ติด error ที่ #define DHTTYPE DHT21 ขอคำแนะนำหน่อยครับ

#include <DHT.h>
#define DHTPIN 2 // what digital pin we’re connected to
#define DHTTYPE DHT21 // DHT 11
DHT dht(DHTPIN, DHTTYPE);

void setup() { Serial.begin(9600);
Serial.println(“DHT21 test!”);
dht.begin();
}

void loop() {
// Wait a few seconds between measurements.

  float h = dht.readHumidity();
  float t = dht.readTemperature();

// Check if any reads failed and exit early (to try again).
if(isnan(h) || isnan(t))
{
Serial.println(“Failed to read from DHT sensor!”);

  }
  else
  {
     Serial.print("Time: ");
     time = millis()/1000;
     Serial.print(time);
      Serial.print(" secs\t");
      Serial.print("Humidity: ");
      Serial.print(h);
      Serial.print(" %\t");
      Serial.print("Temperature : ");
      Serial.print(t);
      Serial.print(" *C ");
  }