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

LiquidCrystal_I2C lcd(0x27, 16, 2); // Alamat I2C LCD: 0x27, 16 kolom x 2 baris

#define trigPin 7
#define echoPin 8
#define greenLED 12
#define yellowLED 11
#define redLED 10

void setup() {
  Serial.begin(9600);
  lcd.init(); // Inisialisasi LCD
  lcd.backlight(); // Nyalakan backlight
  
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(redLED, OUTPUT);
}

void loop() {
  long duration;
  float distance_cm;
  
  digitalWrite(trigPin, LOW);  
  delayMicroseconds(2); 
  
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10); 
  digitalWrite(trigPin, LOW);
  
  duration = pulseIn(echoPin, HIGH);
  
  distance_cm = (float)duration * 0.034 / 1.99; // Menghitung jarak
  
  lcd.clear(); // Bersihkan layar
  
  if (duration == 0) {
    lcd.print("Tidak ada objek");
    Serial.println("Tidak ada objek");
  } else if (distance_cm > 15) {
    lcd.print("Jarak: ");
    lcd.print(distance_cm, 2); // Menampilkan hanya 2 angka di belakang koma
    lcd.print(" cm");
    
    Serial.print("Jarak: ");
    Serial.print(distance_cm);
    Serial.println(" cm");

    digitalWrite(greenLED, HIGH); // Lampu hijau menyala
    digitalWrite(yellowLED, LOW); // Lampu kuning mati
    digitalWrite(redLED, LOW); // Lampu merah mati
  } else if (distance_cm >= 5 && distance_cm <= 15) {
    lcd.print("Jarak: ");
    lcd.print(distance_cm, 2);
    lcd.print(" cm");
    
    Serial.print("Jarak: ");
    Serial.print(distance_cm);
    Serial.println(" cm");

    digitalWrite(greenLED, LOW); // Lampu hijau mati
    digitalWrite(yellowLED, HIGH); // Lampu kuning menyala
    digitalWrite(redLED, LOW); // Lampu merah mati
  } else {
    lcd.print("Jarak: ");
    lcd.print(distance_cm, 2);
    lcd.print(" cm");
    
    Serial.print("Jarak: ");
    Serial.print(distance_cm);
    Serial.println(" cm");

    digitalWrite(greenLED, LOW); // Lampu hijau mati
    digitalWrite(yellowLED, LOW); // Lampu kuning mati
    digitalWrite(redLED, HIGH); // Lampu merah menyala
  }
  
  delay(500); // Tunggu sebentar sebelum mengukur lagi
}