Arduino下读取DHT22温湿度（不使用第三方库）

代码如下：

#include <inttypes.h>

/*

 * LED

 */

 unsigned int LED = ;

/*

 * DHT22配置程序

 */

unsigned int DHT_PIN = ;

#define DHT_OK      1

#define DHT_ERR_CHECK 0

#define DHT_ERR_TIMEOUT -1

float humidity;

float temperature;

unsigned char DHT_read()

{

  // BUFFER TO RECEIVE

  unsigned char bits[] = {,,,,};

  unsigned char cnt = ;

  unsigned char idx = ;

  unsigned char sum;

  // REQUEST SAMPLE

  pinMode(DHT_PIN, OUTPUT);

  digitalWrite(DHT_PIN, LOW);

  delay();

  digitalWrite(DHT_PIN, HIGH);

  delayMicroseconds();

  pinMode(DHT_PIN, INPUT);

  // ACKNOWLEDGE or TIMEOUT

  unsigned int count = ;

  while(digitalRead(DHT_PIN) == LOW)

    if (count-- == ) return DHT_ERR_TIMEOUT;

  count = ;

  while(digitalRead(DHT_PIN) == HIGH)

    if (count-- == ) return DHT_ERR_TIMEOUT;

  // READ OUTPUT - 40 BITS => 5 BYTES or TIMEOUT

  for (int i=; i<; i++)

  {

    count = ;

    while(digitalRead(DHT_PIN) == LOW)

      if (count-- == ) return DHT_ERR_TIMEOUT;

    unsigned long t = micros();

    count = ;

    while(digitalRead(DHT_PIN) == HIGH)

      if (count-- == ) return DHT_ERR_TIMEOUT;

    if ((micros() - t) > ) bits[idx] |= ( << cnt);

    if (cnt == )   // next byte?

    {

      cnt = ;    // restart at MSB

      idx++;      // next byte!

    }

    else cnt--;

  }

  sum = bits[]+bits[]+bits[]+bits[];

  if(bits[] != sum) return DHT_ERR_CHECK;

  humidity = (float)((bits[] << )+bits[])/;

  temperature = (float)((bits[] << )+bits[])/;

  return DHT_OK;

}

void setup() {

   pinMode(,OUTPUT);//指示灯

   pinMode(DHT_PIN,INPUT);

   digitalWrite(DHT_PIN, HIGH);

}

void loop() {

   DHT_read();

   Serial.print("temperature:");

   Serial.println(temperature);

   Serial.println("============end===============");

   delay();

   digitalWrite(LED,HIGH);

   delay(); //Delay

   digitalWrite(LED,LOW);

   delay(); //Delay

}

DHT22数据手册：http://www.waveshare.net/w/upload/b/be/AM2302_V1.1.pdf