// simple LED blinking circuit

void setup() // the setup routine runs once when you press reset:
 {
  // define the D2 pin as output:
  pinMode (2, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
  digitalWrite(2, HIGH);// D2 pin on
  delay(1000); // wait 1000ms
  digitalWrite(2, LOW);// D2 pin off
    delay(1000);// wait 1000ms
}