[s-cars] Interior temp sensor source

[Kevin Day]

Room temp. here is definitely closer to 22C than 15C.  However, it's my
understanding that thermistor curves are not standardized the way e.g.
thermocouple curves are.  But for this application it may be moot.

Here's an interesting page describing how one can determine a very
close approximation to the curve using three data points:
http://www.betatherm.com/stein.htm

In practice though, I'd probably just buy Digi-Key p/n KC004E-ND and
give it a try.  It looks to have nearly identical physical dimensions
and is a 3K NTC.

-Kevin

On Sat, Nov 13, 2004 at 11:05:50AM -0500, Mark Strangways wrote:
> There are 2 different sensors listed, one is a 3k NTC, which would show 
> Kevin's room to be 22 C.
> The other is a 2.25K NTC which would show his room as about 15 C
> 
> So I think it is save to say it's a 3k NTC
> 
> Mark
> ----- Original Message ----- 
> From: "Mark Strangways" <Strangconst at rogers.com>
> To: "Kevin Day" <kday at ultrameta.org>; <s-car-list at audifans.com>
> Sent: Saturday, November 13, 2004 10:48 AM
> Subject: Re: [s-cars] Interior temp sensor source
> 
> 
> >Kevin try to get a reading of the resistance at 25 Celsius.
> >Mark S
> >----- Original Message ----- 
> >From: "Kevin Day" <kday at ultrameta.org>
> >To: <s-car-list at audifans.com>
> >Sent: Saturday, November 13, 2004 10:10 AM
> >Subject: Re: [s-cars] Interior temp sensor source
> >
> >
> >>At least on my '94, there is what is clearly a thermistor
> >>mounted behind the little grille in the sunroof control panel.
> >>
> >>Tony, since I happen to have a sunroof control panel sitting on my desk
> >>here, FYI it is a NTC (negative temperature coefficient) thermistor, and
> >>measures approximately 3500 ohms at room temperature.  You very likely
> >>could replace this with a standard thermistor costing pennies, once the
> >>thermistor parameters are known.  If you want to go this route I can dig
> >>up a thermometer and measure a few points on the resistance vs.
> >>temperature curve for you.
> >>
> >>I think the microphone is in the A-pillar, but haven't yet needed to
> >>take that part of the car apart...
> >>
> >>-Kevin
> >>
> >>On Sat, Nov 13, 2004 at 12:02:35AM -0700, Bob DG wrote:
> >>>Isn't that the microphone for the hands free phone? I thought the temp
> >>>sensor was in the dash somewhere?
> >>>
> >>>>From: "Tony" <tony.curran at sympatico.ca>
> >>>>To: <S-CAR-List at audifans.com>
> >>>>Subject: [s-cars] Interior temp sensor source
> >>>>Date: Fri, 12 Nov 2004 18:30:08 -0800
> >>>>
> >>>>Guys,
> >>>>
> >>>>Looking for a source for the interior temp sensor in the sunroof 
> >>>>control
> >>>>panel. Local dealer has them for cdn$80. Are there any suppliers out 
> >>>>there
> >>>>that carry them.
> >>>>
> >>>>TIA
> >>>>
> >>>>Tony
> >>>>_______________________________________________
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> >>>>S-CAR-List at audifans.com
> >>>>http://www.audifans.com/mailman/listinfo/s-car-list
> >>>
> >>>
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> >
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