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Florida
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Hello,

I just bought a temperature probe and I need some help. Does anybody know if it is a 5v or 3.3v sensor and which wire is positive and which wire do I attach into my analog port on the Arduino. Both of the wires are black, but one as a grey stripe on it.

Thanks,
Drew

http://media.digikey.com/pdf/Data%20Sheets/U.S.Sensors/USP10979.pdf
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One of the wires is perhaps shielded against electric noise.
But I don't know which one.

It is a NTC resistor of 10k at 25 degrees Celsius, maximum 105 degrees Celsius.

You have to find some examples how to connect it, and how to calculate the temperature.
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Florida
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I have looked all over for examples and I can't find any. I can calculate the temperature by using a thermometer and comparing what the probe values are vs the temperature, but I don't know how to connect the probe to the Arduino.


Any ideas?

Thanks,
Drew
« Last Edit: January 20, 2013, 04:32:44 pm by Drew Davis » Logged

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You can try this schematic.
The R5 resistor can be adjusted to get the voltage you want at the temperature you want.


* Therm.jpg (116.72 KB, 534x496 - viewed 52 times.)
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The way you have it in your schematic isn't the same as how you have it wired up!

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Some add a capacitor to eliminate noise.

Simple example:
http://playground.arduino.cc//Main/Kty81-110

Extended library:
http://playground.arduino.cc//ComponentLib/Thermistor4
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Florida
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Wow! This is a lot more complicated then I thought.

LarryD: On your schematic what is "Arduino 0v" and "RT1"? (I'v never really used a schematic before)

Krodal: Where would I put the capacitor in LarryD's schematic?

Also I don't have an R5 resistor and I would like to get this working ASAP. Could I use a 10K Ohm resistor for now?


Thanks!!!
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Quote
LarryD: On your schematic what is "Arduino 0v" and "RT1"? (I'v never really used a schematic before)
This is the GND pin, found on the Power header on your Arduino board
Put a .1uF capacitor Across the Thermistor (RT1, your temperature sensor)
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Also I don't have an R5 resistor and I would like to get this working ASAP. Could I use a 10K Ohm resistor for now?
R5 is 10K
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The way you have it in your schematic isn't the same as how you have it wired up!

Florida
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Thanks!!! I will try it out and post the results.
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Florida
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It works perfect! I did not need to use the capacitor.


Thanks for all the help!!!
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The capacitor is used to protect the analog input from transient noisy problems.
This may result from long cables in a electrical noisy environment.
If you are just doing a test you don't need the capacitor.
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The way you have it in your schematic isn't the same as how you have it wired up!

Florida
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Thanks! I will put a capacitor in when I put the probe into my project.



« Last Edit: January 21, 2013, 12:01:39 pm by Drew Davis » Logged

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