July 16, 2012 AT 5:00 pm

How-To Embed a RFID Transit Card in your iPhone

Acetone dissolved

After seeing Dhani Sutanto mod his Oyster Card (London transit pass) into a ring, I got excited to try something similar with an CharlieCard (Boston’s RFID transit pass). You can dissolve the card in acetone and then remove the RFID antenna and chip inside. Check out our more detailed guide to this process over on our tutorial site. The video below contains the RFID-modding section of our iPhone replacement backs video:

Charliecard exposed

We found that when placed under one of our replacement iPhone backs, the tag didn’t read, so we fiddled with tape and paper until there was enough air space between the metallic bulk of the phone and the RFID antenna.


Charliecard taped

One post-it note and four layers of packing tape later, the tag scans just fine from within the back of the iPhone, even with 4G and wifi turned on.

Check out all the Circuit Playground Episodes! Our new kid’s show and subscribe!

Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground”Adafruit’s Apps!

Maker Business — Alibaba to invest $15b in tech, set up research labs around the world

Wearables — Special servo movement

Electronics — Trigger happy oscilloscope?

Biohacking — Biohacking: Visioneer – AI Glasses to Assist the Visually Impaired

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !


  1. I wonder if you could lay the antenna and module down on a GelaSkin and then apply that to the phone. Hopefully GelaSkins are going to RF transparent enough…

  2. I did a very similar thing with the keycard to my workplace a while ago.


    It read fine even through the metal of the stock iPhone back.

    However, though the back seemed to close fine on the pieces of the keycard, it caused the glass to bow slightly and the glass eventually broke when the phone suffered a light impact.

    I’m going to try again with a custom wound antenna and Kapton tape.


  3. Cool, I will try this with an Izmır kentkart and see how it works.

  4. Guillaume Marchand

    did you tried it on a “long range” reader?

    have a friend who’s on a project and have an issue with RFID tag applied behind and android phone. RFID reads fine on a close contact reader but prevent the tag from being read on a “gate” reader.

Sorry, the comment form is closed at this time.