// the setup function runs once when you press reset or power the board void setup() { // initialize digital pin LED_BUILTIN as an output. pinMode(2, OUTPUT); } // the loop function runs over and over again forever void loop() { digitalWrite(2, HIGH); // turn the LED on (HIGH is the voltage level) delay(1000); // wait for a second digitalWrite(2, LOW); // turn the LED off by making the voltage LOW delay(1000); // wait for a second }