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

LiquidCrystal_I2C lcd(0x27, 16, 2);

long duration;
int distance;

const int trigPin = 10;
const int echoPin = 11;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  Serial.begin(9600);

  lcd.init();
  lcd.backlight();

  lcd.setCursor(0, 0);
  lcd.print("Ultrasonic");
  lcd.setCursor(0, 1);
  lcd.print("Starting...");
  delay(2000);

  lcd.clear();
}

void loop() {

  // Clear trigger
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Send pulse
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read echo
  duration = pulseIn(echoPin, HIGH, 30000);

  // Calculate distance
  distance = duration * 0.034 / 2;

  // Serial Monitor output
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // LCD output
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("Distance:");

  lcd.setCursor(0, 1);
  lcd.print(distance);
  lcd.print(" cm");

  delay(200);
}