#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <NewPing.h>
#define TRIGGER_PIN 9
#define ECHO_PIN 10
#define LCD_ADDRESS 0x27
#define LCD_COLUMNS 16
#define LCD_ROWS 2
LiquidCrystal_I2C lcd(LCD_ADDRESS, LCD_COLUMNS, LCD_ROWS);
NewPing sonar(TRIGGER_PIN, ECHO_PIN);
void setup() {
  lcd.begin(LCD_COLUMNS, LCD_ROWS);
  lcd.backlight();
  lcd.print("Ultrasonic Sensor");
  delay(2000);
  lcd.clear();
}
void loop() {
  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  int distance = readDistance();
  
  if (distance >= 0) {
    lcd.setCursor(0, 1);
    lcd.print(distance);
    lcd.print(" cm");
  } else {
    lcd.setCursor(0, 1);
    lcd.print("Error");
  }
  delay(1000);
  lcd.clear();
}
int readDistance() {
  delay(50);
  unsigned int distance = sonar.ping_cm();
  
  if (distance == 0) {
    return -1; // Error reading distance
  } else {
    return distance;
  }
}