Arduino: Blink v1

gistfile1.ino

/*
  Blink
  Turns on an LED on for 1/4 a second, then off for 1/4 second, after the third blink, hold for 1 1/4 seconds and repeat.
 
  This example code is in the public domain.
 */
 
// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;

// the setup routine runs once when you press reset:
void setup() {                
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);     
}

// the loop routine runs over and over again forever:
int i = 0;                   // create a 'crement var
int block = 250;             // create default time unit
void loop() {
  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(block);              // wait for a 1/4 second
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW

  if (i == 2) {
    delay( 5 * block );      // wait for 2 seconds after third blink
    i = 0;                   // set i back to 0
  } else {
    delay(block);            // wait for a 1/4 second
    i++;                     // increment i by 1
  }
}