# http://www.reuk.co.uk/wordpress/raspberry-pi/ds18b20-temperature-sensor-with-raspberry-pi/
import os
import glob
import time
os.system('modprobe w1-gpio')
os.system('modprobe w1-therm')
base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob(base_dir + '28*')[0]
device_file = device_folder + '/w1_slave'
def read_temp_raw():
  f = open(device_file, 'r')
  lines = f.readlines()
  f.close()
  return lines
def read_temp():
  lines = read_temp_raw()
  while lines[0].strip()[-3:] != 'YES':
    time.sleep(0.2)
    lines = read_temp_raw()
  equals_pos = lines[1].find('t=')
  if equals_pos != -1:
    temp_string = lines[1][equals_pos+2:]
    temp_c = float(temp_string) / 1000.0
    temp_f = temp_c * 9.0 / 5.0 + 32.0
    return temp_c, temp_f

while True:
  print(read_temp())

add code for keyes ds18b20 temperature sensor