// Define LED pin
#define LED_PIN 2

// Setup function
void setup() {
  // Set LED pin as output
  pinMode(LED_PIN, OUTPUT);
}

// Loop function
void loop() {
  // Turn on LED
  digitalWrite(LED_PIN, HIGH);
  // Delay for 1 second
  delay(1000);
  
  // Turn off LED
  digitalWrite(LED_PIN, LOW);
  // Delay for 1 second
  delay(1000);
}