Build fun piano with ultrasonic using Maker Nano RP2040

NanoRP2040Theramin.ino

#define echoPin 12
#define trigPin 13
#define led1 14
#define led2 15
#define buzzer 22  // buzzer pin in Maker Nano RP2040 is 22

// defines variables
long duration; // variable for the duration of sound wave travel
int distance; // variable for the distance measurement

void setup()
{
  Serial.begin(9600);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop()
{
  // Ultrasonic Code
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println("cm");
  
  if (distance < 5) {
    tone(buzzer, 523); // Play tone C
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    delay(500);
    noTone(buzzer);
    digitalWrite(14, LOW);
    digitalWrite(15, LOW);
    delay(500);
  }
  else if (distance < 10) {
    tone(buzzer, 587); // Play tone D
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    delay(500);
    noTone(buzzer);
    digitalWrite(14, LOW);
    digitalWrite(15, LOW);
    delay(500);
  }
  else if (distance < 15) {
    tone(buzzer, 659); // Play tone E
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    delay(500);
    noTone(buzzer);
    digitalWrite(14, LOW);
    digitalWrite(15, LOW);
    delay(500);
  }
  else if (distance < 20) {
    tone(buzzer, 698); // Play tone F
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    delay(500);
    noTone(buzzer);
    digitalWrite(14, LOW);
    digitalWrite(15, LOW);
    delay(500);
  }
  else if (distance < 25) {
    tone(buzzer, 783); // Play tone G
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    delay(500);
    noTone(buzzer);
    digitalWrite(14, LOW);
    digitalWrite(15, LOW);
    delay(500);
  }
  else if (distance < 30) {
    tone(buzzer, 880); // Play tone A
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    delay(500);
    noTone(buzzer);
    digitalWrite(14, LOW);
    digitalWrite(15, LOW);
    delay(500);
  }
  else if (distance < 35) {
    tone(buzzer, 987); // Play tone B
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    delay(500);
    noTone(buzzer);
    digitalWrite(14, LOW);
    digitalWrite(15, LOW);
    delay(500);
  }
  else {
    noTone(buzzer);
    digitalWrite(14, LOW);
    digitalWrite(15, LOW);
  }
}