is now
light" is perhaps a good
> >idea.
>
> It's surprising how 'relative' sense of light and dark are- it's a bit
like
> heating, and is one of the things which makes 'proper' automation
trickier
> than it looks... perception of sound seems to be quite well researched
and
> understood, so it's easy to model, but heat and light seem to be
tricky!
>
> >enough. I found that standard alarm sensors tend not to be - they
are
> >usually positioned to be most sensitive to intruders coming
through
windows
> >etc, not people walking through internal doors.
>
> The usual positioning is 'not pointing at a window' and 'set so that a
person
> entering by a door or window will be walking across the sensor's
view'.
In
> my case, that almost always positions them so that when you open a
door
> into the room, it blocks the sensor until you walk further into the
room,
> so it would have too much of a delay to be usable for automatic light
> switching.
>
> The only way I can think of to solve the problem is to have a separate
HA
> sensor, positioned so it gets someone entering by the internal door
> immediately.  But that means more 'zones', though the sensor wouldn't
have
> to be as high quality as standard alarm sensors, as the penalty for
'false
> alarms' is much less.
>
> >Knowing when to switch off
> >lights is much harder.
>
> My best guess for 'room empty' would be when the power consumption
drops
to
> near zero... eg TVs, reading lamps etc go off.  If you think about it,
> there aren't _many_ occasions (there are some) when you sit in a room
with
> no electrical appliances turned on.  But there's still a need for some
sort
> of manual override, and it does need you to have manual control over
the
> other appliances, which isn't very sophisticated!
>
> Personally, I can't see myself removing lightswitches for 10-20 years,
if
> the house is ever to be sold, or even if it's just to be 'easy to use'
for
> visitors, they've got to stay- it's surprisingly disorientating if you
> reach for a lightswitch and it isn't just where you'd expect it-
especially
> if you are in an unfamiliar place.  Any automatic system will have to
be
> over-ridden by manual lightswitches.
>
> >  A person sitting still is invisible to most sensors I
> >could think of.
>
> I think Keith posted a while back about a more sophisticated one-
basically
> an IR-sensitive camera with some image processing to decide if 'heat
blobs'
> were human.  It should be something that can easily get cheaper, maybe
in
5
> years.
>
> I know from image processing I've done that it's possible to make a
_very_
> sensitive movement detector, just using a standard CCD camera, without
> _too_ much intelligence, but it does still need a PC per camera (it
was
> written in a lunchtime, so it could definitely get more efficient!)
>
> Actually, on that topic, I was thinking about the 'detecting movement
with
> an outdoor camera' thing that was discussed a few weeks ago, it might
work
> reliably if you have a light sensor and _only_ look for movement
between
> frames if the overall light level doesn't change.  That should avoid
> effects of the sun coming out from a cloud etc, and should be fairly
easy
> to implement.
>
>  > Another problem is that X10 isn't a reliable transmission
protocol.
Signals
> >sometimes go missing, which is also annoying 'cos the lights don't
come
on.
>
> So don't use X10- get some wires in! :-)
>
> Nigel
>
>
>
------------------------------------------------------------------------
> Click here for a chance to win airfare to Vegas for you and 20
friends,
> $15,000 and a suite at Bellagio for New Year's from Expedia.com. Or
> win 2 roundtrip tickets anywhere in the U.S. given away daily.
> http://click.egroups.com/1/5296/9/_/2065/_/961746982/
>
------------------------------------------------------------------------
>
>


------------------------------------------------------------------------
Accurate impartial advice on everything from laptops to table saws.
http://click.egroups.com/1/4634/9/_/2065/_/961757904/
------------------------------------------------------------------------