#!/usr/bin/python
#-*- coding:utf-8 -*-

import glob
import time

base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob(base_dir + '28*')[0]
device_file = device_folder + '/w1_slave'

def read_rom():
    name_file=device_folder+'/name'
    f = open(name_file,'r')
    return f.readline()

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
        return temp_c



print(' DS19B20 get temperature: %3.3f ℃'% read_temp())