Re: Placing DS1820's

["Simon Coates" <ecolume@xxxxxxxxxxxxxxx>]

Paul,

I've wired for my DS1820 sensors throughout the house at light switch
height - this is the best place to put them.  Room positioning can be a bit
of a problem though.  This is the criteria I used when planning:-

Don't put them:
- near you heat source
- where the Sun can shine on them and give false readings
- near doorways as draughts will be a problem
- directly above where table lamps will be placed

It's sometimes very difficult to find a suitable position that meets the
above criteria and that also looks aesthetically right, as well as avoiding
high pieces of furniture.

I made a small PCB to mount my sensors.  The PCB also houses a terminal
block and signal diode with jumper select.  I also used a clip-on
transistor heatsink to provide a small amount of latency which will help
minimise frequent switching cycles.  I think it's better to add latency to
the sensor rather than account for it in your control software.  This will
also allow a smaller switching hysteresis.  Experiment with a sensor, you
might be surprised how quickly it responds to changes in temperature - it's
very sensitive because it's got minimal heat capacity.

Don't forget to allow for an externally mounted sensor, or 2 sensors if
your house is large.  That way you can programme for external temperature
compensation into your software.  This will be especially important as you
mentioned that you want to control both heating and cooling to your rooms.

Also, I've wired for PIR occupancy detectors in each room so that each room
can have 3 temperature settings.  A 'normal' temperature for an occupied
room, a setback temperature for an unoccupied room and a lower setback
temperature for an unoccupied house.  This should help lower your heating
costs.


Regards


Simon










----- Original Message -----
From: Paul Smith <ukha@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: 19 February 2004 11:04
Subject: [ukha_d] Placing DS1820's


> Hi Guys,
>
> I'm shortly going to be putting DS1820 (1-wire temp sensors) in each
> room of the house.
>
> The grand plan is to automate the heating and cooling of each room.
> So that I can set a desired temp and the system does the rest.
>
> What I am wondering is does it matter where in the room the sensors
> are. I'm planning to mount them in the ceiling in a discreet vented
box. But
> just want to check that this would be ok.
>
> I know heat rises and therefore the temp at ceiling is going to be
> higher than at body height, so I think I can just compensate for this
> change.
>
>
> The current plan is this.
>
> DS1820 in each room wired back to a TOM10 with autom8it plug-in
> (Available Soon)
>
> Then a set of relays driven by autom8it (again in the pipeline)
> which operate valves, hidden in the floor, by each rad.
>
> Also there will be X10 control of floor standing AC units where
available.
>
>
> Regards,
>
> Paul,
>
>
>
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