In message , Percy writes
On Thu, 19 Dec 2013, "fred" writ:

In article , Phil writes
Hi. I am in the process of completing a home-brew central heating
controller which will be able to measure the temperature outside of the
house as well as in 3 rooms inside.

Our house faces north/south and I plan to mount the outside sensor just
under the eaves but do I mount it on the northerly side or the
southerly?

Obviously, the northerly side never sees the sun but I am concerned that
the sensor may be affected by stored heat, or should that be cold so,
has anyone got any advice please?

You don't want it to experience any solar gain so put it on the North
side.

Thermistors are low cost sensors and pretty standard in commercial
gear, 10k at 25degC is a typical example that would be fine on a long
line using twisted pair (phone or cat5e). I didn't bother using
shielded cable.

I already have TMP36 remote solid state sensors using STP cable and
they are pretty accurate. Certainly within 0.5C from -20C to +50C on a
5 metre cable. I have had them tested at work. You really must have STP
as any noise messes up the readings as I found out when I tried them
with UTP cable (

A simple IP68 outdoor junction box will be fine for a housing and
sticking the sensor to the lid would give it a low thermal mass with a
response as least as fast as the weather.

Thanks for the suggestion, I hadn't thought of IP68 boxes.

I was about to reply to fred but you got in first. I too, have TMP36
sensors and I'm using the circuit given by the manufacturer which seems
to be wrong. What remote V to I converter are you using?

I also agree that the IP68 box idea is good.
--
Phil