Re: Pir Probe update

["David Amphlett" <dave_yahoo@xxxxxxxxxxxx>]

This is going to sound daft, but bear with me. Looking at Stuarts
question yesterday about snow sensors, and then looking into parking
detectors got me thinking about occupancy detection...

PIR's are great unless people sit down (in lounges at least). Well
how about ultrasonic distance measure above seats. Sounds awful
doesn't it, but if it was either spot focused for an armchair (say
1ft circle) or focused to a line (for a settee).

Prime it to the 'empty' chair. Then when blocked above a certain
height it triggers.

Pros:
small and simple installation
cheap
easier than building a pressure pad into the seats!

Cons:
useless if you move your furniture often (maybe make it directional?)
totally screwed if you put a box or pile of clothing on the chair

Note: could also work if mounted behind a seat pointing at where your
head would be!

--- In ukha_d@xxxxxxx, "Frank Mc Alinden" <fmcalind@b...>
wrote:
> Hi All
>         Just a little update on my pir probe......Up till now i have
> referred to it as a occupancy sensor when in fact its a Vacany
sensor
> ;-)....
>
> Have got the pir head mounted in one of my video probe boxes and
have
> decided to put the timing electronics in a seperate box...Also
decided to
> use a pic micro to do the timing...This has got me thinking about
having
> several different sensing heads connected to the Vacany Sensor
box.....
>
>  Have got the pir sensor triggering the Vacany Timer and the idea
is to keep
> retriggering this timer which will time out after 5
minutes.....Homevision
> will poll the vacany sensor (via my Probe hub kit) every 5 minutes
and if
> off will decrement a variable till its zero and turn off lites......
>
> Next Sensor head to add to the Vacancy Sensor is an infrared
receiver...This
> will also retrigger the timer if any ir is received......Which i
hope will
> cover the situation were someone is not moving around but using the
> remote....
>
> Any ideas for other sensing heads ????
>
> More Soon
> Frank
>
>
>
>
>
> www.armaghelectrical.com.au