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Using the Parallax RFID Reader with an Arduino

This super-quick tutorial shows you how to set up the Parallax RFID Reader within the Arduino development platform.

  • By
  • Time Required: 10 to 20 minutes
  • Difficulty: Easy
Using the Parallax RFID Reader with an Arduino

If you’ve ever wanted the ability to use some form of hardware-based authentication in your projects then this is the board to do it with. The Parallax RFID (Radio Frequency Identification) reader is super easy to configure. It only takes four wires! It uses serial protocol to transfer information from RFID cards to the Arduino. This project is a quick introduction to using this RFID reader with the Arduino system.



Step #1:

Using the Parallax RFID Reader with an Arduino
  • This step is simple. Just gather up your needed components. You will need:
  • Four jumper wires
  • Parallax RFID reader
  • Arduino development board
  • Optional breadboard
  • That's it! Moving on....

Step #2:

Using the Parallax RFID Reader with an ArduinoUsing the Parallax RFID Reader with an ArduinoUsing the Parallax RFID Reader with an Arduino
  • Wire the RFID reader to the Arduino. Follow the pin mapping text below.
  • Arduino Rx = RFID SOUT
  • Arduino D2 = RFID Enable
  • Arduino GND = RFID GND
  • Arduino 5v = RFID VCC
  • D2 means digital pin number 2.

Step #3:

Using the Parallax RFID Reader with an Arduino
  • Toss some code onto the Arduino.
  • There are MANY different versions of Arduino code for this RFID reader. However, the best code I have seen to date was written by Benjamin Eckel. I have posted his code on my github account for archival purposes. You can get it here.
  • Now that the RFID reader is talking to your Arduino, you are ready to hack the code up and create a really cool project!
  • The sendCode function is what one would hack in order to use the RFID reader for something other than printing the tags to a terminal. To fully understand the code, you should read the datasheet in full. You can get it here.

Step #4:

Using the Parallax RFID Reader with an Arduino
  • That's all there is to it. This is basically a stub and I encourage you to add your own experiences with using an RFID reader with an Arduino.
  • Leave your questions and other thoughts using the Make: Projects notes feature.


Once you are able to connect to and read RFID tags, you are ready to integrate this into a larger project. Perhaps an RFID-enabled candy safe? Or an RFID garage door opener? There are many options. Good luck!

For Arduino news, features, tutorials, a buyer's guide, and more, visit the Make: Arduino page.

  • Eric

    This was great, but found a bug in the parallax reader where occasionally after re-enabling it will resend the last stored tag data. I fix this by flushing the serial buffer before reading after a re-enable…

    • What Arduino board did you work with? I’m trying to get this working on the Mega 2560 but to no avail. I set up the TX and RX pins for 14 and 15 (respectively) and the RFID reader seems to connect and shows the red LED. But when I wave my dongle over it, nothing. Can you help me?

  • ARay

    How do you flush the serial buffer? I’m having a similar problem. Soooo close to figuring this project out – wanna just fix this little problem.

    • Flush the serial? I haven’t even gotten the thing to read a single card! Have you gotten it to read something using the code provided here? I’m on an Arduino Mega 2560 so I have to switch around some pins and assignments and I feel like that’s screwing with things..

      • ARay

        I didn’t use the code on this page, but I’m having the same problem. Whenever I shut power off to the Parallax readers/arduino it’s like it “loses” the tags its stored.

  • I am getting a error:
    avrdude: stk500_recv(): programmer is not responding

    When I try to upload it to my board. The board works on simple sketches like the blinking light.

  • I got it to work with the code from arduino. However, I am new and do not know how to use the serial monitor.