I ride the T every work day, and most weekend days, and for all that I complain about how it could be better, I love being able to do most of my getting around on trains and buses. I don't, however, love having to keep track of my Charliecard, not specifically because of it but just because I have so many little bits and pieces of life I have to carry around every day: Charliecard, phone, wallet, keys, etc. Sometimes, I'd like to be able to leave the house with, say, JUST my phone and my keys. But I always want my Charliecard with me, because, hey, I never know when I'm going to want to hop on a bus and go somewhere interesting.

Wouldn't it be nice if my phone could be my T pass? Well, I realized, there's no reason it can't be. So I tried sticking the card under the skin I had on my phone, but it turns out the card is too big and bulky and is too stiff to conform to the shape of the phone. Rats. Except! I don't need the whole card, right? Just the RFID tag and antenna. So I set out to do that.

I needed a Charliecard, a non-plastic container, and some acetone:


ETA: It's a good idea to make a note of your Charliecard number before you destroy it. I just put it in as a memo in my phone. I've never needed the number of my card before, but it would annoy me to find that suddenly I did and couldn't retrieve it!

I used way more acetone than I really needed; just enough to cover it would be plenty:


Then, I waited. I don't know why I expected this step to take a couple of hours, but within a couple of minutes, the card looked like this:


And after about 20 minutes, it looked like this:


So I swished it around and plucked out the important part:


At this point, I wanted to be sure it would still work, so I tucked it into my book and brought it along on my commute the next day. I tapped it on the fare machine as if to load it up with money, and lo and behold! It worked! So I put my July pass on it, and brought it back home to stick it under the new skin for my phone:


ETA: Thanks to spike, I now have a photo of the finished product:

Because I just have a protective skin, rather than a case, you can tell there's something underneath, but not in a problematic way. At the point that you just have the RFID hardware, though, you could do any number of things with it, whether put it inside a skin or case for your phone, or apparently kids in London make bracelets out of it. For me, the cell phone/T pass combination is ideal. I'm so excited!

Feel free to share this around with anyone you think might find it useful for inspiring. Also, I have a lot of leftover acetone if anyone needs any ...