---

#define BUZZER 8
#define LED 9
#define POT A0

int melody[] = {
  262, 294, 330, 349,
  392, 440, 494, 523,
  494, 440, 392, 349,
  330, 294, 262
};

int duration[] = {
  250, 250, 250, 250,
  250, 250, 250, 400,
  250, 250, 250, 250,
  250, 250, 500
};

void setup() {
  pinMode(BUZZER, OUTPUT);
  pinMode(LED, OUTPUT);
}

void loop() {
  int potValue = analogRead(POT);
  int shift = map(potValue, 0, 1023, -100, 100);

  for (int i = 0; i < 15; i++) {
    int frequency = melody[i] + shift;

    if (frequency < 50) {
      frequency = 50;
    }

    tone(BUZZER, frequency);
    digitalWrite(LED, HIGH);

    delay(duration[i]);

    noTone(BUZZER);
    digitalWrite(LED, LOW);

    delay(50);
  }

  delay(500);
}