#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int trigPin = 6;
const int echoPin = 7;
const int buzzer = 8;

long duration;
int jarakCm, jarakInch;

void setup() {
  lcd.begin(12,2);
  lcd.backlight();  // Optional: to turn on the backlight

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzer, OUTPUT);
  
  Serial.begin(9600);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  jarakCm = duration * 0.034 / 2;
  jarakInch = duration * 0.0133 / 2;

  lcd.setCursor(0, 0);
  lcd.print("Jarak: ");
  lcd.print(jarakCm);
  lcd.print(" cm ");
  
  lcd.setCursor(0, 1);
  lcd.print("Jarak: ");
  lcd.print(jarakInch);
  lcd.print(" inch ");
  
  delay(500); // To slow down the display updates
  
  if (jarakCm <= 12) {
    tone(buzzer, 1030);
    delay(400);
    noTone(buzzer);
    delay(100);
  }

}