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Raspithermocouple device

This devices enables the use of MAX31855 to be connected to a K-thermocouple, so you can measure high temperatures. I made this since I would like to measure the exhaust/smoke temperature on my pellet-boiler

Hardware requirements

  • K-Thermocouple
  • A connector between K-thermocouple and MAX31855 breakoutboard
  • Adafruit MAX31855 breakaoutboard
  • Cables from breakoutboard to RPI pin headers


Files are found here: [1]
Copy the raspithermocouple.py script and place it in /op/agocontrol/bin/raspithermocouple.py
Ensure it's owned by root and executable chmod a+x
Copy raspithermocouple.service to here: /lib/systemd/system/raspithermocouple.service


Configuration file is located at /etc/opt/agocontrol/conf.d/raspithermocouple.conf

cs_pin=24    #Chip Select (CS) / Slave Select (SS) pin 
clock_pin=23 #Clock (SCLK / SCK)
data_pin=22  #Data input (SO / MOSI)
units="c"    #(optional) unit of measurement to return, use lowercase. ("c" (default) | "k" | "f")
interval=60 #Secs how often to measure. 600 seconds is default

Enable and start device

 sudo systemctl enable raspithermocouple.service
 sudo systemctl start raspithermocouple.service

Supported sensors

  • K-thermocouple connected to MAX31855KASA

Known problems

  • Get device to report properly in Fahrenheit or Kelvin - I will not focus on this
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