Sometimes I find myself carrying around a big wallet when all I need is a train card. Grab a little nail polish remover, though, and it looks like you can transplant the RFID chip from your clipper card to your cell phone:
(images via The Barrieluv Blog)
Things to take note of:
- Only soak the card in acetone for an hour or two- too long and it'll get too goopy to peel.
- Keep the antenna intact and roughly loop-shaped: the shape it how it gets enough power from the turnstile readers to authenticate.
- Verify it works a few times before making it your main transport card- good luck explaining to the fare cops that your Proof of Payment is in your phone if their readers don't work on it.
I'll let you know if I get it working. I believe it should work with most/all removable-back android phones, plus the iPhone 4/4S.