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

const int trigPin = 5;
const int echoPin = 18;

const int lowLED = 25;
const int midLED = 26;
const int highLED = 27;

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup(){
  Serial.begin(115200);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  pinMode(lowLED, OUTPUT);
  pinMode(midLED, OUTPUT);
  pinMode(highLED, OUTPUT);

  lcd.init();
  lcd.backlight();
}

void loop(){
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH);

  float distance = (duration * 0.0343) / 2;

  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Water Level: ");
  lcd.setCursor(0,1);
  lcd.print(distance);
  lcd.print(" cm");

  if (distance >30){
    digitalWrite(lowLED, HIGH);
    digitalWrite(midLED, LOW);
    digitalWrite(highLED, LOW);
  } else if (distance <= 30 && distance > 15){
    digitalWrite(lowLED, LOW);
    digitalWrite(midLED, HIGH);
    digitalWrite(highLED, LOW);
  } else if (distance <= 15){
    digitalWrite(lowLED, LOW);
    digitalWrite(midLED, LOW);
    digitalWrite(highLED, HIGH);
  }
  delay(1000);
}