how i can reproduce a frequency related with distance (HSC3 ultrasonic sensors)

Projects Programming
1

I have this frequencys (NOTE) AND i would like to relate with the distance if my ultrasonic sensor

Thanks in advance

#include <NewPing.h> // https://bitbucket.org/teckel12/arduino-new-ping/downloads/
const byte UltrasonicPin = 5;
const unsigned int MaxDistance = 200;


NewPing sonar(UltrasonicPin, UltrasonicPin, MaxDistance);

#include <SoftwareSerial.h>
SoftwareSerial DFPlayerSerial(10, 11); // RX, TX


#include <NewPing.h>

float distance() //distance-reprdouce one frequency


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

void loop()
{
 Serial.begin(9600);

//delay(noteDuration);
delay (0);


  if (distance < 10) {
    // distance less than 10cm
tone(4, melody[thisNote],noteDuration*1);
    REPRODUCE NOTE1
  
    
  } else if (distance < 20) {
    // distance between 10cm and 20cm
    reproduce NOTE2
    
    
  } else if (distance < 50) {
    // distance between 20cm and 50cm
    reproduce NOTE3
  } else {
    // distance more than 50cm
    reproduce NOTE4
  }
}

#define NOTE_1 300
#define NOTE_2 280
#define NOTE_3 260
//#define NOTE_4 240
//#define NOTE_5 220
//#define NOTE_6 200
//#define NOTE_7 180
//#define NOTE_8 160
//#define NOTE_9 140
//#define NOTE_10 120
2

Look at the examples that come with the NewPing library. They will show you how to measure the distance.