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

#define TRIG_PIN 6
#define ECHO_PIN 18

LiquidCrystal_I2C lcd(0x27, 16, 2);  // I2C address 0x27, 16 column and 2 rows

void setup() {
  Serial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Distance:");
}

void loop() {
  // Send ultrasonic pulse
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Read echo time
  long duration = pulseIn(ECHO_PIN, HIGH);
  long distance = duration * 0.034 / 2;

  // Display on LCD
  lcd.setCursor(0, 1);
  lcd.print(distance);
  lcd.print(" cm     "); // extra spaces to clear previous data

  delay(500);  
}