125Khz RFID Module - Wiegand

RDM 125KHz card mini-module is designed for reading code from 125KHz/ 134.2KHz card compatible read-only tags and read/write card . It can be applied in office/home security, personal identification, access control, anti-forgery, interactive toy and production control systems etc.

1.Pin Definition(Wiegand)

   P1:
        PIN1      DATA0
        PIN2      DATA1
        PIN3
        PIN4      GND
        PIN5      +5V(DC)
   P2:
        PIN1      ANT1
        PIN2      ANT2
   P3:
        PIN1      LED
        PIN2      +5V(DC)
        PIN3      GND

2.Specification and Parameter

FEATURES :

    * Support external antenna
    * Maximum effective distance up to 150mm
    * Less than 100ms decoding time
    * Wiegand interface
    * Support EM4100 compatible read only or read/write tags
    * Built-in external bi-color LED and buzzer driver
    * Small outline design

Including: External Antenna *1

Download :  #Datasheet#

Sample code for Arduino :

//******************************
#ifndef RFID
#define RFID
//==============================
#define DATA0 0x01 //Data pin 0 from RFID module
#define DATA1 0x02 //Data pin 1 from RFID module
#define D_PORT PORTB
#define D_DIR  DDRB
#define D_IN   PINB
//==============================
#endif
//******************************


void setup()
{
  Serial.begin(115200);
  D_DIR&=~(DATA0+DATA1);
}
void loop()
{
  unsigned char recieve_count=0;
  unsigned char card_num[4]={
    0,0,0,0  };
  for(;;)
  {
    unsigned char data0=0,data1=0;
    if(D_IN&DATA0)  //DATA0 incoming signal
    {
      data0=1;
    }
    if(D_IN&DATA1)  //DATA1 incoming signal
    {
      data1=1;
    }
    //--------------------------------------------    
    if(data0!=data1)  // card detected
    {
      recieve_count++;
      if(recieve_count==1) //drop even bit
      {
      }
      else if(recieve_count<10)// card data group 1
      {
        if(!data1)
        {
          card_num[0]|=(1<<(9-recieve_count));
        }
      }
      else if(recieve_count<18)// card data group 2
      {
        if(!data1)
        {
          card_num[1]|=(1<<(17-recieve_count));
        }
      }
      if(!data1) // card data group 3
      {		
        card_num[2]|=(1<<(25-recieve_count));
      }
      delayMicroseconds(80);  //Data impulse width delay 80us
    }
    else    // no card incoming or finish reading card
    {
      unsigned char i=0;
      if(recieve_count>= 25)  //output card number
      {
        recieve_count = 0; //reset flag
        for(i=0;i<4;i++)
        {			
          Serial.print(card_num[i],DEC);
          card_num[i]=0; //reset card_number array
        }
        Serial.println();// output debug value
      }
      //----------------------------------------------------      
    }
  }
}

Note: Module will notify whenever 125khz tag approaches, tag serial number will be send via IO pin and save UART port for MCU. Either interupt or polling mode is OK to read the ID, Arduino library pending.

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