int ledPin = D2;
void setup() {
  // We want to tell the Argon that we'll use
  // D2 as an output pin.
  pinMode(ledPin, OUTPUT);
}

void loop() {
    // blink 5 times for 0.5 sec
    int i = 0;
    while (i < 5) {
        digitalWrite(ledPin, HIGH);
        delay(500);
        
        digitalWrite(ledPin, LOW);
        delay(500);
        i ++;
    }
    // sleep for 3 sec
    digitalWrite(ledPin, LOW);
    delay(3000);
}