#!/usr/bin/env python3 import globals import sys from time import sleep, time from threading import Thread DEBUG = False ''' This is based on the widely available DS18B20 temperature probe. It is a 1-wire protocol device that returns temperature directly degrees C. The dataline must go on the Pi GPIO 4 (pin 7) which should be pulled up to VCC with a 4.7K resistor. You have to do several thingsto make this work: 1) Enable 1-wire support in the Pi: edit /boot/config.txt set: dtoverlay=w1-gpio reboot 2) Each 1-wire device is connected to the same pin (7) on the Pi. It distinguishes between them by a uniq address. You have to find that address *for your specific device*. You do this by looking at: ls -l /sys/bus/w1/devices You'll see the ID of your device there. That needs to be set in the line below for this code to work with your device. ''' DS18B20_ID = "28-0416840ac6ff" # This function is called on it's own thread by __main__ # so that it runs continuously in background. class read_temp(Thread): def run(self): probe = open("/sys/bus/w1/devices/%s/w1_slave" % DS18B20_ID) temp = float(probe.readlines()[-1].split()[-1].split("=")[-1])/1000 # Parse probe output globals.CURRENT_TEMP = int(round((temp * 9/5) +32)) # Convert C-F and round into an integer probe.close() def read_temp_probe(): while True: read_temp().start() if DEBUG: sys.stdout.write("Temp: %sF\n" % globals.CURRENT_TEMP) sleep(1) # Run this from the command line if __name__ == "__main__": DEBUG = True read_temp_probe()