树莓派驱动DHT温湿度传感器的3种方法

一、使用Adafruit_Python_DHT

使用 Adafruit 读取 DHT11 温湿度传感器 | 树莓派实验室树莓派（Raspberry Pi）中文资讯站，提供丰富的树莓派教程和DIY资讯。https://shumeipai.nxez.com/2018/05/16/dht11-temperature-and-humidity-sensor-raspberry-pi.html

二、使用升级版CircuitPython-DHT

Python Setup | DHT Humidity Sensing on Raspberry Pi or Beaglebone Black with GDocs Logging | Adafruit Learning Systemhttps://learn.adafruit.com/dht-humidity-sensing-on-raspberry-pi-with-gdocs-logging/python-setup

三、经过C语言编译

        上面两种方法都有bug，在获取一次温湿度后，GPIO一直处于高电平，导致下一次读取一直读不到。

        因此可使用直接读取信号线的方式。

        这里用C来编译，也可以python中直接写。

//
//mydht11.c
//
#include 
#include 
#include typedef unsigned char uint8;
typedef unsigned int  uint16;
typedef unsigned long uint32;#define HIGH_TIME 32int pinNumber = 7;  //use gpio1 to read data
uint32 databuf;uint8 readSensorData(void)
{uint8 crc; uint8 i;pinMode(pinNumber,OUTPUT); // set mode to outputdigitalWrite(pinNumber, 1); // output a low leveldelayMicroseconds(4);digitalWrite(pinNumber, 0); // output a high level delay(25);digitalWrite(pinNumber, 1); // output a low leveldelayMicroseconds(60); pinMode(pinNumber, INPUT); // set mode to inputpullUpDnControl(pinNumber,PUD_UP);if(digitalRead(pinNumber)==0) //SENSOR ANS{while(!digitalRead(pinNumber)); //wait to highdelayMicroseconds(80);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)
{if (-1 == wiringPiSetup()) {//printf("Setup wiringPi failed!");return 1;}pinMode(pinNumber, OUTPUT); // set mode to outputdigitalWrite(pinNumber, 1); // output a high level //while(1) //{pinMode(pinNumber,OUTPUT); // set mode to outputdigitalWrite(pinNumber, 1); // output a high level //delay(3000);if(readSensorData()){//printf("OK!\n");//printf("RH:%d.%d\n",(databuf>>24)&0xff,(databuf>>16)&0xff); //printf("TMP:%d.%d\n",(databuf>>8)&0xff,databuf&0xff);printf("{\"RH\":\"%d.%d\", \"TMP\":\"%d.%d\"}",(databuf>>24)&0xff,(databuf>>16)&0xff,(databuf>>8)&0xff,databuf&0xff);databuf=0;}else{printf("");databuf=0;}//}return 0;
}

然后编译（注意这里-I使用了wiringPi）：

gcc a.c -o dht11 -lwiringPi

然后就可以调用了：

./dht11 

之后再Python中调用：

import json
import subprocessdef updateTempHum():res = json.loads(subprocess.check_output('./dht11', timeout=5).decode('utf-8'))print(res)print(res['RH'])print(res['TMP'])

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