树莓派3b驱动dht11温湿度传感器
1.新建并打开C文件
touch dht11.csudo vim dht11.c
2.编写驱动程序
#include<wiringPi.h>#include<stdio.h>#include<stdlib.h>#include<stdint.h>#define MAX_TIME 85#define DHT11PIN 7#define ATTEMPTS 5 //retry 5 times when no responseint dht11_val[5]={0,0,0,0,0};int dht11_read_val(){uint8_t lststate=HIGH; //last stateuint8_t counter=0;uint8_t j=0,i;for(i=0;i<5;i++)dht11_val[i]=0;//host send start signal pinMode(DHT11PIN,OUTPUT);//set pin to output digitalWrite(DHT11PIN,LOW); //set to low at least 18ms delay(18);digitalWrite(DHT11PIN,HIGH); //set to high 20-40usdelayMicroseconds(40);//start recieve dht responsepinMode(DHT11PIN,INPUT); //set pin to inputfor(i=0;i<MAX_TIME;i++) {counter=0;while(digitalRead(DHT11PIN)==lststate){//read pin state to see if dht responsed. if dht always high for 255 + 1 times, break this while circlecounter++;delayMicroseconds(1);if(counter==255)break;}lststate=digitalRead(DHT11PIN); //read current state and store as last state. if(counter==255) //if dht always high for 255 + 1 times, break this for circlebreak;// top 3 transistions are ignored, maybe aim to wait for dht finish response signalif((i>=4)&&(i%2==0)){dht11_val[j/8]<<=1;//write 1 bit to 0 by moving left (auto add 0)if(counter>16)//long mean 1dht11_val[j/8]|=1;//write 1 bit to 1 j++;}}// verify checksum and print the verified dataif((j>=40)&&(dht11_val[4]==((dht11_val[0]+dht11_val[1]+dht11_val[2]+dht11_val[3])& 0xFF))){printf("RH:%d,TEMP:%d\n",dht11_val[0],dht11_val[2]);return 1;}elsereturn 0;}int main(void){int attempts=ATTEMPTS;if(wiringPiSetup()==-1)exit(1);while(attempts){ //you have 5 times to retryint success = dht11_read_val();//get result including printing outif (success) { //if get result, quit program; if not, retry 5 times then quitbreak;}attempts--;delay(2500); }return 0;}
按esc，然后输入:wq保存退出。
3.编译c文件
需安装wiringPi开发库，安装教程详见本博主博客：树莓派安装wiringPi开发库
输入命令：
gcc -Wall -o dht11 dht11.c -lwiringPi
gcc是编译器，-Wall是在编译时显示警告信息，-o dht11.c是将dht11.c文件编译成文件名为dht11的可执行文件，-lwiringPi是将wiringPi头文件包含在可执行文件中。
4.运行程序
输入命令：
sudo ./dht11
可以看到湿度和温度值都正确的打印在了屏幕上。
