// Define the pin where the bulb is connected
int bulbPin = 13;

void setup() {
  // Set the pinMode of pin 13 as OUTPUT
  pinMode(bulbPin, OUTPUT);
}

void loop() {
  // Turn the bulb on
  digitalWrite(bulbPin, HIGH);
  
  // Wait for 1 second
  delay(1000);
  
  // Turn the bulb off
  digitalWrite(bulbPin, LOW);
  
  // Wait for 1 second
  delay(1000);
}