Blink Example

/*  Blink - This example code is in the public domain. */

void setup() {
  // initialize the digital pin as an output.
  // Pin 13: Arduino has an LED connected on pin 13
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);   // set the LED on
  delay(1000);              // wait for a second
  digitalWrite(13, LOW);    // set the LED off
  delay(1000);              // wait for a second
}