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

LiquidCrystal_I2C lcd(0x27, 20, 4); // Initialize the LCD using the address 0x27 and size of 120x4
#define trigPin 9 // Arduino digital pin connected to the trigger pin of the ultrasonic sensor
#define echoPin 10 // Arduino digital pin connected to the echo pin of the ultrasonic sensor

void setup() {
  lcd.init(); // Initialize the LCD
  lcd.backlight(); // Turn on the backlight
  lcd.setBacklight(HIGH); // Turn on the backlight
  lcd.begin(20,4); // Initialize the LCD with 16 columns and 2 rows
  lcd.setCursor(0, 0); // Set the cursor to the first column and the first row
  lcd.print("God Is My Light"); // Print the heading text
  
  pinMode(trigPin, OUTPUT); // Set the trigger pin as an output
  pinMode(echoPin, INPUT); // Set the echo pin as an input
  
  Serial.begin(9600); // Initialize serial communication for debugging
}

void loop() {
  long duration, distance;
  
  float waterLevel;
  String waterStatus;

  // Clear the trigger pin and wait for a short delay
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  
  // Set the trigger pin to high for 10 microseconds to transmit the ultrasonic pulse
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Read the echo pin to measure the duration of the pulse and calculate the distance
  duration = pulseIn(echoPin, HIGH);
  distance = (duration * 0.0343) / 2; // Calculate the distance in cm (speed of sound is 0.0343 cm/microsecond)
  
  // Assuming tank height is 20 cm, calculate the water level in percentage
  waterLevel = 100 - (distance * 100 / 200);
  
  lcd.setCursor(0, 1); // Set the cursor to the first column and the second row
  lcd.print("Level: "); // Print the label
  
  if (waterLevel < 10) {
    waterStatus = "Empty Tank";
  } else if (waterLevel < 25) {
    waterStatus = "Low Water ";
  } else {
    waterStatus = String(waterLevel) + "%    ";
  }
  
  lcd.print(waterStatus); // Print the water level status
  
  delay(1000); // Delay for 1 second before the next reading
}