void setup() { 
  Serial.begin(9600); 
  pinMode(2, OUTPUT); 
  Serial.println("Masukan teks 'ON/OFF' :"); 

   } 
  void loop() { 
     if (Serial.available()) 
 { String perintah = 
  Serial.readStringUntil('\n');
   if (perintah == "1" )
     { digitalWrite(2, HIGH); 
   Serial.println("Led Menyala"); 
    } 
    else if (perintah == "0") 
    { digitalWrite(2, LOW); 
    Serial.println("Led Mati"); 
     } 
     } 
  }