// ESP32 Sequential LED ON Program
// LED1 -> LED21 one by one

const int leds[] = {
  2, 4, 5, 12, 13, 14, 15,
  16, 17, 18, 19,
  21, 22, 23,
  25, 26, 27,
  32, 33,
  2, 4
};

const int totalLEDs = 21;

void setup() {

  for (int i = 0; i < totalLEDs; i++) {
    pinMode(leds[i], OUTPUT);
    digitalWrite(leds[i], LOW);
  }
}

void loop() {

  // Turn ON LEDs sequentially
  for (int i = 0; i < totalLEDs; i++) {

    digitalWrite(leds[i], HIGH);

    delay(200);
  }

  delay(1000);

  // Turn OFF LEDs sequentially
  for (int i = 0; i < totalLEDs; i++) {

    digitalWrite(leds[i], LOW);

    delay(100);
  }

  delay(500);
}