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27 June 2010 @ 03:41 pm
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:
Laying in supplies

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:
Charlie in acetone

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:
Charlie not faring too well in acetone

And after about 20 minutes, it looked like this:
Charlie pretty much destroyed

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

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:
New Charliecard

ETA: Thanks to spike, I now have a photo of the finished product:
RFID antenna under iPhone skin
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 ...
I'm feeling: accomplishedaccomplished
wolfkitnwolfkitn on June 28th, 2010 11:13 am (UTC)
Very, very nice. Does the shape of the antenna have to be maintained, or can it be bent, folded, etc? Also, if this works, it makes me wonder why they tell people that you can't punch a hole in the card to attach it to a keychain the way people used to do. Hmph.
... in a handbasketinahandbasket on June 28th, 2010 12:56 pm (UTC)
Because many people will punch through the antenna and ruin their card, and then they'll blame the MBTA for it. ;-)
It's easily doable if you know where the antenna is, and how to miss it.

aroraborealis: total win! nice work!
(Anonymous) on May 3rd, 2015 05:44 pm (UTC)
Punching a hole in my charlie card
Yeah, I did that very thing and ruined a card. Had I done more research, I would have known where I could and couldn't punch a hole. Oh well, live and learn.
ruthless compassion: martini handsaroraborealis on June 28th, 2010 01:52 pm (UTC)
The antenna can be in different shapes, but I think it needs to maintain a general loop shape, with all of the wires running in the same direction. I'm not sure, but there's some experimentation to be done here, obviously :)

As inahandbasket points out, the problem with hole punching is punching a hole in the antenna, which WOULD be a problem. Of course, knowing people like to punch holes in them, the T could have chosen to indicate a safe circle for doing so, or marked out where ISN'T safe, buuuut ... they didn't.
wolfkitnwolfkitn on July 2nd, 2010 03:12 am (UTC)
Yes, exactly... I can think of lots of daily T riders who'd love such an innovation on their charliecards as a small circle indicated on the silly thing... Like, to the extent that a suitably enterprising person could probably make a good money selling otherwise free, but hole-punched charliecards at park street.