#define TRIG_PIN 23 // ESP32 pin GPIO23 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN 22 // ESP32 pin GPIO22 connected to Ultrasonic Sensor's ECHO pin
#define MAX_DISTANCE_CM 400 // Maximum distance supported by the sensor (adjust based on sensor specifications)

float duration_us, distance_cm;

void setup() {
  // begin serial port
  Serial.begin(9600);

  // configure the trigger pin to output mode
  pinMode(TRIG_PIN, OUTPUT);
  // configure the echo pin to input mode
  pinMode(ECHO_PIN, INPUT);
}

void loop() {
  // generate a 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(5);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // measure the duration of pulse from ECHO pin
  duration_us = pulseIn(ECHO_PIN, HIGH);

  // calculate the distance
  distance_cm = duration_us * 0.034 / 2;

  // check for out-of-range measurements
  if (distance_cm >= 2 && distance_cm <= MAX_DISTANCE_CM) {
    // print the value to Serial Monitor
    Serial.print("Distance: ");
    Serial.print(distance_cm);
    Serial.println(" cm");
  } else {
    // print out-of-range message
    Serial.println("Out of range");
  }

  delay(500);
}