code.txt

#include<Keypad.h>
#include <Servo.h>
#include<LiquidCrystal.h>
LiquidCrystal lcd(13,12,16,17,18,19);
Servo Myservo;
const int buzzer = 15;
int pos, i;
int flag ;
const int green = 11;
const int red = 2;
const byte ROWS = 4; //four rows
const byte COLS = 4;
String password;	
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {10, 9, 8, 7}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {6, 5, 4, 3}; //connect to the column pinouts of the keypad

Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
void setup()
{
  lcd.begin(16,2);
  pinMode(green, OUTPUT);
  pinMode(red, OUTPUT);
  Myservo.attach(14);  // referring to analog pin A0
  pinMode(buzzer, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  Serial.println("Enter the custom password");// taking custom password from the user with the help of serial monitor
  while (Serial.available() == 0)
  { //Wait for user input
  }
  password = Serial.readString();
  digitalWrite(green,LOW);   // intially green and red both light are switched off
  digitalWrite(red,LOW);
  lcd.setCursor(0,0);
  lcd.print("enter 5 dig pin");
  lcd.setCursor(0,1);
  char arr[6];
  for (int j = 0; j < 3; j++) {
    digitalWrite(green,LOW);
    digitalWrite(red,LOW);
    flag = 0;
    for (i = 0; i < 5; i++)
    {
      arr[i] = '\0';
      while (arr[i] == '\0')
      {
        arr[i] = keypad.getKey();
      }
      delay(1);
      if(i==0)     //clearing second line of lcd from previous pin
      	{
        	lcd.setCursor(0,1);
        	lcd.print("     ");
        	lcd.setCursor(0,1);
      	}
      lcd.print(arr[i]);
    }
    for (i = 0; i < 5; i++)
    {
      if (arr[i] != password[i]){    
        flag = 1;
        lcd.setCursor(0,0);
        lcd.print("wrong password  ");  // displaying wrong password on entering wrong password
        delay(500);
        lcd.setCursor(0,0);
        lcd.print("           ");  // clearing previous line
        lcd.setCursor(0,0);
        lcd.print("enter 5 dig pin  ");
        lcd.setCursor(0,1);
      }
      delay(1);
    }
    if (flag == 0) //if password correct leave loop 
      break;
  }
  if (flag == 0)
  {
    lcd.setCursor(0,0);
    lcd.print("correct password");
    digitalWrite(green, LOW);  
    digitalWrite(red, LOW);
    digitalWrite(green, HIGH);  // if password entered is correct , green led will glow
    digitalWrite(red, LOW);
    delay(1000);
    for (pos = 0; pos <= 180; pos++){ //for movement of servo motor
      Myservo.write(pos);
      delay(15);
    }
    delay(500);
    for (pos = 180; pos >= 0; pos--) {
      Myservo.write(pos);
      delay(15);
    }
  }
  else
  {
    tone(buzzer, 1000); // Send 1KHz sound signal to piezo buzzer
    digitalWrite(red, HIGH);    //red led will glow
    digitalWrite(green, LOW);   // green will be switched off
    delay(1000);
    noTone(buzzer);
    delay(10000);   // locking the system for 10 minutes to avoid fake person from entering password again and again
  }
}