Project: A Cheap, Accurate Thermometer

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tracecom

Joined Apr 16, 2010
3,944
This is a simple little project that results in a useful tool: an accurate thermometer with a remote wired sensor. The thermometer is accurate and very inexpensive.

The project is easy, safe, and suitable for electronics beginners. I previously posted about it on this forum, but did not provide full instructions. After some encouragement, I wrote a detailed procedure, which is attached.

Note that even though the instructions are for a Farenheit thermometer, it could just as easily be built in a Celsius version by substituting an LM35DZ for the LM34DZ.
 

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Georacer

Joined Nov 25, 2009
5,182
Good one! The accuracy is 0.5 degree Celsius as per the datasheet, pretty adequate!
Other useful applications can also be found in it.
 

calvinsmit

Joined Sep 8, 2010
1
I am using this idea as water temp sensor in my Low pressure solar geyser on the roof. Because of the long cable run you HAVE to put a 2k-10k in series of the output leg at the sensor.Compensation for cable run. Also I leave the meter on the milivolt scale and have a 3pole double throw switch on top.When I push it I get my reading.Using one battery for meter and sensor !! A 1000uf cap charges all the time across the battery, untill I push the button and then the battery gets switched to the meter and the cap switched to supply power to the sersor. Wait 1 sec to stabatilze and bingo..
 
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