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	- Project: "Infrared Timer"
	- Source Code compiled for: Arduino Uno
	- Source Code created on: 2024-02-20 11:41:57

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/****** SYSTEM REQUIREMENTS *****/
/****** SYSTEM REQUIREMENT 1 *****/
	/* The project must control a timer that starts when */
	/* the infrared sensor is in a low active state and */
	/* stops when the sensor returns to a low active */
	/* state. The timer must be displayed on the LCD */
	/* screen. */
/****** SYSTEM REQUIREMENT 2 *****/
	/* The timer state should be handled using a state */
	/* machine. Furthermore, an explicit function called */
	/* 'resetTimer' needs to be implemented to reset the */
	/* counter and state of the state machine. */
/****** END SYSTEM REQUIREMENTS *****/

/****** DEFINITION OF LIBRARIES *****/
#include <Wire.h>
#include <LiquidCrystal_I2C.h> //https://github.com/marcoschwartz/LiquidCrystal_I2C
#include <EasyButton.h> //https://github.com/evert-arias/EasyButton

/****** SYSTEM REQUIREMENTS *****/
/****** SYSTEM REQUIREMENT 1 *****/
  /* The project must control a timer that starts when */
  /* the infrared sensor is in a low active state and */
  /* stops when the sensor returns to a low active */
  /* state. The timer must be displayed on the LCD */
  /* screen. */
/****** SYSTEM REQUIREMENT 2 *****/
  /* The timer state should be handled using a state */
  /* machine. Furthermore, an explicit function called */
  /* 'resetTimer' needs to be implemented to reset the */
  /* counter and state of the state machine. */
/****** END SYSTEM REQUIREMENTS *****/

/****** FUNCTION PROTOTYPES *****/
void setup(void);
void loop(void);
void resetTimer(void);

/***** DEFINITION OF DIGITAL INPUT PINS *****/
const uint8_t infraredSensor_PIN_D2 = 2;

/***** DEFINITION OF I2C PINS *****/
const uint8_t lcd_I2C_PIN_SDA_A4 = A4;
const uint8_t lcd_I2C_PIN_SCL_A5 = A5;
const uint8_t lcd_I2C_SLAVE_ADDRESS = 39;

/****** DEFINITION OF LIBRARIES CLASS INSTANCES*****/
LiquidCrystal_I2C lcd(lcd_I2C_SLAVE_ADDRESS, 16, 2); // Initialize the LiquidCrystal_I2C object
EasyButton button(infraredSensor_PIN_D2); // Initialize the EasyButton object

// Timer variables
unsigned long startTime = 0;
unsigned long elapsedTime = 0;
bool timerRunning = false;

enum TimerState
{
  IDLE,
  RUNNING
};

TimerState timerState = IDLE;

void resetTimer()
{
  startTime = 0;
  elapsedTime = 0;
  timerRunning = false;
  timerState = IDLE;
}

void setup(void)
{
  // put your setup code here, to run once:

  pinMode(infraredSensor_PIN_D2, INPUT_PULLUP);

  lcd.begin(16, 2); // Initialize the LCD with 16 columns and 2 rows
  lcd.backlight(); // Turn on the backlight

  lcd.print("Hello, Arduino!"); // Print a message on the LCD

  // Initialize the EasyButton object
  button.begin();

  // Attach button press event handler
  button.onPressed(buttonPressed);
}

void loop(void)
{
  // put your main code here, to run repeatedly:

  // Check if the button is pressed
  button.read();

  // Check if the infrared sensor is in a low active state
  if (digitalRead(infraredSensor_PIN_D2) == LOW)
  {
    // Check if the timer is not already running
    if (!timerRunning)
    {
      // Start the timer
      startTime = millis();
      timerRunning = true;
      timerState = RUNNING;
    }
  }
  else
  {
    // Check if the timer is running
    if (timerRunning)
    {
      // Stop the timer and calculate the elapsed time
      elapsedTime = millis() - startTime;
      timerRunning = false;
      timerState = IDLE;
    }
  }

  // Display the timer on the LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Timer: ");
  lcd.print(elapsedTime);

  delay(100); // Delay for stability
}

void buttonPressed()
{
  // Reset the timer when the button is pressed
  resetTimer();
}