#include "LiquidCrystal_I2C.h"

#define ECHO_PIN 2
#define TRIG_PIN 3
#define Merah 6
#define Kuning 5
#define Hijau 4

float X=400/397.63;
LiquidCrystal_I2C lcd(0x27,20,4);// set the LCD address to 0x27 for a 20 chars and 4 line display


void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(Merah, OUTPUT);
  pinMode(Kuning, OUTPUT);
  pinMode(Hijau, OUTPUT);
  digitalWrite(Hijau, LOW);
  digitalWrite(Kuning, LOW);
  digitalWrite(Merah, LOW);
  lcd.init(); // initialize the lcd
  // Print a message to the LCD.
  lcd.backlight();

}

void loop() {
  //Generate ultrasonic signal
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  //Read ultrasonic signal
  int duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.034 * X / 2;

  Serial.print("Jarak: ");
  Serial.print(distance);
  Serial.println(" CM");

  //if(distance < 50) // pakai formula bertingkat
  if(distance > 0 && distance < 50) // pakai formula rentang
  {
    digitalWrite(Hijau, LOW);
    digitalWrite(Kuning, LOW);
    Serial.println("Merah (Bahaya!!!)");
    digitalWrite(Merah, HIGH);
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Tinggi Air: ");
    lcd.print(distance);
    lcd.setCursor(0,1);
    lcd.println("Status: Bahaya!!!");
  }
  //else if (distance < 150) // pakai formula bertingkat
  else if (distance >50 && distance < 150) // pakai formula rentang
  {
    digitalWrite(Hijau, LOW);
    digitalWrite(Merah, LOW);
    Serial.println("Kuning (Waspada)");
    digitalWrite(Kuning, HIGH);
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Tinggi Air: ");
    lcd.print(distance);
    lcd.setCursor(0,1);
    lcd.println("Status: Waspada");
  }
  else 
  {
    digitalWrite(Kuning, LOW);
    digitalWrite(Merah, LOW);
    Serial.println("Hijau (Normal)");
    digitalWrite(Hijau, HIGH);
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Tinggi Air: ");
    lcd.print(distance);
    lcd.setCursor(0,1);
    lcd.println("Status: Normal");
  }

  delay(500);
}