How to make talking Voltmeter at home

Arduino music jan gan man adhi 

Arduino code

int speakerPin = 9; //buzzer is connected to Pin 9 of the Board.
int LEDPin = 10;
int length = 155; // the number of notes
char notes[] = "cdeeeeeeeeeeedef eeedddbdc cgggggfgggfag fffeefdfe eeeeedgggff eeeddddbdc cdeeeedef efgggfedfe eeddddbdc cgggggfgggfag fffeefdfe cbc bab aga cc dd ee de f _________ "; // a space represents a rest
int beats[] = { 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1  };//Duration of each note
int tempo = 300; //Change song speed here

void playTone(int tone, int duration) {  //creating a square wave for the given duration
  for (long i = 0; i < duration * 1000L; i += tone * 2) {
    digitalWrite(speakerPin, HIGH);
    digitalWrite(LEDPin, HIGH);
    delayMicroseconds(tone);
    digitalWrite(speakerPin, LOW);
    digitalWrite(LEDPin, LOW);
    delayMicroseconds(tone);
  }
}

void playNote(char note, int duration) { //Assigning high time for the notes
  char names[] = { 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'C' };
  int tones[] = { 956, 851, 758, 716, 638, 568, 1014, 478 };

  // play the tone corresponding to the note name
  for (int i = 0; i < 8; i++) {
    if (names[i] == note) {
      playTone(tones[i], duration);
    }
  }
}

void setup() {
  pinMode(speakerPin, OUTPUT); // Setting pin 9 as an OutPut Pin
   pinMode(LEDPin, OUTPUT);
}

void loop() {  //Main function
  for (int i = 0; i < length; i++) {  //For the length of the tune array
    if (notes[i] == ' ') {  //take space as rest
      delay(beats[i] * tempo); // rest
    } else {
      playNote(notes[i], beats[i] * tempo); //play the corresponding note for the corresponding beat
    }

    // pause between notes
    delay(tempo / 2);
  }
}