Tonight was tapedeck disassembly night:
I’m trying to decode some metro cards for a DCist post in the vein of the the one where I pulled apart a SmarTrip card. But decoding magstripe data is a little harder than splashing around some acetone and plagiarizing wikipedia’s RFID article.
I started off trying to use this project and this reader. And it works great for most of the cards in my wallet — but not for metro cards. Strangely, this problem even occurs in raw mode, where the reader simply spits out ones and zeros. The blocks of digits occur in roughly the same places, but the sizes of these blocks aren’t consistent.
I’ve done some googling. From what I can tell, it looks like most financial institutions use a standard encoding scheme, complete with checksums and well-known formats. The stripesnoop reader and software expect this scheme, but DC metro cards don’t abide by it. In fact, they may not even be digital: apparently some older card systems are acoustic, using various overlapping frequencies to encode data (the same way that telephone touchtones do).
Anyway, I’m hopeful that this software will be up to the task of analyzing it. It’s a little more bare-bones: you hook a magnetic read head up to your sound card, record the sound of the magstripe and the software analyzes the resulting wav file. This is why I made that request for breakable tape decks — big thanks to Ray for providing a suitable victim (and to Matt and Jeff for similar offers).
At the very least I’ve managed to get a motor out of it and a useful-looking transformer that will probably prove to be even more dangerous than I suspect. But I’d say that odds of successfully decoding a card are low. If I can just produce some weird-sounding mp3s I’ll call this project a resounding success.
I’m glad you could salvage that junker for some potentially useful purpose. It was becoming the black sheep of the breakroom.
Whoops, completely forgot to give you the walkman after I grabbed it from my old room. Still need it?
Metro card noise could totally be the next big thing in the music world, methinks. A distortion pedal for the future.
Methinks the beer is the most important tool on the workbench there – what is that, a Sammy?
A smuttynose pumpkin ale, actually. Last pumpkin ale of the season, I suspect. Very sad — I don’t generally like octoberfest or winter brews very much (although some of the latter are pretty good).
And thanks for the offer Matt, but I think I should be fine w/ this. The second one was really about the recording head, which is probably way more ambitious a phase of this project than I’ll ever actually get to.
Pumpkin ale! Bite your tongueâthe last!
I do like Anchor Steam’s winter ale (Celebration, I think it’s called?), but otherwise I agree: It’s a long wait for the spring beers.
I don’t know, Kriston. On Tuesday night at Whole Foods I couldn’t find any pumpkins for sale except the decorative ones on the salad bar (which I helped myself to). Halloween has passed — it’s time for the pumpkins to sail into the west, and diminish.
it’s time for the pumpkins to sail into the west, and diminish.
I don’t know what’s worse, that you made that reference, or I got it.
I’m not a big fan of flavored beers, of either the winter/fall or kreik (sp?) variety, but I once had a (bottled) apricot beer that was really tasty.
“If I can just produce some weird-sounding mp3s I’ll call this project a resounding success.”
I despise flavored beers, but my company will pay cash money for these mp3s.
I have been looking for your blog since you posted on DCist. Sweet. Seriously sweet. To the feedreader!
(by the way, I’ve said it before and I’ll say it again: Manifest Destiny would be the best superhero. Especially if he had a sidekick called Social Darwin.)
Interesting blog, I myself have been interested for a while in card data and the like, but have not had the equipment up until recently. I am learning the process slowly but still do not fully understand all that is meant by the data tracks etc. Although I cannot yet encode smart cards I have today encoded my first few mags and played with a reader and some data. All my equipment has been sourced from kestronics and I’m hoping to continue to learn from them and others.
Although I have ordered cardfive software, for the timebeing I am using notepad and a reader, however It does not really allow me to know which track has been read and where to put the data for the new cards.