int LED = 13; int data; void setup() { Serial.begin(9600); pinMode(LED,OUTPUT); digitalWrite(LED,LOW); } void loop() { while(Serial.available()) { data = Serial.read(); } if(data == '1') { digitalWrite(LED,HIGH); Serial.println("LED turned on"); } else if(data == '0') { digitalWrite(LED,LOW); Serial.println("LED turned off"); } }