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

// Initialize the LCD, using the default I2C address 0x27
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Define pins
const int buttonPin = 8;  // Button input
const int ledPin = 9;     // LED output
const int buzzerPin = 10; // Buzzer output

bool stopRequested = false;  // Track if stop has been requested
bool lastButtonState = LOW;  // Last button state for debouncing
unsigned long lastDebounceTime = 0;
const unsigned long debounceDelay = 50;  // Debounce delay in milliseconds

void setup() {
  // Initialize LCD, LED, button, and buzzer
   lcd.begin(16, 2);
   lcd.backlight();
  
  pinMode(buttonPin, INPUT); // Button as input
  pinMode(ledPin, OUTPUT);   // LED as output
  pinMode(buzzerPin, OUTPUT); // Buzzer as output
  
  // Initial LCD message
  lcd.setCursor(0, 0);
  lcd.print("No Stop Request");
}

void loop() {
  // Read button state with debounce
  int buttonState = digitalRead(buttonPin);
  
  if (buttonState != lastButtonState) {
    lastDebounceTime = millis();
  }
  
  if ((millis() - lastDebounceTime) > debounceDelay) {
    // When button is pressed, toggle stop request
    if (buttonState == HIGH && !stopRequested) {
      stopRequested = true;
      requestStop();
    }
  }
  
  lastButtonState = buttonState;
  
  // Reset stop request if button is pressed again
  if (stopRequested && buttonState == LOW) {
    stopRequested = false;
    resetDisplay();
  }
}

void requestStop() {
  // Activate LED and buzzer
  digitalWrite(ledPin, HIGH);
  digitalWrite(buzzerPin, HIGH);
  delay(2000);  // Sound the buzzer for 500 ms
  digitalWrite(buzzerPin, LOW);
  
  // Display "Stop Requested" on LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Stop Requested");
   delay(5000);
} 

void resetDisplay() {
  // Turn off LED
  digitalWrite(ledPin, LOW);
  
  // Clear LCD and show default message
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("No Stop Request");
}