首先在該地址下載庫：https://codeload.github.com/nethoncho/Arduino-DHT22/zip/master

使用以下代碼測試：

/*******************************************************

這個程序用來測試DHT22的溫濕度。

********************************************************/
#include <dht.h>

dht DHT;
#define DHT22_PIN 7

void setup()
{
  Serial.begin(
 
115200);
  Serial.println("DHT TEST PROGRAM ");
  Serial.print("LIBRARY VERSION: ");
  Serial.println(DHT_LIB_VERSION);
  Serial.println();
  Serial.println("Type,\tstatus,\tHumidity (%),\tTemperature (C)");
}

void loop()
{
  Serial.print("DHT22, \t");
  int chk = DHT.read22(DHT22_PIN);  //讀取數據
 

  switch (chk)
  {
    case DHTLIB_OK:  
                Serial.print("OK,\t"); 
                break;
    case DHTLIB_ERROR_CHECKSUM: 
                Serial.print("Checksum error,\t"); 
                break;
    case DHTLIB_ERROR_TIMEOUT: 
                Serial.print("Time out error,\t
 
"); 
                break;
    default: 
                Serial.print("Unknown error,\t"); 
                break;
  }
  // 顯示數據
  Serial.print(DHT.humidity, 1);
  Serial.print(",\t");
  Serial.println(DHT.temperature, 1);

  delay(1000);
}

Arduino Leonardo讀取DHT22溫濕度傳感器