14、新手入手树莓派教程--DHT11传感器的使用

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设备和环境：

1、树莓派3b；

2、ubuntu mate系统 linux内核是4.4.38

3、DHT11传感器。

功能需求：

1、读取DHT11传感器的数据，并将温湿度打印出来。

功能实现：

1、建立dht11.c文件，然后编写代码，具体如下；

//
//
//mydht11.c
//
#include <wiringPi.h>
#include <stdio.h>
#include <stdlib.h>

typedef unsigned char uint8;
typedef unsigned int  uint16;
typedef unsigned long uint32;

#define HIGH_TIME 32

int pinNumber =1;  //use gpio1 to read data
uint32 databuf;
 
 

uint8 readSensorData(void)
{
    uint8 crc; 
    uint8 i;
 
    pinMode(pinNumber,OUTPUT); // set mode to output
    digitalWrite(pinNumber, 0); // output a high level 
    delay(25);
    digitalWrite(pinNumber, 1); // output a low level 
    pinMode(pinNumber, INPUT); // set mode to input
    pullUpDnControl(pinNumber,PUD_UP);

    delayMicroseconds(27);
    if(digitalRead(pinNumber)==0) //SENSOR ANS
       {
         while(!digitalRead(pinNumber)); //wait to high

      for(i=0;i<32;i++)
       {
       while(digitalRead(pinNumber)); //data clock start
       while(!digitalRead(pinNumber)); //data start
          delayMicroseconds(HIGH_TIME);
          databuf*=2;
           if(digitalRead(pinNumber)==1) //1
            {
                databuf++;
            }
        }

      for(i=0;i<8;i++)
       {
       while(digitalRead(pinNumber)); //data clock start
       while(!digitalRead(pinNumber)); //data start
          delayMicroseconds(HIGH_TIME);
          crc*=2;  
          if(digitalRead(pinNumber)==1) //1
           {
                crc++;
           }
        }
    return 1;
       }
   else
        {
        return 0;
         }
}
 
int main (void)
{

  printf("Use GPIO1 to read data!\n");

  if (-1 == wiringPiSetup()) {
    printf("Setup wiringPi failed!");
    return 1;
  }
 
  pinMode(pinNumber, OUTPUT); // set mode to output
  digitalWrite(pinNumber, 1); // output a high level 

  printf("Enter OS-------\n");
  while(1) {
    pinMode(pinNumber,OUTPUT); // set mode to output
    digitalWrite(pinNumber, 1); // output a high level 
    delay(3000);
    if(readSensorData())
    {
       printf("Congratulations ! Sensor data read ok!\n");
       printf("RH:%d.%d\n",(databuf>>24)&0xff,(databuf>>16)&0xff); 
       printf("TMP:%d.%d\n",(databuf>>8)&0xff,databuf&0xff);
       databuf=0;
     }
    else
     {
        printf("Sorry! Sensor dosent ans!\n");
       databuf=0;
      }
  }
  return 0;
}
//

2、编译

//
gcc -Wall -o dht11 dht11.c -lwiringPi
//

3、运行

//
./dht11
//

4、结果

致谢：

1、树莓派读取DHT11数据的实践思考

2、DHT11 HUMIDITY & TEMPERATURE SENSOR MODULE

3、树莓派读取温湿度传感器DHT11

4、树莓派读取温湿度传感器DHT11（好）

5、DHT11数字湿温度传感器的原理和应用范例