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

LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 column and 2 rows

const int trigPin = 12; // Ultrasonic sensor trigger pin
const int echoPin = 14; // Ultrasonic sensor echo pin
const int ledPin = 21;   // LED pin
const int relayPin = 27; // Relay control pin

const int maximumDistance = 400; // Maximum distance in centimeters

void setup() {
  Serial.begin(115200);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(relayPin, OUTPUT);
lcd.init();  
  //lcd.begin(16, 2);
  lcd.backlight();
}

void loop() {
  float distance = getDistance();
  int waterLevel = map(400-distance, 0, maximumDistance, 100, 0);
  
  displayWaterLevel(waterLevel);
  
  if (waterLevel < 20) { // Adjust the threshold as needed
    digitalWrite(ledPin, HIGH);
    digitalWrite(relayPin, HIGH); // Turn on the relay
  } else {
    digitalWrite(ledPin, LOW);
    digitalWrite(relayPin, LOW); // Turn off the relay
  }

  delay(1000); // Adjust delay as needed
}

float getDistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  return pulseIn(echoPin, HIGH) * 0.0343 / 2;
}

void displayWaterLevel(int level) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Water Level: ");
  lcd.print(level);
  lcd.print("%");
}