Re: Re: HA Holy Grail #1: Occupancy Detection

["Michael" <michaelhims@xxxxxxxxxxxxxxxx>]

Kim,

I was refering to using them alone (as I thought that is how the OP was
referring to using them). But yeah I agree they can be useful when used
with other devices such as the PIR sensors

Michael
----- Original Message -----
From: Kim Wall
To: ukha_d@xxxxxxx
Sent: Wednesday, August 23, 2006 10:14 PM
Subject: Re: [ukha_d] Re: HA Holy Grail #1: Occupancy Detection


Michael wrote:
> Reed switches would only work if the door opened/closed - won't work
> if the door was open to start with, and how do you work out if
> someone if going in/out?

I've thought about this before, as it strikes me that reed switches are
a cheap and moderately useful way to supplement PIRs or other occupancy
detection, assuming there's some logic involved.

eg. if a room has all doors closed and no PIR activity for n minutes,
then it can be assumed to be unoccupied, so any door opening implies the
room is now occupied.

If a room has all doors closed, and the PIR activity stops, it's still
occupied, because people aren't usually in the habit of climbing out the
window.

If it's a bathroom, and you're in the habit of leaving bathroom doors
ajar, you can assume that door closed implies occupied.

If it's a small storage room, door open implies occupied.

And so on... It doesn't cover everything, but if it's relatively easy
to do, then it may be worthwhile. Assuming you don't have
cats/dogs/roombas/children/an open-plan American upbringing[1].

I also wonder whether a bit of logic can improve things with just PIRs:
eg. if there's no motion from the living room, but there hasn't been any
in either adjoining room, then the living room is still occupied.

Kim.

[1] A friend of mine, who's originally from New York and now lives in
Sheffield, finds the ubiquitous 2-up-2-down terraced houses excessively
claustrophobic. She has removed the doors from some of the rooms in an
attempt to improve this, and now wonders why the house is so cold...




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