Re: Sat on a Toilet Sensor ?

["Karam Karam" <kzkaram@xxxxxxxxxxx>]

If you're talking about the GP2D12 then let me explain that this is=20
not a PIR sensor - its an active IR sensor (emits modulated IR and=20
then detects where reflection lands on linear CCD array to work out=20
distance or 'within range'). The idea would not be to mount it in=20
bowl but perhaps as suggested behind seat pointing downwards (and=20
clearing top of open lid). It may even be feasible to mount in=20
ceiling above head. The relatively small range is probably an=20
adavantage when mounted behind sta person to prevent false triggering=20
but I think that the range can be tweaked to over 1 meter.

You might be able to use a standard timed output PIR sensor mounted=20
in the ceiling with suitably 'adjusted' field of view such that it=20
avoided detecting much beyond the toilet seat. Certainly 'spot' type=20
PIR sensors exist but not seen these in off the shelf (eg. B&Q) type=20
units.

I think that I'd agree that perhaps some sort of load sensor might be=20
more reliable, the trouble is the amount of electronics that you may=20
have to use beyond the sensor itself. A strain guage needs some=20
decent amplification/conditioning electronics and where would you=20
bond the sensor?. A load cell (typically strain guage already bonded=20
to suitable structure) would be placed presumably between tolet seat=20
and floor but as far as I can remember these are quite expensive=20
devices and will still need the final electronics too.

Karam


--- In ukha_d@xxxxxxx, "Marcus Warrington"=20
<marcus.warrington@...> wrote:
>
> I tend to agree with you Ian.. that's why I think something like a=20
strain gauge or load cell is a better solution, since its not=20
connected to the toilet itself, can be completely invisible and only=20
activate upon sitting (well I suppose you could stand on the toilet).
>=20
>=20=20
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> Looking in RS (www.rswww.com <http://www.rswww.com/> ) part number=20
632-124 is a "Mild Steel foil strain gauage, 2mm gauage" cost
=A35.09=20
each
>=20
> Since the toilet is wall mounted with bolts through a 18mm MDF=20
panel, wonder if one of these mounted on the wooden panel would=20
detect any slight deflection of the panel when someone sat on the=20
toilet ?
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> Marcus=20
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> ________________________________
>=20
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On=20
Behalf Of ian.bird@...
> Sent: 13 July 2007 12:37
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] Sat on a Toilet Sensor ?
>=20
>=20=20
>=20
> The PIR detection distance on those mentioned sensors is quite=20
short. For=20
> some it may even be a problem where the person leans forward=20
reading or=20
> dozing - or maybe passed out ;-)
>=20
> I would strongly advocate against putting anything in the pan or if=20
you=20
> can avoid it even under the seat rests. Think of cleaning and=20
possible=20
> water ingress. I have a level sensor in the outside sewage drain in=20
case=20
> of blockage and sorting that out when it fails is a pretty=20
miserable task=20
> :-(
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> Thanks
>=20
> Ian
>=20
> "Marcus Warrington" <marcus.warrington@...=20
<mailto:marcus.warrington%40mis-es.com>
>=20
> Sent by: ukha_d@xxxxxxx <mailto:ukha_d%40yahoogroups.com>=20
> 13/07/2007 12:16
> Please respond to
> ukha_d@xxxxxxx <mailto:ukha_d%40yahoogroups.com>=20
>=20
> To
> <ukha_d@xxxxxxx <mailto:ukha_d%40yahoogroups.com>
>
> cc
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> Subject
> RE: [ukha_d] Sat on a Toilet Sensor ?
>=20
> .. what happens with the loo seat is closed and the PIR detects=20
someone
> in the room.
>=20
> Also the idea of mounting electronics in the bowl itself just seems
> wrong to me.. especially in a country where I can't even have a=20
light
> switch in the bathroom itself.
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> Marcus=20
>=20
> [Non-text portions of this message have been removed]
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