Adafruit will not be shipping USPS orders Monday February 18, 2019 for the federal holiday, Presidents Day. Expedited USPS orders placed after 11am ET Friday February 15 will go out Tuesday February 19.

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.

Please vote for Limor Fried (Ladyada) for Red Hat’s Women in Open Source Award
Our Ladyada (Limor Fried) was nominated for Red Hat’s Women in Open Source Award! Please vote for her! Visit:

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Join 10,000+ makers on Adafruit’s Discord channels and be part of the community!

CircuitPython 2019!

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!

Follow Adafruit on Instagram for top secret new products, behinds the scenes and more

Maker Business — Apple manufacturing in the U.S.? Easier said than done.

Wearables — Hot glue undo

Electronics — Working with sensitive circuits?

Biohacking — Circadian Pi Desk Light

Python for Microcontrollers — Python is for the birds, deep dive, Raspberry Pi store, and more! #Python #Adafruit #CircuitPython @circuitpython @micropython @ThePSF @Adafruit

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


  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.