[Noisebridge-discuss] Termperature sensor datalogger

[Lee Sonko]

A thermister is probably what you want.

maybe Jameco product 207037
http://tinyurl.com/ydgvzgo

The resistance changes according to a curve so it needs to be massaged a
little. This should do it for you.
http://www.arduino.cc/playground/ComponentLib/Thermistor2
 
If I remember correctly, it's accurate to about +-0.2 degrees.


For the batteries at subzero temperatures... ugh. Buy extra batteries? This
cheap charger works great:
http://lee.org/blog/2008/07/10/vanson-8-aa-nicad-nimh-battery-charger/






> -----Original Message-----
> From: noisebridge-discuss-bounces at lists.noisebridge.net 
> [mailto:noisebridge-discuss-bounces at lists.noisebridge.net] On 
> Behalf Of Glen Jarvis
> Sent: Saturday, April 10, 2010 7:40 PM
> To: Noisebridge Discussion List
> Subject: [Noisebridge-discuss] Termperature sensor datalogger
> 
> I am doing a diy bio experiment on survival rate of e. Coli 
> after freezing (with different cryo agents). I'd like to make 
> a quick arduino data logger.
> 
> I need to measure temperatures around -20 degrees C (about -4 degrees
> F.)
> 
> I did something like this with my Lego mindstoms sometime 
> back - but it was for a very short amount of time.
> 
> I need to take regular measurements (like once every 15 min) 
> for a month.
> 
> Does anyone know a good vendor for a temperature sensor in 
> this range?  
> What are the issues I may encounter operating a battery in 
> sub zero freezing temperatures on an ongoing basis? I don't 
> mind changing out batteries or retrieving device for data 
> retrieval once per day.
> 
> 
> Glen
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