#include <Servo.h>
#include "HX711.h"
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Pin definitions
#define LDR_PIN             8    // LDR module digital output connected to pin 8
#define TRIG_PIN            9    // HC-SR04 Trigger pin
#define ECHO_PIN            10   // HC-SR04 Echo pin
#define LOADCELL_DOUT_PIN   3    // HX711 Data pin
#define LOADCELL_SCK_PIN    2    // HX711 Clock pin
#define BUZZER_PIN          4    // Pin for Active Buzzer
#define COIN_DISPENSER_PIN  11   // Pin for coin dispenser servo (servo pin 11)
#define GATE_SERVO_PIN      5    // Pin for gate servo (servo pin 5)
#define LASER_PIN           7    // Pin for Laser Diode (with external resistor)
#define LOAD_CELL_SERVO_PIN 6    // Pin for load cell servo (servo pin 6)

// Servo setup for load cell, coin dispenser, and gate
Servo loadCellServo;     // Servo for load cell (plastic bottle dispenser)
Servo coinDispenser;     // Servo for DIY coin dispenser
Servo gateServo;         // Servo for gate

const int moveAngle = 20; // Angle to move coin dispenser and gate servo

// HX711 setup for load cell
HX711 scale;
float calibration_factor = -690; // Adjust this calibration factor based on your scale

// Variables for distance and LDR state
long duration;
int distance;
int ldrState;      // Store the LDR state (HIGH or LOW)
float weight;      // Variable to store weight reading

// Counter for plastic bottles
int plasticCounter = 0;  // Count number of plastic bottles detected

// I2C LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);  // Change the address (0x27) if needed

void setup() {
  Serial.begin(9600);  // Start serial communication

  // Initialize pin modes
  pinMode(LDR_PIN, INPUT);          // Set the LDR pin as input
  pinMode(TRIG_PIN, OUTPUT);        // Set the Trigger pin as output
  pinMode(ECHO_PIN, INPUT);         // Set the Echo pin as input
  pinMode(BUZZER_PIN, OUTPUT);      // Set the Buzzer pin as output
  pinMode(LASER_PIN, OUTPUT);       // Set the Laser pin as output

  // Turn on the laser diode (ensure an external resistor is used)
  digitalWrite(LASER_PIN, HIGH);

  // Initialize HX711 scale
  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
  scale.set_scale(calibration_factor);
  scale.tare(); // Reset the scale to 0

  // Initialize servos
  loadCellServo.attach(LOAD_CELL_SERVO_PIN);    // Attach the load cell servo to pin 6
  coinDispenser.attach(COIN_DISPENSER_PIN);      // Attach the coin dispenser servo to pin 11
  gateServo.attach(GATE_SERVO_PIN);              // Attach the gate servo to pin 5

  // Initialize servos to their neutral positions
  loadCellServo.write(0);       // Start at 0 degrees for load cell servo
  coinDispenser.write(90);      // Set coin dispenser to neutral position
  gateServo.write(90);          // Set gate servo to neutral position

  // Initialize the I2C LCD
  lcd.begin(16, 2);              // Initialize the LCD with 16 columns and 2 rows
  lcd.clear();                   // Clear the LCD screen
  lcd.setCursor(0, 0);           // Set cursor to the top left of the screen
  lcd.print("Plastic Counter");   // Display initial message
  delay(2000);                   // Wait for 2 seconds

  // Turn on the LCD backlight
  lcd.backlight();
  Serial.println("Plastic Detection & Weight Measurement System Started");
}

void loop() {
  // Read the LDR module state (HIGH or LOW) from the digital output
  ldrState = digitalRead(LDR_PIN);

  // Measure distance using the ultrasonic sensor
  digitalWrite(TRIG_PIN, LOW);        // Ensure TRIG is low initially
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);       // Send trigger pulse
  delayMicroseconds(10);        
  digitalWrite(TRIG_PIN, LOW);        // End trigger pulse
  duration = pulseIn(ECHO_PIN, HIGH); // Read the echo pulse duration

  // Calculate distance in cm
  distance = duration * 0.034 / 2;

  // Read the weight from the HX711 scale
  weight = scale.get_units(10); // Average over 10 readings for stability

  // Display information on Serial Monitor
  Serial.print("LDR State: ");
  if (ldrState == LOW) {
    Serial.print("Laser Detected ");
  } else {
    Serial.print("Laser Not Detected ");
  }

  // Display distance in cm
  Serial.print("| Distance: ");
  Serial.print(distance);
  Serial.print(" cm | ");
  
  // Display weight in grams
  Serial.print("Weight: ");
  Serial.print(weight);
  Serial.println(" g");

  // Logic to detect plastic, check weight (10 to 50 grams), and distance
  if (ldrState == LOW && distance < 7 && weight >= 9 && weight <= 30) {
    // All conditions are met for plastic detection
    Serial.println("Plastic Detected");
    plasticCounter++;  // Increment the plastic bottle counter

    // Move the gate servo backward to open the gate
  

    // Rotate the load cell servo for bottle dispensing
    loadCellServo.write(60);  // Rotate to 180 degrees to dispense
    delay(1000);                // Wait for 1 second

    gateServo.write(90 - (moveAngle -9));  // Move backward by moveAngle (e.g., 70 degrees)
    delay(1000);       
                    // Wait for the servo to move
    loadCellServo.write(0);     // Return to 0 degrees (original position)
    delay(1000);                // Wait for 1 second

    // Move the gate servo forward to close the gate
    gateServo.write(90 + (moveAngle -8));  // Move forward by moveAngle (e.g., 110 degrees)
    delay(1000);                       // Wait for the servo to move back
    gateServo.write(90);               // Return to neutral position
    delay(500);                        // Short delay

    // Move coin dispenser when counter reaches 3
    if (plasticCounter >= 3) {
      // Display "Dispensing Coin" before moving the coin dispenser
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Dispensing Coin");
      
      // Move the coin dispenser
      coinDispenser.write(90 + moveAngle);  // Move forward by moveAngle (e.g., 110 degrees)
      delay(1000);                    // Wait for the servo to move
      // Move the servo backward (counter-clockwise) by the same moveAngle
      coinDispenser.write(90 - moveAngle);  // Move back by moveAngle (e.g., 70 degrees)
      delay(1000); 
      coinDispenser.write(90);              // Return to neutral position
      delay(1000); 

      plasticCounter = 0;       // Reset the counter after releasing a coin
    }

    // Show on LCD that plastic was detected
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Valid");
    lcd.setCursor(0, 1);
    lcd.print("Plastic Bottle");

    // Sound the buzzer once for valid plastic
    tone(BUZZER_PIN, 1000, 500);  // Buzzer sounds for 500ms at 1000Hz

    delay(2000);  // Display this for 2 seconds before resetting

  } 
  else if (ldrState == HIGH && distance < 7 && weight >= 9 && weight <= 30) {
    // Laser not detected, but distance and weight are valid
    Serial.println("Not Plastic");
    
    // Show on LCD that object is not plastic
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Invalid");
    lcd.setCursor(0, 1);
    lcd.print("Remove Object");

    // Sound the buzzer repeatedly for invalid plastic
    while (ldrState == HIGH && distance < 7 && weight >= 9 && weight <= 30) {
      tone(BUZZER_PIN, 1000, 500);  // Buzzer sounds for 500ms at 1000Hz
      delay(500);                     // Wait for 500ms before sounding again
      // Recheck sensor states
      ldrState = digitalRead(LDR_PIN);        // Recheck LDR state
      digitalWrite(TRIG_PIN, LOW);             // Trigger low
      delayMicroseconds(2);
      digitalWrite(TRIG_PIN, HIGH);            // Send trigger pulse
      delayMicroseconds(10);        
      digitalWrite(TRIG_PIN, LOW);             // End trigger pulse
      duration = pulseIn(ECHO_PIN, HIGH);      // Read the echo pulse duration
      distance = duration * 0.034 / 2;         // Recalculate distance
      weight = scale.get_units(10);             // Recheck weight
    }

    delay(2000);  // Display this for 2 seconds before resetting

  } 
  else {
    // No valid object detected
    Serial.println("No Object Detected");
    
    // Show on LCD the current counter and insert bottle message
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Counter: ");
    lcd.print(plasticCounter);  // Display the current plastic counter
    lcd.setCursor(0, 1);
    lcd.print("Insert Bottle");

    // Turn off the buzzer if no object detected
    noTone(BUZZER_PIN);  // Stop buzzer sound
  }

  // Reset counter if it reaches 3
  if (plasticCounter >= 3) {
    plasticCounter = 0;  // Reset the counter
  }

  delay(30);  // Small delay for stability
}