// Simple Button, Buzzer, and LED Interface
const int buttonPin = 2;    // Button pin
const int buzzerPin = 3;   // Buzzer pin
const int ledPin = 4;     // LED pin

int ledState = LOW;        // LED state

void setup() {
    pinMode(buttonPin, INPUT_PULLUP);  // Button setup
    pinMode(buzzerPin, OUTPUT);        // Buzzer setup
    pinMode(ledPin, OUTPUT);          // LED setup
}

void loop() {
    // Check if button is pressed
    if (digitalRead(buttonPin) == LOW) {
        // Toggle LED
        ledState = !ledState;
        digitalWrite(ledPin, ledState);
        
        // Turn on buzzer for 350ms
        digitalWrite(buzzerPin, HIGH);
        delay(350);
        digitalWrite(buzzerPin, LOW);
        
        // Wait a bit to avoid multiple triggers
        delay(200);
    }
}

// Simple LED Blinking Program
const int ledPin = 13;    // LED connected to pin 13

void setup() {
    pinMode(ledPin, OUTPUT);  // Set LED pin as output
}

void loop() {
    digitalWrite(ledPin, HIGH);  // Turn LED ON
    delay(2000);                    // Wait for 2 seconds
    
    digitalWrite(ledPin, LOW);   // Turn LED OFF
    delay(2000);                    // Wait for 2 seconds
}

// Traffic Light Simulation Program
const int redPin = 2;     // Red LED pin
const int yellowPin = 3;  // Yellow LED pin
const int greenPin = 4;   // Green LED pin

void setup() {
    pinMode(redPin, OUTPUT);     // Red LED setup
    pinMode(yellowPin, OUTPUT);  // Yellow LED setup
    pinMode(greenPin, OUTPUT);   // Green LED setup
}

void loop() {
    // Red Light - ON for 5 seconds
    digitalWrite(redPin, HIGH);
    digitalWrite(yellowPin, LOW);
    digitalWrite(greenPin, LOW);
    delay(5000);
    
    // Yellow Light - ON for 2 seconds
    digitalWrite(redPin, LOW);
    digitalWrite(yellowPin, HIGH);
    digitalWrite(greenPin, LOW);
    delay(2000);
    
    // Green Light - ON for 5 seconds
    digitalWrite(redPin, LOW);
    digitalWrite(yellowPin, LOW);
    digitalWrite(greenPin, HIGH);
    delay(5000);
    
    // Cycle repeats automatically
}

// Simple LCD Display Program
#include <LiquidCrystal.h>

// LCD pin connections
const int rs = 12;    // RS pin
const int en = 11;    // Enable pin
const int d4 = 5;     // D4 pin
const int d5 = 4;     // D5 pin
int d6 = 3;     // D6 pin
int d7 = 2;     // D7 pin

// Create LCD object
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {
    lcd.begin(16, 2);  // 16 columns, 2 rows
    lcd.print("QuitExams");      // Show text on first line
}

void loop() {
    lcd.setCursor(0, 1);  // Go to second line
    lcd.print(millis() / 1000);  // Show seconds
    delay(1000);  // Wait 1 second
}