/*
 * HID RFID Reader Wiegand Interface for Arduino Uno
 * Written by Daniel Smith, 2012.01.30
 * www.pagemac.com
 *
 * This program will decode the wiegand data from a HID RFID Reader (or, theoretically,
 * any other device that outputs weigand data).
 * The Wiegand interface has two data lines, DATA0 and DATA1.  These lines are normall held
 * high at 5V.  When a 0 is sent, DATA0 drops to 0V for a few us.  When a 1 is sent, DATA1 drops
 * to 0V for a few us.  There is usually a few ms between the pulses.
 *
 * Your reader should have at least 4 connections (some readers have more).  Connect the Red wire 
 * to 5V.  Connect the black to ground.  Connect the green wire (DATA0) to Digital Pin 2 (INT0).  
 * Connect the white wire (DATA1) to Digital Pin 3 (INT1).  That's it!
 *
 * Operation is simple - each of the data lines are connected to hardware interrupt lines.  When
 * one drops low, an interrupt routine is called and some bits are flipped.  After some time of
 * of not receiving any bits, the Arduino will decode the data.  I've only added the 26 bit and
 * 35 bit formats, but you can easily add more.

*/

#include <SD.h>
#include <stdlib.h>

#define MAX_BITS 100                 // max number of bits 
#define WEIGAND_WAIT_TIME  3000      // time to wait for another weigand pulse.  

unsigned char databits[MAX_BITS];    // stores all of the data bits
unsigned char bitCount;              // number of bits currently captured
unsigned char flagDone;              // goes low when data is currently being captured
unsigned int weigand_counter;        // countdown until we assume there are no more bits
unsigned int newCard = 0;

unsigned long facilityCode=0;        // decoded facility code
unsigned long cardCode=0;            // decoded card code

File cardFile;

// interrupt that happens when INTO goes low (0 bit)
void ISR_INT0()
{
  //Serial.print("0");
  bitCount++;
  flagDone = 0;
  weigand_counter = WEIGAND_WAIT_TIME;  
  
}

// interrupt that happens when INT1 goes low (1 bit)
void ISR_INT1()
{
  //Serial.print("1");
  databits[bitCount] = 1;
  bitCount++;
  flagDone = 0;
  weigand_counter = WEIGAND_WAIT_TIME;  
}

void setup()
{
  pinMode(1, OUTPUT); // RFID BEEPER
  pinMode(6, OUTPUT); // RFID GREEN LED
  pinMode(9, OUTPUT);  // DOOR LOCK
  pinMode(7, OUTPUT);  // blue LED
  pinMode(4, OUTPUT); // RFID RED LED
  pinMode(8, OUTPUT);  // yellow LED
  pinMode(2, INPUT);     // DATA0 (INT0)
  pinMode(3, INPUT);     // DATA1 (INT1)
  
  digitalWrite(1, HIGH); // RFID BEEPER
  digitalWrite(6, HIGH); // RFID GREEN LED
  
  digitalWrite(4, HIGH); // RFID RED LED
 
  
  //Serial.begin(9600);
  //Serial.println("RFID Readers");
  
  // binds the ISR functions to the falling edge of INTO and INT1
  attachInterrupt(0, ISR_INT0, FALLING);  
  attachInterrupt(1, ISR_INT1, FALLING);
  

  weigand_counter = WEIGAND_WAIT_TIME;
  
  //Serial.print("Initializing SD card...");
  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
  // Note that even if it's not used as the CS pin, the hardware SS pin 
  // (10 on most Arduino boards, 53 on the Mega) must be left as an output 
  // or the SD library functions will not work. 
   pinMode(10, OUTPUT);
 
  if (!SD.begin(10)) {
    //Serial.println("initialization failed!");
    digitalWrite(8,HIGH); 
    delay (5000);
    digitalWrite(8,LOW);
    return;
  }
  //Serial.println("initialization done.");
  digitalWrite(7,HIGH); 
    delay (5000);
    digitalWrite(7,LOW);
    
}

void loop()
{
  // This waits to make sure that there have been no more data pulses before processing data
  if (!flagDone) {
    if (--weigand_counter == 0)
      flagDone = 1;	
  }
  
  // if we have bits and we the weigand counter went out
  if (bitCount > 0 && flagDone) {
    unsigned char i;
    
    //Serial.print("Read ");
    //Serial.print(bitCount);
    //Serial.print(" bits. ");
    
    // we will decode the bits differently depending on how many bits we have
    // see www.pagemac.com/azure/data_formats.php for mor info
    if (bitCount == 35)
    {
      // 35 bit HID Corporate 1000 format
      // facility code = bits 2 to 14
      for (i=2; i<14; i++)
      {
         facilityCode <<=1;
         facilityCode |= databits[i];
      }
      
      // card code = bits 15 to 34
      for (i=14; i<34; i++)
      {
         cardCode <<=1;
         cardCode |= databits[i];
      }
      
      printBits();
      
      if(newCard == 1){ //add new card?
        addCard(facilityCode, cardCode);
        newCard = 0;
      }
      else {
        if(cardOK(facilityCode, cardCode)){
          //Serial.println("Access Granted");
          digitalWrite(7,HIGH);
          digitalWrite(8,HIGH);
          digitalWrite(6,LOW);
          digitalWrite(9,HIGH); // Unlock the door
          delay (6000);
          digitalWrite(9,LOW); // lock the door
          digitalWrite(7,LOW);
          digitalWrite(8,LOW);
          digitalWrite(6,HIGH);
        } else { //Serial.println("Access Denied")
        digitalWrite(4, LOW); // RFID RED LED
        digitalWrite(8, HIGH);  // yellow LED
        digitalWrite(1, LOW); // RFID BEEPER
        delay (50);
        digitalWrite(1, HIGH); // RFID BEEPER
        delay (50);
        digitalWrite(1, LOW); // RFID BEEPER
        delay (50);
        digitalWrite(1, HIGH); // RFID BEEPER
        delay (50);
        digitalWrite(1, LOW); // RFID BEEPER
        delay (50);
        digitalWrite(1, HIGH); // RFID BEEPER
        delay (50);
        digitalWrite(4, HIGH); // RFID RED LED
        digitalWrite(8, LOW);  // yellow LED
       }
      }
      
    }
    else if (bitCount == 26)
    {
      // standard 26 bit format
      // facility code = bits 2 to 9
      for (i=1; i<9; i++)
      {
         facilityCode <<=1;
         facilityCode |= databits[i];
      }
      
      // card code = bits 10 to 23
      for (i=9; i<25; i++)
      {
         cardCode <<=1;
         cardCode |= databits[i];
      }
      
      printBits();
      
      //Check if writing to, or checking card number file
      if(facilityCode == 100 && cardCode == 3181){
        digitalWrite(7, HIGH);  // blue LED
        digitalWrite(6, LOW); // RFID GREEN LED
        delay (100);
        digitalWrite(6, HIGH); // RFID GREEN LED
        delay (100);
        digitalWrite(6, LOW); // RFID GREEN LED
        delay (100);
        digitalWrite(6, HIGH); // RFID GREEN LED
        delay (100);
        digitalWrite(6, LOW); // RFID GREEN LED
        delay (100);
        digitalWrite(6, HIGH); // RFID GREEN LED
        digitalWrite(6, LOW); // RFID GREEN LED
        newCard = 1;
        //Serial.println("Add mode");
      }
      else if(newCard == 1){ //add new card?
        addCard(facilityCode, cardCode);
        newCard = 0;
        //Serial.println("Read mode");
      }
      else {
        if(cardOK(facilityCode, cardCode)){
          //Serial.println("Access Granted");
          digitalWrite(7,HIGH);
          digitalWrite(8,HIGH);
          digitalWrite(6,LOW);
          digitalWrite(9,HIGH); // Unlock the door
          delay (6000);
          digitalWrite(9,LOW); // lock the door
          digitalWrite(7,LOW);
          digitalWrite(8,LOW);
          digitalWrite(6,HIGH);
        } else { //Serial.println("Access Denied")
        digitalWrite(4, LOW); // RFID RED LED
        digitalWrite(8, HIGH);  // yellow LED
        digitalWrite(1, LOW); // RFID BEEPER
        delay (50);
        digitalWrite(1, HIGH); // RFID BEEPER
        delay (50);
        digitalWrite(1, LOW); // RFID BEEPER
        delay (50);
        digitalWrite(1, HIGH); // RFID BEEPER
        delay (50);
        digitalWrite(1, LOW); // RFID BEEPER
        delay (50);
        digitalWrite(1, HIGH); // RFID BEEPER
        delay (50);
        digitalWrite(4, HIGH); // RFID RED LED
        digitalWrite(8, LOW);  // yellow LED
       }
      }
    }
    else {
      // you can add other formats if you want!
     //Serial.println("Unable to decode."); 
    }

     // cleanup and get ready for the next card
     bitCount = 0;
     facilityCode = 0;
     cardCode = 0;
     for (i=0; i<MAX_BITS; i++) 
     {
       databits[i] = 0;
     }
  }
}

void printBits()
{
      // I really hope you can figure out what this function does
      //Serial.print("FC = ");
      //Serial.print(facilityCode);
      //Serial.print(", CC = ");
      //Serial.println(cardCode); 
}

void addCard(unsigned long fc, unsigned long cc){
  cardFile = SD.open("cards.txt", FILE_WRITE);
  if(cardFile){
    //Serial.print("Added card: ");
    //Serial.print(fc);
    //Serial.print("-");
    //Serial.println(cc);
    cardFile.print(fc);
    cardFile.print("-");
    cardFile.println(cc);
    cardFile.close();
    digitalWrite(6, HIGH); // RFID GREEN LED
    digitalWrite(7, LOW);  // blue LED
  }else{ //Serial.println("Error opening file")
; }
}

boolean cardOK(unsigned long fc, unsigned long cc){
  
  cardFile = SD.open("cards.txt");
  if(cardFile){
    //Serial.print("Checking card...");
    char curNum [16];
    int index = 0;
    unsigned long fcode;
    unsigned long ccode;
    while(cardFile.available()){
      if(cardFile.peek() == '-'){
        curNum[index] = '\0';
        fcode = strtoul(curNum, NULL, 10);
        index = 0;
        cardFile.read();
      }
      else if(cardFile.peek() == '\n'){
        curNum[index] = '\0';
        ccode = strtoul(curNum, NULL, 10);
        index = 0;
        cardFile.read();
		
		if(fcode == fc && ccode == cc){
			return true;
		}
      }
      else{
        curNum[index] = (char)cardFile.read();
        index++;
      }
    }
    
    cardFile.close();
    
    return false;
  } else { //Serial.println("Error opening file"); 
return false; }
}