#define trigPin 5
#define echoPin 18
long duration;
int distance;

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

void loop() {
  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.println(distance);
  delay(100);
}

#include "pitches.h"  // Include pitches.h for defining notes

int distance;
int tonePin = 27;  // Connect to speaker

void setup() {
  Serial.begin(9600);
  pinMode(tonePin, OUTPUT);
}

void loop() {
  distance = measureDistance();
  
  // Mapping distance to frequency (for example, between 100Hz and 2000Hz)
  int frequency = map(distance, 0, 100, 100, 2000);
  tone(tonePin, frequency);
  
  delay(100);
}

int measureDistance() {
  // Function to measure distance using HC-SR04
  // (Code from the previous example)
}