Arduino Door Strike

//Library Imports
#include <SoftwareSerial.h>
#include <EEPROM.h>
#define doorPin 6

//START USER EDIT
const int SOFT_RX = 3;
const int SOFT_TX = 10;
const int CARD_SIZE = 4;
byte MASTER_ADD[4] = {0x12,0x34,0x56,0x78}; //change these key values to match your tag
byte MASTER_DEL[4] = {0xAB,0xCD,0xEF,0x12};
//END USER EDIT

SoftwareSerial rfid(SOFT_TX, SOFT_RX); //pin10 Rx, pin3 Tx, mega doesn't support change interrupts on pin 2
byte readCard[CARD_SIZE];
byte storedCard[CARD_SIZE];
boolean match = false;
boolean programMode = false;

void setup()
{
  pinMode(doorPin, OUTPUT);
  Serial.begin(9600);
  Serial.println("Welcome to Chuck's RFID access control:");
  // set the data rate for the SoftwareSerial port
  rfid.begin(9600);
  delay(10);
  startAutoScan();
}

void loop() // run over and over
{
  if(rfid.available() > 0) {
    getID();
    //printID();
    if (programMode)
    {
      if ( !checkTwo(readCard,MASTER_ADD) )
      {
        writeID(readCard);
        Serial.println("New key added");
        programMode = false;
      }
    }
    else if ( checkTwo(readCard,MASTER_ADD) )
    {
      programMode = true;
      Serial.println("Detected MASTER ADD key");
      Serial.println("Swipe key you wish to add...");
    }
    else if ( checkTwo(readCard,MASTER_DEL) )
    {
      if (EEPROM.read(0) > 0) { EEPROM.write(0,0); }
      Serial.println("Detected MASTER DEL key");
      Serial.println("All guest keys disabled");
    }
    else if ( findID(readCard) )
    {
      Serial.println("Detected VALID key");
      Serial.println("Open Door");
      openDoor(2);
    }
    else
    {
      Serial.println("ID not valid");
    }
  }
}


void startAutoScan()
{
  rfid.write(0x02); //Send the command to read RFID tag, please refer to the manual for more detail.
}


void getID()
{
  for(int i=0; i<CARD_SIZE; i++){
    delay(10);
    readCard[i] = rfid.read();
  }
}

void printID()
{
  for(int i=0; i<CARD_SIZE; i++) {
    Serial.print(readCard[i],HEX);
    Serial.print(" ");
  }
  Serial.println();
}

// Check two arrays of bytes to see if they are exact matches
boolean checkTwo ( byte a[], byte b[] )
{
  if ( a[0] != NULL )             // Make sure there is something in the array first
    match = true;                 // Assume they match at first

  for ( int k = 0;  k < CARD_SIZE; k++ )  // Loop 5 times
  {
    /*
    Serial.print("[");
    Serial.print(k);
    Serial.print("] ReadCard [");
    Serial.print(a[k], HEX);
    Serial.print("] StoredCard [");
    Serial.print(b[k], HEX);
    Serial.print("] \n");
    */
    if ( a[k] != b[k] )           // IF a != b then set match = false, one fails, all fail
     match = false;
  }
  if ( match )                    // Check to see if if match is still true
  {
    //Serial.print("Strings Match! \n");
    return true;                  // Return true
  }
  else {
    //Serial.print("Strings do not match \n");
    return false;                 // Return false
  }
}

// Read an ID from EEPROM and save it to the storedCard[6] array
void readID( int number )  // Number = position in EEPROM to get the 5 Bytes from
{
   int start = (number * CARD_SIZE ) - CARD_SIZE + 1;  // Figure out starting position
   //Serial.print("Start: ");
   //Serial.print(start);
   //Serial.print("\n\n");

   for ( int i = 0; i < CARD_SIZE; i++ )  // Loop 5 times to get the 5 Bytes
   {
     storedCard[i] = EEPROM.read(start+i);  // Assign values read from EEPROM to array
     /*
     Serial.print("Read [");
     Serial.print(start+i);
     Serial.print("] [");
     Serial.print(storedCard[i], HEX);
     Serial.print("] \n");
     */
   }
}

// Looks in the EEPROM to try to match any of the EEPROM ID's with the passed ID
boolean findID( byte find[] )
{
  int count = EEPROM.read(0);             // Read the first Byte of EEPROM that
  //Serial.print("Count: ");                // stores the number of ID's in EEPROM
  //Serial.print(count);
  //Serial.print("\n");
  for ( int i = 1; i <= count; i++ )      // Loop once for each EEPROM entry
  {
    readID(i);                            // Read an ID from EEPROM, it is stored in storedCard[6]
    if( checkTwo( find, storedCard ) )    // Check to see if the storedCard read from EEPROM
    {                                     // is the same as the find[] ID card passed
      //Serial.print("We have a matched card!!! \n");
      return true;
      break;                              // Stop looking we found it
    }
    else                                  // If not, return false
    {
      //Serial.print("No Match here.... \n");
    }

  }
  return false;
}

// Write an array to the EEPROM in the next available slot
void writeID( byte a[] )
{
  if ( !findID( a ) )          // Before we write to the EEPROM, check to see if we have seen this card before!
  {
    int num = EEPROM.read(0);  // Get the numer of used spaces, position 0 stores the number of ID cards
    /*
    Serial.print("Num: ");
    Serial.print(num);
    Serial.print(" \n");
    */
    int start = ( num * CARD_SIZE ) + 1;   // Figure out where the next slot starts

    num++;                         // Increment the counter by one
    EEPROM.write( 0, num );        // Write the new count to the counter

    for ( int j = 0; j < CARD_SIZE; j++ )  // Loop 5 times
    {
      EEPROM.write( start+j, a[j] );  // Write the array values to EEPROM in the right position
      /*
      Serial.print("W[");
      Serial.print(start+j);
      Serial.print("] Value [");
      Serial.print(a[j], HEX);
      Serial.print("] \n");
      */
    }
    //successWrite();
  }
  else
  {
    //failedWrite();
  }
}

void openDoor(int setDelay)
{
  setDelay *=1000; // Sets delay in seconds
  digitalWrite(doorPin, HIGH); // Unlock door
  delay(setDelay);
  digitalWrite(doorPin,LOW); // Relock door
}