因为试过一些方法，不同的树莓派上、不同的传感器可能出现读出的数值有偏差。
只好多提供几种方案给大家选择。

编程使用WiringPi库，Vcc引脚连接物理接口2，DATA引脚连接物理接口40，GND引脚连接物理接口6。

```
#如果之前没有安装过 git，执行下面的命令安装一下
sudo apt-get install git-core
sudo apt-get update
#下载 wiringPi
#git clone git://git.drogon.net/wiringPi
git clone https://github.com/WiringPi/WiringPi
#编译 wiringPi
cd WiringPi
./build
```
源代码如下，保存为 dht11.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 = 29;
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;
}
```
```
gcc -Wall -o dht11 dht11.c -lwiringPi
sudo ./dht11
```