Waterproof DS18B20- Blue Wire??

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ppsieradzki
 
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Waterproof DS18B20- Blue Wire??

Post by ppsieradzki »

Hello,

I bought a Waterproof DS18B20 temp sensor, and am a little befuddled by the wires. I was expecting V+, GND and Signal. But I have Red, Blue, and Yellow wires. Red will be 5V, Yellow is traditionally signal, so I'm guessing there was a goof and Blue is GND?

Just checking before I fry my new thing :)

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ppsieradzki
 
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Re: Waterproof DS18B20- Blue Wire??

Post by ppsieradzki »

Found the answer with some more careful reading: Blue is indeed the ground.

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ppsieradzki
 
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Re: Waterproof DS18B20- Blue Wire??

Post by ppsieradzki »

I do have a question as to the calibration of these things- is there calibration necessary? Or do these come calibrated out-of-the-box? I don't need super-accurate readings, if it's within 3-5 degrees Celcius I'm happy :)

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adafruit_support_mike
 
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Re: Waterproof DS18B20- Blue Wire??

Post by adafruit_support_mike »

The DS18B20 is rated to be within about half a degree of the correct temperature over the range from -10C to +85C.

There's a graph on page 22 of the datasheet that shows the actual performance. The standard deviation of error is about 0.1C, and the device response curve plots a dish-shaped curve with the lowest average error in the 10C to 30C range:

http://www.adafruit.com/datasheets/DS18B20.pdf

You can calibrate the DS18B20 if you want to by comparing its output to a known and trusted thermometer, then subtracting the average difference from the output.

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