#include "DHT.h"

...

define DHTPIN 4 // 定義接腳

...

#define DHTTYPE DHT11   // DHT 11

或

#define DHTTYPE DHT22   // DHT 22  (AM2302)

或

#define DHTTYPE DHT21   // DHT 21 (AM2301)

...

DHT dht(DHTPIN, DHTTYPE);

dht.begin();

float h = dht.readHumidity(); // 讀取攝氏溫度

float t = dht.readTemperature();  // 讀取華氏溫度

float f = dht.readTemperature(true); // 讀取濕度

float hic = dht.computeHeatIndex(t, h, false); // 計算 Heat Index (攝氏)

float hif = dht.computeHeatIndex(f, h); // 計算 Heat Index (華氏)

// 讀取感測器資料失敗，輸出訊息

if (isnan(h) || isnan(t) || isnan(f)) {

    Serial.println("Fail to read!!");

    return;

  }

// Example testing sketch for various DHT humidity/temperature sensors

// Written by ladyada, public domain

#include "DHT.h"

#define DHTPIN 2     // what pin we're connected to

// Uncomment whatever type you're using!

#define DHTTYPE DHT11   // DHT 11 

//#define DHTTYPE DHT22   // DHT 22  (AM2302)

//#define DHTTYPE DHT21   // DHT 21 (AM2301)

// Initialize DHT sensor for normal 16mhz Arduino

DHT dht(DHTPIN, DHTTYPE);

void setup() {

  Serial.begin(9600); 

  Serial.println("DHTxx test!");

  dht.begin();

}

void loop() {

  // Wait a few seconds between measurements.

  delay(2000);

  // Reading temperature or humidity takes about 250 milliseconds!

  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)

  float h = dht.readHumidity();

  // Read temperature as Celsius

  float t = dht.readTemperature();

  // Read temperature as Fahrenheit

  float f = dht.readTemperature(true);

  // Check if any reads failed and exit early (to try again).

  if (isnan(h) || isnan(t) || isnan(f)) {

    Serial.println("Failed to read from DHT sensor!");

    return;

  }

  // Compute heat index

  // Must send in temp in Fahrenheit!

  float hi = dht.computeHeatIndex(f, h);

  Serial.print("Humidity: "); 

  Serial.print(h);

  Serial.print(" %\t");

  Serial.print("Temperature: "); 

  Serial.print(t);

  Serial.print(" *C ");

  Serial.print(f);

  Serial.print(" *F\t");

  Serial.print("Heat index: ");

  Serial.print(hi);

  Serial.println(" *F");

}