We have a Adafruit Thermocouple Sensor w/MAX31855K. There are a couple of posts that mention it but don’t see anything specific in the forums for Xojo code.

Code at

Can anyone help with Xojo conversion on this?

would like to help, as I even have the max31855 in stock and some thermocouples …
but I don’t have a raspberry 2 only have a 1 version so cannot test it further with Xojo .

only a small question: what is it for ?
a Pi to read temperatures is completely overkill … an arduino or an esp8266 is far enough for that
and the esp8266 can be a web server you can read easily from a xojo desktop app.

This will eventually go into an electric kiln controller (my wife creates her own jewelry). Already have an 25A solid state relay to power the coil and I need to measure the temp’s which get hot enough to melt glass.

The goal is to have a PID loop control the temperature, and then have the Pi run temperature programs (set point for x number of minutes), display a graph and other information, and keep a historical record of set point vs actual temps and times. The hardware portion is the big learning curve for me a the rest is pretty easy other than that I have to do all this without a remote debugger.

I would use an esp8266, it is an arduino with wifi inside, costs $3 or so
has lots of rams, can be programmed with the free arduino IDE version >1.64
you can program it as a web server (lots of examples with the arduino ide)
monitor your temperatures, send them to a free service like and see curves in real time

and you already have the device header for the max31855 and arduino !

Look, I appreciate the advice, but I’m doing this on the Pi. I’m a Xojo developer that blogs about Xojo, does Xojo training videos, makes Xojo developer tools, and does Xojo consulting. From that perspective the Arduino makes no sense for me at this point in time.

Looks like the K is a 1Wire device. If it is so, it should be easy to adapt the code from pigpio.OneWireTemperatureSensor. Or do you explicitely need a direct GPIO approach?

An example program for the MAX31855 has been created with Xojo for the Raspberry Pi at:

Glib Error