#include <LiquidCrystal_I2C.h>
#include <Servo.h>

// LCD module configuration
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Ultrasonic sensor 1 pins
const int trigPin1 = 12;
const int echoPin1 = 13;

// Ultrasonic sensor 2 pins
const int trigPin2 = 10;
const int echoPin2 = 11;

// Buzzer pin
const int buzzerPin = 5;

// Servo motor pin
const int servoPin = 9;
Servo servoMotor;

// LED pin
const int ledPin = 4;

// Feeding parameters
const int distanceThresholdServo = 100;  // Distance threshold for servo control in cm
const int distanceThresholdLCD = 20;    // Distance threshold for LCD display in cm
const int servoOpenAngle = 90;          // Angle to open the feeding mechanism
const int servoClosedAngle = 0;         // Angle to close the feeding mechanism
const int feedingDuration = 2000;       // Duration for which the feeding mechanism stays open in milliseconds

// Variables to store previous distance values
int previousDistance1 = 0;

void setup() {
  // Initialize LCD
  lcd.init();               // initialize the lcd
  lcd.backlight();          // open the backlight

  // Initialize ultrasonic sensor 1 pins
  pinMode(trigPin1, OUTPUT);
  pinMode(echoPin1, INPUT);

  // Initialize ultrasonic sensor 2 pins
  pinMode(trigPin2, OUTPUT);
  pinMode(echoPin2, INPUT);

  // Initialize buzzer pin
  pinMode(buzzerPin, OUTPUT);

  // Initialize servo motor
  servoMotor.attach(servoPin);

  // Initialize LED pin
  pinMode(ledPin, OUTPUT);

  // Print initial message on LCD
  lcd.setCursor(0, 0);
  lcd.print("Smart Feeder");
}

void loop() {
  // Measure distance using ultrasonic sensor 1
  long duration1, distance1;
  digitalWrite(trigPin1, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin1, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin1, LOW);
  duration1 = pulseIn(echoPin1, HIGH);
  distance1 = (duration1 / 2) / 29.1;

  // Update LCD with distance from ultrasonic sensor 1 if it has changed
  if (distance1 != previousDistance1) {
    updateLCD(distance1);
    previousDistance1 = distance1;
  }

  // Check if distance is less than the threshold and activate the buzzer
  if (distance1 <= distanceThresholdLCD) {
    activateBuzzer();
  } else {
    deactivateBuzzer();
  }

  // Measure distance using ultrasonic sensor 2
  long duration2, distance2;
  digitalWrite(trigPin2, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin2, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin2, LOW);
  duration2 = pulseIn(echoPin2, HIGH);
  distance2 = (duration2 / 2) / 29.1;

  // Check if feeding is required for servo control
  if (distance2 <= distanceThresholdServo) {
    feed();
  }
}

void updateLCD(int distance) {
  // Clear LCD and print distance value
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print(" cm");
}

void activateBuzzer() {
  digitalWrite(buzzerPin, HIGH);
}

void deactivateBuzzer() {
  digitalWrite(buzzerPin, LOW);
}

void feed() {
  // Activate the feeding mechanism
  servoMotor.write(servoOpenAngle);
  digitalWrite(ledPin, HIGH);

  // Wait for the feeding duration
  delay(feedingDuration);

  // Deactivate the feeding mechanism
  servoMotor.write(servoClosedAngle);
  digitalWrite(ledPin, LOW);
}