Arduino RFID tag reader prototype

 Put together the basic Arduino RFID reader in about an hour!  It was way easier than I expected and worked the first time!  


<Note: See the final version in this post>
http://siliconfishtech.blogspot.com/2010/10/arduino-rfid-tag-reader-cleaned-up.html

Here is the prototype breadboard version I just whipped up:

The RFID module reads out serial ASCII data, and all you have to do is connect that output to a pin on the Arduino.  The serial library called in the code (the link is in the code) lets you put a serial input on any pin.

Thats all there is to it.  

You can read your tags, and put if statements in the loop to activate a pin on the arduino to make a lock, or whatever you want to happen when a card is read.   

• Used the RFID Reader ID-20 from Sparkfun:

            http://www.sparkfun.com/commerce/product_info.php?products_id=8628
           The datasheet is here:
           http://www.sparkfun.com/datasheets/Sensors/ID-12-Datasheet.pdf
           The ID-12 is functionally identical, with a smaller range and uses less power.  Pick that one for a battery operated project.

• This little breakout board for the RFID module is worth the $0.95 to make the pins plug into the breadboard.

           http://www.sparkfun.com/commerce/product_info.php?products_id=8423

• I got a couple of these tags for $1.95 each.  RFID Tag - 125kHz.  Even if you have your own tags, i'd get one to be sure the reader is working when you build it.

          http://www.sparkfun.com/commerce/product_info.php?products_id=8310

• Of course you need an Arduino Duemilanove from http://www.sparkfun.com/commerce/product_info.php?products_id=666 for $25, 
• A solderless breadboard and some wire and you are good to go!

It took some staring at the cryptic documentation and the web site below to figure out the circuit, so I drew it up since the drawings elsewhere were awful and had errors.

http://hcgilje.wordpress.com/resources/rfid_id12_tagreader/

The sketch code follows the break...


//nice, flexible serial library
//http://arduiniana.org/libraries/newsoftserial/
#include <NewSoftSerial.h>

//format (input, output)
//only the input is used in this example, output is unused
NewSoftSerial mySerial(8, 10);

int cardPresent = 9;
int led_pin = 13;

void setup()
{
  Serial.begin(57600);
  Serial.println("RFID Reader Active");
  pinMode(cardPresent, INPUT);
  pinMode(led_pin, OUTPUT);

  // set the data rate for the NewSoftSerial port
  mySerial.begin(2400);
}

void loop()                     // run over and over again
{

  if (digitalRead(cardPresent)==HIGH) {
    digitalWrite(led_pin, HIGH);
  } else {
    digitalWrite(led_pin, LOW);
  }
  if (mySerial.available()) {
      Serial.print((char)mySerial.read(),HEX);
  }
}