MAX6675-temp.py

#!/usr/bin/python
# coding: utf8

# Copyright (c) 2014 Adafruit Industries
# Author: Tony DiCola
# Modifications by Michael Maier, 2020
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

# Can enable debug output by uncommenting:
#import logging
#logging.basicConfig(level=logging.DEBUG)

import time
import Adafruit_GPIO.SPI as SPI
import MAX6675.MAX6675 as MAX6675

from subprocess import call

SENSOR_FOLDER = '/run/sensors/'
SENSOR_NAME = 'max6675' # lowercase
LOGFILE = SENSOR_FOLDER + SENSOR_NAME + '/last'

call(["mkdir", "-p", SENSOR_FOLDER + SENSOR_NAME])

# Define a function to convert celsius to fahrenheit.
def c_to_f(c):
        return c * 9.0 / 5.0 + 32.0


# Uncomment one of the blocks of code below to configure your Pi or BBB to use
# software or hardware SPI.

#Raspberry Pi software SPI configuration.
CLK = 25
CS  = 24
DO  = 18
#sensor = MAX6675.MAX6675(CLK, CS, DO)

#Raspberry Pi hardware SPI configuration.
SPI_PORT   = 0
SPI_DEVICE = 0
sensor = MAX6675.MAX6675(spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE))

# BeagleBone Black software SPI configuration.
#CLK = 'P9_12'
#CS  = 'P9_15'
#DO  = 'P9_23'
#sensor = MAX6675.MAX6675(CLK, CS, DO)

# BeagleBone Black hardware SPI configuration.
# SPI_PORT   = 1
# SPI_DEVICE = 0
# sensor = MAX6675.MAX6675(spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE))

# Loop printing measurements every second.
print 'Press Ctrl-C to quit.'
while True:
  temp = sensor.readTempC()
  # print 'Thermocouple Temperature: {0:0.3F}°C'.format(temp, c_to_f(temp))
  output_string =  'temperature_degC{sensor="' + SENSOR_NAME.upper() + '"} ' + str(temp) + '\n'
  logfilehandle = open(LOGFILE, "w",1)
  logfilehandle.write(output_string)
  logfilehandle.close()

  time.sleep(1.0)