void setup() {
  // put your setup code here, to run once:
    pinMode(8, OUTPUT);
    digitalWrite(8, 0);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(8, 0);   
  delay(500);                       
  digitalWrite(8, 1);    
  delay(500);
  digitalWrite(8, 1);    
  delay(500);  
}