#define button1 2
#define button2 3
#define button3 4
#define button4 9
#define buzzerPin 5
#define LED1 6
#define LED2 7
#define LED3 8
#define LED4 10
#define uint8 unsigned char 
uint8 flag =0; 
uint8 b1State,b2State,b3State,b4State =0;

void setup()
{
  
  pinMode(buzzerPin, OUTPUT);
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(LED4, OUTPUT);
  pinMode(button1, INPUT_PULLUP);
  pinMode(button2, INPUT_PULLUP);
  pinMode(button3, INPUT_PULLUP);
  pinMode(button4, INPUT_PULLUP);
  digitalWrite(LED1, LOW);
  digitalWrite(LED2, LOW);
  digitalWrite(LED3, LOW);
  digitalWrite(LED4, LOW);
}
void loop()
{
  digitalWrite(LED1, LOW);
  digitalWrite(LED2, LOW);
  digitalWrite(LED3, LOW);
  digitalWrite(LED4, LOW);
  b4State = digitalRead(button4);
  if (b4State == 0)
  {
    if (b4State == 0)
      // In Engineering Management And Science             Page | 1640 INTERNATIONAL JOURNAL OF PROGRESSIVE RESEARCH IN ENGINEERING MANAGEMENT AND SCIENCE (IJPREMS) (Int Peer Reviewed Journal) e-ISSN : 2583-1062 Impact Factor : 7.001 www.ijprems.com [email protected] Vol. 04, Issue 11, November 2024, pp : 1638-1642
    {
      flag = 1;
      digitalWrite(LED4, HIGH);
      delay(200);
    }
  }
  if (1 == flag)
  {
    b1State = digitalRead(button1);
    b2State = digitalRead(button2);
    b3State = digitalRead(button3);
    if (b1State == 0)
    {
      flag = 0;
      digitalWrite(LED4, LOW);
      Alarm();
      digitalWrite(LED1, HIGH);
      digitalWrite(LED2, LOW);
      digitalWrite(LED3, LOW);
      while (digitalRead(button4));
    }
    if (b2State == 0)
    {
      flag = 0;
      digitalWrite(LED4, LOW);
      Alarm();
      digitalWrite(LED1, LOW);
      digitalWrite(LED2, HIGH);
      digitalWrite(LED3, LOW);
      while (digitalRead(button4));
    }
    if (b3State == 0)
    {
      flag = 0;
      digitalWrite(LED4, LOW);
      Alarm();
      digitalWrite(LED1, LOW);
      digitalWrite(LED2, LOW);
      digitalWrite(LED3, HIGH);
      while (digitalRead(button4));
    }
  }
}
void Alarm ()
{ for (int i = 0; i < 100; i++)
  {
    digitalWrite(buzzerPin, HIGH);
    delay(2);
    digitalWrite(buzzerPin, LOW);
    delay(2);
  }
}