Don't cut your CharlieCard

[Ian David]

April 2nd, 2007

The CharlieCard, as some of you know, is the MBTA's reusable pass for subway / buss access. The only problem with it, aside from the fact that the system is constantly breaking, is that it's as big as a credit card so, if you're like me, it tends to not be in a readily accessible place as you approach the station. My keys are always accessible and I have little plastic frequent shopper type cards from six other companies there. "Wouldn't it be nice", I thought, "if i could find the chip in the card and then cut down the card without cutting the chip so that I could put it on my keyring." Well, I found the chip (in a strong light you can see it's imprint in the green bar under the guy with the blue hat) and when March had passed and April's pass was yet to be added to it (in case things went wrong), I proceeded to cut it down to a key-fob size. Alas, it didn't work.

The problem is that there is a thin wire antenna running around the edge of the card just 1/8th of an inch from the edge. If you're looking at the front of the card it's a hairs-breath above the top of "e", roughly 1/16th of an inch wide, and continues all the way around i think. Apparently without this antenna the signal just isn't strong enough to be read by the sensors. So, unless you feel like splicing your own antenna onto it, which might not be a bad idea, you can't cut it down.

What we really need is someone with access to anl x-ray machine to take a pic of their card and post it so that we can see exactly where that wire runs. Anyone know a doctor?

P.S. In case you're dubious as to the location of the chip, I have confirmed it by cutting my way into it once I had already confirmed that the card was borked.

More:
http://weblog.masukomi.org/2007/4/2/don-t-cut-your-charliecard