Crack Me If You Can

// Created by Surya Skywalker. This code will be used in the locker. when the correct card is swiped, light goes gren and door opens and when swiped a second time, door closes and light goes
// to blue. when wrong card is swiped, ligh goes red and buzzer beeps. 

#include <SPI.h>
#include <MFRC522.h>
#include <Servo.h>

#define SS_PIN 10
#define RST_PIN 9
#define Buzzer 8 // Pin 3 connected to + pin of the Buzzer

Servo myservo;  // create servo object to control a servo
// twelve servo objects can be created on most boards
MFRC522 mfrc522(SS_PIN, RST_PIN);   // Create MFRC522 instance.

int pos = 0;    // variable to store the servo position
int num = 0;
int redPin = 2;
int greenPin = 4;
int bluePin = 7;
int counter = 0;
const int buzzerPin = 8;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);   // Initiate a serial communication
  SPI.begin();      // Initiate  SPI bus
  mfrc522.PCD_Init();   // Initiate MFRC522
  Serial.println("Approximate your card to the reader...");
  Serial.println();
  myservo.attach(3);  // attaches the servo on pin 9 to the servo object
  myservo.write(0); //Set the servo at position 0
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
  setColor(0, 0, 225);  // blue
  pinMode(Buzzer, OUTPUT); // Set buzzer pin to an Output pin
  digitalWrite(Buzzer, LOW); // Buzzer Off at startup

}

void loop() {
  // put your main code here, to run repeatedly:
  // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent()) 
  {
    return;
  }
  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial()) 
  {
    return;
  }
  //Show UID on serial monitor
  Serial.print("UID tag :");
  String content= "";
  byte letter;
  for (byte i = 0; i < mfrc522.uid.size; i++) 
  {
     Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
     Serial.print(mfrc522.uid.uidByte[i], HEX);
     content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));
     content.concat(String(mfrc522.uid.uidByte[i], HEX));
  }
  Serial.println();
  Serial.print("Message : ");
  content.toUpperCase();
  if (content.substring(1) == "4A 31 07 85") //change here the UID of the card/cards that you want to give access
  {
    if (num % 2 == 0)
    {
      setColor(0, 225, 0); // Green
      myservo.write(180);
      Serial.println("Authorized access");
      Serial.println();
    }
    else  {
      Serial.println("Locking...");
      myservo.write(0);
      delay(750);
      Serial.println("Message : Locked");
      Serial.println();
      setColor(0, 0, 225); // Blue
    }
    num = num + 1;
    delay(3000);
  }
 
  else   {
    setColor(225, 0, 0); // Red
    Serial.println("Access denied");
    Serial.println();
    beep(1000,10000);
    setColor(0, 0, 225); // Blue
  }
}

void setColor(int red, int green, int blue)
{
  #ifdef COMMON_ANODE
    red = 255 - red;
    green = 255 - green;
    blue = 255 - blue;
  #endif
  analogWrite(redPin, red);
  analogWrite(greenPin, green);
  analogWrite(bluePin, blue);  
}

void beep(int note, int duration)
{
  //Play tone on buzzerPin
  tone(buzzerPin, note);
  delay(duration);
  //Stop tone on buzzerPin
  noTone(buzzerPin);
 
  delay(50);
 
  //Increment counter
  counter++;
}