Introduction

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CircuitPython driver for the MAX31855 Thermocouple Amplifier Breakout

Dependencies

This driver depends on:

Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle.

Installing from PyPI

On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally from PyPI. To install for current user:

pip3 install adafruit-circuitpython-max31855

To install system-wide (this may be required in some cases):

sudo pip3 install adafruit-circuitpython-max31855

To install in a virtual environment in your current project:

mkdir project-name && cd project-name
python3 -m venv .env
source .env/bin/activate
pip3 install adafruit-circuitpython-max31855

Usage Example

Of course, you must import the library to use it:

import adafruit_max31855

You also need to create an SPI interface object, and a pin object for the chip select pin. You can use any pin for the CS, but we use D5 here:

from busio import SPI
from digitalio import DigitalInOut
import board

spi = SPI(clock=board.SCK, MISO=board.MISO, MOSI=board.MOSI)
cs = DigitalInOut(board.D5)

Next, just create the sensor object:

sensor = adafruit_max31855.MAX31855(spi, cs)

And you can start making measurements:

print(sensor.temperature)

The temperature is read in degrees Celsius (°C). You have to convert it to other units yourself, if you need it.

Contributing

Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.

Documentation

For information on building library documentation, please check out this guide.

Table of Contents

Simple test

Ensure your device works with this simple test.

examples/max31855_simpletest.py
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# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
import board
import busio
import digitalio
import adafruit_max31855

spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
cs = digitalio.DigitalInOut(board.D5)

max31855 = adafruit_max31855.MAX31855(spi, cs)
while True:
    tempC = max31855.temperature
    tempF = tempC * 9 / 5 + 32
    print("Temperature: {} C {} F ".format(tempC, tempF))
    time.sleep(2.0)

adafruit_max31855

This is a CircuitPython driver for the Maxim Integrated MAX31855 thermocouple amplifier module.

  • Author(s): Radomir Dopieralski

Implementation Notes

Hardware:

Software and Dependencies:

class adafruit_max31855.MAX31855(spi, cs)[source]

Driver for the MAX31855 thermocouple amplifier.

reference_temperature

Internal reference temperature in degrees Celsius.

temperature

Thermocouple temperature in degrees Celsius.

temperature_NIST

Thermocouple temperature in degrees Celsius, computed using raw voltages and NIST approximation for Type K, see: https://srdata.nist.gov/its90/download/type_k.tab

Indices and tables