int Led=13;//define LED port int buttonpin=2; //define switch port int val;//define digital variable val void setup() { pinMode(Led,OUTPUT);//define LED as a output port pinMode(buttonpin,INPUT);//define switch as a output port } void loop() { val=digitalRead(buttonpin);//read the value of the digital interface 3 assigned to val if(val==HIGH)//when the switch sensor have signal, LED blink { digitalWrite(Led,HIGH); } else { digitalWrite(Led,LOW); } }