void setup() {
  //intialize digital pin 9 as an output.
  pinMode(9, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
  digitalWrite(9,  HIGH ); //turn the LED on (HIGH is the voltage level)
  delay (1000); // wait for a second 
  digitalWrite(9,  LOW ); // turn the LED off by making the
delay(1000); // wait for a second 
}