int speakerPin = 10, length = 26, tempo = 300, duration, distance;
int beats[] = { 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2};
char notes[] = "eeeeeeegcde";
const int trigPin = 5;
const int echoPin = 4;
const int trigDistance = 100;

void playTone(int tone, int duration);
void playNote(char note, int duration);

void setup() {
  pinMode(speakerPin, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}
void loop() {
  digitalWrite(trigPin, LOW);
  digitalWrite(trigPin, HIGH);
  delay(1);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  if (distance <= trigDistance) {

    for (int i = 0; i < length; i++) {
      if (notes[i] == ' ') {
        delay(beats[i] * tempo);
      } else {
        playNote(notes[i], beats[i] * tempo);
      }
      delay(tempo / 2);
    }
  }
  delay(10000);
}

void playTone(int tone, int duration) {
  for (long i = 0; i < duration * 1000L; i += tone * 2) {
    digitalWrite(speakerPin, HIGH);
    delayMicroseconds(tone);
    digitalWrite(speakerPin, LOW);
    delayMicroseconds(tone);
  }
}
void playNote(char note, int duration) {
  char names[] = { 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'C' };
  int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014, 956 };
  for (int i = 0; i < 8; i++) {
    if (names[i] == note) {
      playTone(tones[i], duration);
    }
  }
}