#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);  // Set the LCD address to 0x27 for a 16 chars and 2 line display

const int trigPin = 9;  // Trigger pin of the ultrasonic sensor
const int echoPin = 10; // Echo pin of the ultrasonic sensor
long duration;
int distance;

void setup() {
  lcd.init();                      // Initialize the LCD
  lcd.backlight();                 // Turn on backlight
  pinMode(trigPin, OUTPUT);       // Set trigger pin as OUTPUT
  pinMode(echoPin, INPUT);        // Set echo pin as INPUT
  lcd.print("Distance:");         // Print "Distance:" on LCD
}

void loop() {
  // Clear the display
  lcd.setCursor(0, 1);
  lcd.print("              ");
  
  // Trigger the ultrasonic sensor by sending a 10 microsecond HIGH pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Measure the duration of the echo pulse
  duration = pulseIn(echoPin, HIGH);
  
  // Calculate the distance in centimeters
  distance= duration*0.034/2;
  
  // Print the distance on LCD
  lcd.setCursor(0, 1);
  lcd.print(distance);
  lcd.print(" cm");
  
  // Delay before next measurement
  delay(500);
}