int led = D2;

void setup() {
    
    pinMode( led, OUTPUT );
// D2 is the out put pin

}

void loop() {
    
    for( int i = 0; i < 5; i++ ) {
    //loop for 5 times 
    
        digitalWrite( led, HIGH );
        delay( 500 );

        digitalWrite( led, LOW );
        delay( 500 );
        //each blink is 1/2 second
    
    }
    
    digitalWrite( led, LOW );
    delay( 3000 );
    //stop for 3 seconds after 5 blinks
    
}