#!/usr/bin/env python
import RPi.GPIO as GPIO
import numpy as np
import time
 
DHTPIN = 17         #引脚号17

GPIO.setmode(GPIO.BCM)      #以BCM编码格式

def read_dht11_dat():
    
    GPIO.setup(DHTPIN, GPIO.OUT)
    GPIO.output(DHTPIN, GPIO.LOW)
    #给信号提示传感器开始工作,并保持低电平18ms以上
    time.sleep(0.02)                #这里保持20ms   
    GPIO.output(DHTPIN, GPIO.HIGH)  #然后输出高电平
    
    GPIO.setup(DHTPIN, GPIO.IN)    
    # 发送完开始信号后得把输出模式换成输入模式，不然信号线上电平始终被拉高
 
    while GPIO.input(DHTPIN) == GPIO.LOW:
        continue
    #DHT11发出应答信号，输出 80 微秒的低电平
    
    while GPIO.input(DHTPIN) == GPIO.HIGH:
        continue
    #紧接着输出 80 微秒的高电平通知外设准备接收数据
    
    
    #开始接收数据
    j = 0               #计数器
    data = []           #收到的二进制数据
    kk=[]               #存放每次高电平结束后的k值的列表
    while j < 40:
        k = 0
        while GPIO.input(DHTPIN) == GPIO.LOW:  # 先是 50 微秒的低电平
            continue
        
        while GPIO.input(DHTPIN) == GPIO.HIGH: # 接着是26-28微秒的高电平，或者 70 微秒的高电平
            k += 1
            if k > 100:
                break
        kk.append(k)
        if k < 8:       #26-28 微秒时高电平时通常k等于5或6
            data.append(0)      #在数据列表后面添加一位新的二进制数据“0”
        else:           #70 微秒时高电平时通常k等于17或18
            data.append(1)      #在数据列表后面添加一位新的二进制数据“1”
 
        j += 1
 
    print("sensor is working.")
    print '初始数据高低电平:\n',data    #输出初始数据高低电平
    print '参数k的列表内容：\n',kk      #输出高电平结束后的k值
    
    m = np.logspace(7,0,8,base=2,dtype=int) #logspace()函数用于创建一个于等比数列的数组
    #即[128 64 32 16 8 4 2 1]，8位二进制数各位的权值
    data_array = np.array(data) #将data列表转换为数组

    #dot()函数对于两个一维的数组，计算的是这两个数组对应下标元素的乘积和(数学上称之为内积)
    humidity = m.dot(data_array[0:8])           #用前8位二进制数据计算湿度的十进制值
    humidity_point = m.dot(data_array[8:16])
    temperature = m.dot(data_array[16:24])
    temperature_point = m.dot(data_array[24:32])
    check = m.dot(data_array[32:40])
    
    print humidity,humidity_point,temperature,temperature_point,check
    
    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
        return humidity, temperature
    else:               #错误输出错误信息
        return False
 
def main():
    print "Raspberry Pi DHT11 Temperature test program\n"
    time.sleep(1)           #通电后前一秒状态不稳定，时延一秒
    while True:
        result = read_dht11_dat()
        if result:
            humidity, temperature = result
            print "humidity: %s %%,  Temperature: %s  ℃" % \
                  (humidity, temperature)
            print '\n' 
            time.sleep(1)

        if result == False:
            print "Data are wrong,skip\n"
            time.sleep(1)
            
def destroy():
    GPIO.cleanup()

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        destroy() 

#!/usr/bin/python
import RPi.GPIO as GPIO
import time
 
channel =4
data = []
j = 0
 
GPIO.setmode(GPIO.BCM)
 
time.sleep(1)
 
GPIO.setup(channel, GPIO.OUT)
GPIO.output(channel, GPIO.LOW)
time.sleep(0.02)
GPIO.output(channel, GPIO.HIGH)
GPIO.setup(channel, GPIO.IN)
 
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)
 
humidity_bit = data[0:8]
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)
  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
 
if check == tmp:
  print("temperature :", temperature, "*C, humidity :", humidity, "%")
else:
  print("wrong")
  print("temperature :", temperature, "*C, humidity :", humidity, "% check :", check, ", tmp :", tmp)
 
GPIO.cleanup()

#!/usr/bin/python
import json
import copy
# 接在上面的lookTemp.py后面写

env = []
if humidity_dht11 is not None and temperature_dht11 is not None:
        data = {"metric":"humidity","tag":"module=dht11","value":humidity}
        env.append(copy.copy(data))
        data = {"metric":"temperature","tag":"module=dht11","value":temperature}
        env.append(copy.copy(data))
if len(env) > 0:
        with open("./env.json", 'w') as f:
                f.write(json.dumps(env))