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

// Inisialisasi LCD dengan alamat I2C 0x27 dan dimensi 20x4
LiquidCrystal_I2C lcd(0x27, 20, 4);


 int trigPin = 3;
 int echoPin = 2;

 int redLedPin = 10;
 int yellowLedPin = 9;
 int greenLedPin = 8;

void setup() {
  lcd.begin(20,4);
  lcd.backlight();

  pinMode(redLedPin, OUTPUT);
  pinMode(yellowLedPin, OUTPUT);
  pinMode(greenLedPin, OUTPUT);

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2); //delay selama 2 mikrodetik
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10); 
  digitalWrite(trigPin, LOW);
  
  // Mengukur durasi pada pin echo
  long duration = pulseIn(echoPin, HIGH);
  
  
  float distance = duration * 0.034 / 2;
  
  lcd.setCursor(0, 0); 
  lcd.print("Ketinggian Air: "); 
  lcd.setCursor(0, 1); 
  lcd.print(distance); 
  lcd.print(" cm"); 

  if (distance <= 150) {
    digitalWrite(greenLedPin, LOW);
    digitalWrite(yellowLedPin, LOW);
    digitalWrite(redLedPin, HIGH);
  } else if (distance >150 && distance  <= 300) {
    digitalWrite(greenLedPin, LOW);
    digitalWrite(yellowLedPin, HIGH);
    digitalWrite(redLedPin, LOW);
  } else if (distance >300 && distance <=400) {
    digitalWrite(greenLedPin, HIGH);
    digitalWrite(yellowLedPin, LOW);
    digitalWrite(redLedPin, LOW);
  }
  
  delay(500); 
}