The MAX6675 is a cold-junction-compensated K-type thermocouple-to-digital converter from Maxim, commonly found on cheap thermocouple interfaces sold for the Arduino (such as the "HW-550" board). The datasheet for the MAX6675 is available from Maxim's website.

With the included library (which depends on Python spidev) you can read a thermocouple temperature from one of these chips using Python 3 on Linux through Linux's kernel spidev driver.

This code was tested with a CH341A based USB SPI interface, though it should work with other interfaces so long as they're supported by spidev.

Create a Max6675 object, optionally passing it a bus and device number (otherwise these both default to 0).

>>> from max6675 import Max6675
>>> sensor = Max6675()

Then read the temperature from the converter by calling the read method. Note that other drivers for this converter enforce a minimum interval between reads of 250 milliseconds, which I have also implemented. You may be able to reduce this period at the cost of accuracy. Polling more often than the minimum interval will otherwise return a locally cached value.

>>> while True:
...     print(sensor.read())
...     time.sleep(sensor.read_period)
... 
22.75
23.5
22.75
23.5
23.25
23.25
23.25
23.5

If the MAX6675 chip can't detect a thermocouple connected then calling read will raise a max6675.ThermocoupleError exception.

Optionally when finished with the converter call the object's close method to release the SPI bus.

>>> sensor.close()