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

// LCD settings
LiquidCrystal_I2C lcd(0x27, 20, 4); // Adjust I2C address if necessary

// TCRT5000 and reset button pins
const int tcrt5000Pin = 2; // Digital pin for TCRT5000
const int resetButtonPin = 3; // Digital pin for reset button

int counter = 0;           // Count detected events
bool previousState = HIGH; // Previous state of the TCRT5000 sensor
const int counterLimit = 20; // Maximum count limit

void setup() {
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  
  // Display initial message
  lcd.setCursor(0, 0);
  lcd.print("TCRT5000 Counter:");
  lcd.setCursor(0, 1);
  lcd.print("Count: ");
  lcd.setCursor(7, 1);
  lcd.print(counter);
  
  // Initialize the pins
  pinMode(tcrt5000Pin, INPUT_PULLUP);
  pinMode(resetButtonPin, INPUT_PULLUP); // Use internal pull-up resistor

  // Start serial monitor for debugging
  Serial.begin(9600);
}

void loop() {
  // Read the current state of the sensor
  bool currentState = digitalRead(tcrt5000Pin);

  // Detect a transition from HIGH to LOW (light to dark) if below the limit
  if (previousState == HIGH && currentState == LOW && counter < counterLimit) {
    counter++; // Increment the counter

    // Update the LCD with the new count
    lcd.setCursor(7, 1);
    lcd.print("    "); // Clear old value
    lcd.setCursor(7, 1);
    lcd.print(counter);

    Serial.print("Line detected - Counter incremented to: ");
    Serial.println(counter);
  }

  // Check if the reset button is pressed
  if (digitalRead(resetButtonPin) == LOW) {
    counter = 0; // Reset the counter

    // Update the LCD
    lcd.setCursor(7, 1);
    lcd.print("    "); // Clear old value
    lcd.setCursor(7, 1);
    lcd.print(counter);

    Serial.println("Counter reset to zero");
    delay(200); // Debounce delay
  }

  // Update the previous state
  previousState = currentState;

  // Add a small delay to debounce the sensor
  delay(50);
}