> I dunno.  1 degree C doesn't seem very accurate to me.  I mean, one
> degree F (5/9 degree C) makes a difference between "comfortable"
> and "too cold" in my home temperature...

I suspect most people would find it hard to detect that sort of 
difference on an absolute basis. As a comparison eg between two rooms 
it would be easier. You must be that most unusual of creatures - a 
sensitive engineer. :-)

> (Does anyone make a sensor specifically aimed at human-range
> temperatures, say 0.1 degree C over the range 10 to 30 C?)

Platinum RTDs probably suffice but are expensive. (100 ohm at ?20C? 
standardised platinum resistors).You could probably "roll your own" 
for less than commercial.

You can do EXTREMELY well with some thermistors, sold expressly for 
this purpose - probably as good as you want.

A gas thermometer can be extremely accurate - but you then need to 
measure other parameters such as pressure.

The two-current method with a silicon diode is cheap, accurate and 
little known. A briefish googling found nothing. / If you successively 
apply two different currents to a diode the difference in voltage 
drops is related to temperature. Within a given family of diodes the 
method is independent of the particular  diode being used.

Anyone else got any information on practical implementations of this 
method?


        Russell McMahon

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