Arduino Play (micro)music Without Shield

For a project of an art collective, I made a music-playing with Arduino. Music begins with ultrasonic sensor.

The code for the music you write by hand, play by ear!

My code is a little part from the Carmen of Bizet

//Antonio Mainenti  http://soundobject.eu/   Credit: Melo

#define trigPin 7 // pin trig
#define echoPin 6 //pin echo
#define buzzer 9 // buzzer or output

int variabile; //repeats 4 times the first part
int freq = 294; //D
int freq2 = 440; //A
int freq3 = 698; //F
int freq4 = 440; //A
int freq5 = 294; //D
int freq6 = 587; //D
int freq7 = 554; //C#
int freq8= 523; //C
int freq9= 494; //B
int freq10= 466; //A#

int durata = 7000; //duration of notes

int durata2 = 500;

int durata3 = 70;
int durata4 = 3000;
int durata5 = 1000;
int durata6 = 100;

void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzer, OUTPUT);
 
}
void loop() {
  long duration, distance;
  digitalWrite(trigPin, LOW); 
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;
  
   for(variabile=0; variabile<4; variabile++) 
   // repetition
   {
  
 if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq, durata);
    //tone(pin, frequency, duration) 
   
  }
  delay(500);
  
    if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq2, durata2);
    //tone(pin, frequency, duration)
   
  }
  delay(200);
  
   if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq3, durata3);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
  
   if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq4, durata4);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
  
   if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq5, durata5);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
   }
  
  
  //second part
  
  
    if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq6, durata5);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
    if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq7, durata5);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
  
    if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq8, durata6);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
    if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq8, durata6);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
    if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq8, durata2);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
   if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq9, durata5);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
   if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq10, durata);
    //tone(pin, frequency, duration)
   
  }
  delay(500);
  if (distance > 100 || distance <= 0){
    Serial.println("Out of range");
    noTone(buzzer);
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
    tone (buzzer, freq2, durata);
    //tone(pin, frequency, duration)
   
  }
  delay(1000);
  
  
}

ultrasonic sensor:

VCC----- 5V

TRIG-----pin7

ECHO-----pin6

OUT

GND----gnd

audio out:

arduino pin9----10k resistor-----out

gnd----4,7k resistor----out

one note, one frequency.

for example:

A4= 440

one note, one duration