//Old code

int notes[] = { 262, 294, 330, 349 };

void setup() {
  Serial.begin(9600);
}

void loop() {
  int keyVal = analogRead(A0);
  Serial.println(keyVal);

  if (keyVal == 1023) {
    tone(8, notes[0]);
  } else if (keyVal >= 990 && keyVal <= 1010) {
    tone(8, notes[1]);
  } else if (keyVal >= 505 && keyVal <= 515) {
    tone(8, notes[2]);
  } else if (keyVal >= 5 && keyVal <= 10) {
    tone(8, notes[3]);
  } else {
    noTone(8);
  }
}

//New code

// create an array of notes
// the numbers below correspond to the frequencies 
int notes[] = { 5000, 400, 1000, 500 }; // note that tones were changed

void setup() {
  Serial.begin(9600);
}

void loop() {
  int keyVal = analogRead(A0);
  Serial.println(keyVal);

  if (keyVal == 1023) {
  
    tone(8, notes[0]);
  } else if (keyVal >= 990 && keyVal <= 1010) {
    tone(8, notes[1]);
  } else if (keyVal >= 505 && keyVal <= 515) {
    tone(8, notes[2]);
  } else if (keyVal >= 5 && keyVal <= 10) {
    tone(8, notes[3]);
  } else {
    noTone(8);
  }
}