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树莓派 DHT11 温湿度传感器读取 C 语言版

2020年5月19日 Spoony 未分类 0

我们之前介绍过三种读取 DHT11 温湿度传感器数值的方法：用系统功能直读、用 Adafruit 的库读取、用 Python 编程读取。
尽管方法很多，但是在不同的树莓派上、使用不同的生产商生产的 DHT11 模块时，可能出现读出的数值无效，或者直接读不出的情况。
那么这边再多提供一种亲测可用的 C 语言版本供大家选择尝试。

传感器连接

Vcc 引脚接 5V
DATA 引脚接 WiringPi 编码 7
GND 引脚接树莓派的 GND

安装 WiringPi

这里使用了 WiringPi 库，如果已经安装过可以跳过这一步。

12345678 sudo apt-get update#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#下载 wiringPigit clone https://github.com/WiringPi/WiringPi#编译 wiringPicd WiringPisudo ./build

编程

源代码如下，保存为 dht11.c。

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899 #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 outputdigitalWrite(pinNumber, 0); // output a high level delay(25);digitalWrite(pinNumber, 1); // output a low level pinMode(pinNumber, INPUT); // set mode to inputpullUpDnControl(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 startwhile (!digitalRead(pinNumber)); //data startdelayMicroseconds(HIGH_TIME);databuf *= 2;if (digitalRead(pinNumber) == 1) //1{databuf++;}} for (i = 0; i < 8; i++){while (digitalRead(pinNumber)); //data clock startwhile (!digitalRead(pinNumber)); //data startdelayMicroseconds(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 outputdigitalWrite(pinNumber, 1); // output a high level printf("Starting...\n");while (1) {pinMode(pinNumber, OUTPUT); // set mode to outputdigitalWrite(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;}