Converting Thermistor reading to C

Hi I have a central heating stove with couple of thermistors provided. It displays the temps on LCD but I wanted to hookup Arduino to have some historical data.

After plugging sensors into analog input, I have those RAW readings: Temp 1 reading: 270 [26 C on LCD display] Temp2 reading: 454 [54 C on LCD display]

I've tried couple of formulas for converting those reading to C but I can't find the right one.

I would appreciate any help solving this ;)

Regards, Marcin

Assuming relationship is linear:

Actual T. = arduino reading * 0.152 - 15.08


If the sensors are simple thermistors, then their resistance is not a linear function of temperature and that has to be corrected by software. You need to know the curve of resistance versus temperature in order to choose the correction curve.

Also, the "raw" reading that you get depends on how you connected the thermistor to the Arduino, which you did not describe.

You can have a look on this tutorial. Recently I did the same. This tutorial is very helpful.