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

#define trigPin 9      // Pin connected to the trigger input of the ultrasonic sensor
#define echoPin 10     // Pin connected to the echo output of the ultrasonic sensor
#define buzzerPin 7    // Pin connected to the positive input of the buzzer
#define relayPin 8     // Pin connected to the relay module

int waterLevelThreshold = 50; // Adjust this value according to your setup and desired water level

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

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(relayPin, OUTPUT);
}

void loop() {
  long duration, distance;

  // Trigger ultrasonic sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the echo pulse
  duration = pulseIn(echoPin, HIGH);

  // Calculate distance in centimeters
  distance = (duration / 2) * 0.0343;

  // Display distance on LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Water Level: ");
  lcd.print(distance);
  lcd.print(" cm");

  // Check water level
  if (distance < waterLevelThreshold) {
    // Water level is below threshold, activate buzzer and relay
    digitalWrite(buzzerPin, HIGH);
    digitalWrite(relayPin, HIGH);
    lcd.setCursor(0, 1);
    lcd.print("Low! Buzzer On");
    Serial.println("Water level is low! Buzzer and relay activated.");
  } else {
    // Water level is above threshold, deactivate buzzer and relay
    digitalWrite(buzzerPin, LOW);
    digitalWrite(relayPin, LOW);
    lcd.setCursor(0, 1);
    lcd.print("                ");
  }

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