Ultrasonic sensor interfacing with Arduino

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20, 4); // I2C address 0x27, 20 column and 4 rows

int trigPin = 9;    // TRIG pin
int echoPin = 8;    // ECHO pin

float duration_us, distance_cm;

void setup() {
  lcd.init();               // initialize the lcd
  lcd.backlight();
  pinMode(trigPin, OUTPUT); // config trigger pin to output mode
  pinMode(echoPin, INPUT); 
  lcd.clear();              // config echo pin to input mode
}

void loop() {
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // measure duration of pulse from ECHO pin
  duration_us = pulseIn(echoPin, HIGH);

  // calculate the distance
  distance_cm = 0.017 * duration_us;
  

  lcd.setCursor(0, 0);
  lcd.print("DISTANCE IN CM-");
  lcd.setCursor(0, 1);
  lcd.print(distance_cm);

  delay(10);

}