Arduino and Thermocouple K MAX6675


Introduction: Arduino and Thermocouple K MAX6675

Connecting the thermocouple K MAX6675 to an Arduino Mega.

For this example I used a cheap arduino mega 2560 from SainSmart.

The thermocouple K MAX6675 is a convert that allows temperature reading from 0ºC to 1024ºC. You can learn more about it by read the datasheet here.

Step 1: Material

1 - Arduino

2 - ThermoCouple K MAX6675

3 - USB Cable

Step 2: Wiring the Material

So now we connect the thermocouple to the pin 45 to 53 (in the arduino the pins goes in pairs)

Step 3: Coding Like a Pro...

First of all I need to find a Library who help us to communicate with the sensor. After browsing the web for a couple of hours and testing the libraries, I enjoyed that one, ThermoCoupleK from LadyAda who I believe don't mind if we use it.

After looking at some examples I ended with this code (that is close to the one I found).

Step 4: Conclusion

As you can see it's quite easy to create a K-type temperature reader. Now it's up to you to found an application to this instructable.

That's all folks

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22 Discussions

Hi, I would like to use 7 thermocouples and get a reading from each every 200ms, is that something you can do?

hai, can you explain me this part? why used only pin vcc n gnd?


I am trying to use a switch case function and while function based on the temperature read of the thermocouple. However, when I try to have the arduino read the temp to test the while statement nothing happens. How can I have the arduino read the temp for the while statement?


can I use max 31855k ?

my probe is pt100

I want to use this project for artisan software (coffee roaster)

please help me

1 reply


I never tested that one but you can try it. For that you should change the library for this one ( the one I use is fot the MAX6675.

Good Luck


1 year ago

Hi,dude. Where can I get the coding for 2 points calibration of thermocouple ? Thank you in advance

hi . how can i wire max6675 to ramps ? and what config should i do in repetier firmware ?

1 reply

I'm using Marlin, so can't tell about repetier. But search your sketches for 6675 and you will eventually find the according #defines.

I'm a supreme noob. Should I have another file that the code is looking for?

I'm getting an error :(

Arduino: 1.6.7 (Mac OS X), Board: "Arduino/Genuino Uno"

/xxx/xxx/Downloads/ThermoCoupleK/ThermoCoupleK.ino:1:21: fatal error: max6675.h: No such file or directory

#include <max6675.h>


compilation terminated.

exit status 1

Error compiling.

1 reply

Put the max6675.cpp and .h in the same folder as where your .ino is located. Open the .ino once again. You should now see two more tabs in the Arduino IDE for the both max6676 files.

how if use 5 thermocouple in one arduino it si possible or not ? :)

1 reply

Just use the CS pin to select the individual couple. Only the one that has CS set high will response on the data line.

does the max6675 IC works with any brand of k-type thermocouple? i am using this one

but the measurements on the serial terminal are very wrong. The impedance of my thermocouple is less than 2 ohm. Can you explain me please how to use correctly my thermocouple with the IC ?

1 reply


I'm not really sure how it will work cause the TC-K range is between 0-800ºC and the MAX6675 is between 0-1023.75ºC. You must need to adjust the limits to match the same values.

But as I said, I not sure it will work, if someone can help here it will be great.


2 years ago

fixed problem..

both controllers from ebay are faulty,

made my own and works great, thank you for your splendid tutorial..

1 reply

Happy to ear that.

Thanks for the support and good luck with your development.


2 years ago

the model is MAX6675
pinout is : gnd, vcc, sck, cs, so

hi my pinout is :




I tied :




but no joy, would you know my pinout to yours

1 reply

Hey there,

is your thermocouple a MAX6675? Check the annotation on the thermocouple board and let me know your model to try to help you.


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