Re: Occupation sensor that works with people sitting still?

["Bill Kearney" <wkearney-99@hot-mail-com>]

> I am searching for an occupation sensor to control lighting that can
> sense occupation even if the person is remaining still (watching TV in
> bed, sitting behind a computer).
> Are there any solutions for this application?

Much like the Holy Grail, people have been seeking for this for ages.
There's no one good way to detect occupancy.

Most sensor systems are setup so they only detect changes over a short
period of time.  Otherwise you'd have to reset the things any time you moved
furniture.  Even something simple like moving an ottoman from one place to
another would require resetting the baseline profile.  So you can imagine
that being less than ideal.

What's necessary is a combination of signals.  There's nothing currently on
the market that bundles it all up into a single "solution".

Our new TV has an idle sensor.  If it hasn't seen an IR commands over an
extended period it pops up a message indicating automatic shut off.  If
we've fallen asleep and don't see the message it automatically turns itself
off.  I worked in an office that at 10pm would blink the lights twice.  If
you were still in the office and wanted the lights to remain on you had to
manually toggle the wall switch.  Otherwise it'd automatically shut them
off.

Passively detecting occupancy is a very hard problem.  Tying it to detected
activity is a lot easier, but certainly not 'simple'.

-Bill Kearney