Arduino Uno Blink LED

void setup() {

// initialize digital pin LED_BUILTIN as an output.

pinMode(13, OUTPUT);

}

// the loop function runs over and over again forever

void loop() {

digitalWrite(13, HIGH); // turn the LED on (HIGH is the voltage level)

delay(5000); // wait for a second

digitalWrite(13, LOW); // turn the LED off by making the voltage LOW

delay(5000); // wait for a second

}