#!/usr/bin/python2.7
# -*- coding: utf-8 -*-  
import RPi.GPIO as GPIO
import time

while 1:
    channel = 2         #引脚号2
    data = []           #温湿度值
    j = 0               #计数器
     
    GPIO.setmode(GPIO.BCM)      #设置引脚模式 以BCM编码格式 
    time.sleep(1)           #延时一秒
    GPIO.setup(channel, GPIO.OUT)  #设置引脚为输出
    GPIO.output(channel, GPIO.LOW)  #将引脚的状态设置为底电平

    time.sleep(0.02)        #给信号提示传感器开始工作
    GPIO.output(channel, GPIO.HIGH) #将引脚的状态设置为高电平
    GPIO.setup(channel, GPIO.IN) #设置引脚为输入
     
    while GPIO.input(channel) == GPIO.LOW:
        continue
     
    while GPIO.input(channel) == GPIO.HIGH:
        continue
     
    while j < 40:
        k = 0
        while GPIO.input(channel) == GPIO.LOW:
            continue
        
        while GPIO.input(channel) == GPIO.HIGH:
            k += 1
            if k > 100:
                break
        
        if k < 8:
            data.append(0)
        else:
            data.append(1)
     
        j += 1
     
    print "sensor is working."
    #print data             #输出初始数据高低电平
     
    humidity_bit = data[0:8]        #分组
    humidity_point_bit = data[8:16]
    temperature_bit = data[16:24]
    temperature_point_bit = data[24:32]
    check_bit = data[32:40]
     
    humidity = 0
    humidity_point = 0
    temperature = 0
    temperature_point = 0
    check = 0
     
    for i in range(8):
        humidity += humidity_bit[i] * 2 ** (7 - i)              #转换成十进制数据
        humidity_point += humidity_point_bit[i] * 2 ** (7 - i)
        temperature += temperature_bit[i] * 2 ** (7 - i)
        temperature_point += temperature_point_bit[i] * 2 ** (7 - i)
        check += check_bit[i] * 2 ** (7 - i)
     
    tmp = humidity + humidity_point + temperature + temperature_point       #十进制的数据相加
     
    if check == tmp:    #数据校验，相等则输出
        print "温度 : ", temperature, ", 湿度 : " , humidity
    else:               #错误输出错误信息，和校验数据
        print "wrong"
        print "温度 : ", temperature, ", 湿度 : " , humidity, " 检查 : ", check, " tmp : ", tmp
    time.sleep(1)
    
GPIO.cleanup()