树莓派练习程序（温度湿度测量）

温度湿度模块DHT11如下图：

树莓派的引脚如下图：

我们将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。

实物连接如下图：

编程使用WiringPi库，使用wpi引脚编码方式控制GPIO。

代码如下：

#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!
");

    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-------
");
    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!
");
            printf("RH:%d.%d
", (databuf >> 24) & 0xff, (databuf >> 16) & 0xff); 
            printf("TMP:%d.%d
", (databuf >> 8) & 0xff, databuf & 0xff);
            databuf = 0;
        }
        else
        {
            printf("Sorry! Sensor dosent ans!
");
            databuf = 0;
        }
    }
    return 0;
}

输出结果：

参考：

http://blog.csdn.net/liang890319/article/details/8739683