【树莓派5 测评】--4.DHT11温湿度读取
本帖最后由 dirty123 于 2024-4-14 09:55 编辑树莓派5有多种方式读取使用传感器，本篇讲述使用WiringPi 库，编写C语言代码，驱动实现对DHT11传感器温湿度的读取。
一.环境、硬件准备
1.安装 WiringPi：
①系统更新sudo apt-get update②这里需要使用到WiringPi库，通过git克隆.通过git --version查询安装及版本，若没安装如下安装git
sudo apt-get install git-core
③接着下载 wiringPi库，如下
git clone https://github.com/WiringPi/WiringPi
④编译安装 wiringPi
cd WiringPi
sudo ./build
图1:WiringPi安装
2.安装好WiringPi后，命令gpio readall查询开发板WiringPi引脚编号对应情况,这里选择7脚作为与DHT11的数据通讯引脚
图2:引脚编号
3.开发板接好DHT11传感器
图3:开发板接好DHT11传感器
二.代码编写编译运行
1.编写dht11.c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 = 7;
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("PIN:%d\n", pinNumber);
if (-1 == wiringPiSetup()) {
printf("Setup wiringPi failed!");
return 1;
}
pinMode(pinNumber, OUTPUT); // set mode to output
digitalWrite(pinNumber, 1); // output a high level
printf("Starting...\n");
while (1)
{
pinMode(pinNumber, OUTPUT); // set mode to output
digitalWrite(pinNumber, 1); // output a high level
delay(3000);
if (readSensorData())
{
printf("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("Sensor dosent ans!\n");
databuf = 0;
}
}
return 0;
}
2.编译
gcc -Wall -o dht11 dht11.c -lwiringPi
编译完出现可执行文件如下
图4:编译
3.运行
sudo ./dht11
这时可以看到读出的传感器DHT11的湿度与温度，如下
图5:传感器DHT11的湿度与温度
至此实现对DHT11传感器温湿度的读取。
页:
[1]