[Noisebridge-discuss] Termperature sensor datalogger

[Glen Jarvis]

Lee,

    This is excellent. Thank you for the help. I don't mind recharging  
batteries often - but will they operate properly for a day, explode,  
cause aliens to visit my home, or anything else weird?

    I don't mind experimenting, but if I get battery acid in the  
freezer, I'll be in Trouble! (with a capital T). I already have petri  
dishes of genetically engineered e. coli in the refrigerator, and am  
about to put small frozen viles in the freezer... oi! :)

Glen

On Apr 10, 2010, at 8:54 PM, "Lee Sonko" <leelist at lee.org> wrote:

> 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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>