Driver library for the MAX31865 RTD chip
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MAX31865 Arduino Library

The files in this folder provide an Arduino driver for the MAX31865 RTD chip and example code that illustrates how to use it.

Original code was written by olewolf, modified by Charles-Henri Hallard

Code based on following datasheet

##Features List of features I added from the original library:

  • Added option to set Reference resistor at object instantiation
  • Corrected threshold (set/get) not consistent problem
  • added soft reconfiguration register with less option (to avoid SPI communication) and not setting again threshold
  • added method to get reference resistor value cfg_ref()
  • added method to get only fault status register fault_status()
  • added method to get only configuration register config_register()

###Installation Copy the content of this folder (zip file) library in your Arduino libraries folder in your sketchbook location, you should have now "your_sketchbook_folder/libraries/max31865" and this folder should contains the .cpp and .h files.
To find your Arduino sketchbook location folder, in Arduino IDE, go to File>Preferences in the Arduino IDE.
See this tutorial on Arduino libraries.

###Sample usage

  • Read_Temperature Basic reading temperature and serial display (original code author)
  • Full_Test_Oled A powerfull testing sketch, the one I use to test my boards, It has full display on I2C OLED 128x64 and on Serial. Each step is detailled, it can see if breakout is connected, communication are good, and MAX31865 breakout board is well configured and see PT100/PT1000. It mainly use all library feature and use MAX31865 in 1-Shot mode.
  • Full_Test_Serial same as above but without OLED display, serial only.

##Blog dedicated post you can find it on my blog here


  • When I created the MAX31865 breakout board, I needed a library to be able to read results. I then found this one which was working file. I just added on it the features I needed, thank to Original library author olewolf.

##License Same as original,

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see

##Misc See news and other projects on my blog