Convert your transit card to a wearable; step 1: dissolve in acetone
June 19, 2017 2:40 PM   Subscribe

Tired of carrying around your transit agency's contactless smart card? (for instance, in the San Francisco Bay Area, several transit agencies use Clipper Cards) Stephen Cognetta figured out how to convert it into a wearable by dissolving it in acetone, and has provided step-by step instructions and suggestions of different ways to wear the extracted chip.
posted by larrybob (76 comments total) 28 users marked this as a favorite
 
Hmm. Aren't there some uses where you still have to insert the card, not just wave it? I seem to recall that for my clipper card.
posted by tavella at 2:48 PM on June 19 [1 favorite]


I think to refill at the Caltrain station on 4th and King in SF you have to insert the card and leave it inserted why you add the cash. So could potentially be out of luck if you're in an emergency.
posted by Carillon at 2:54 PM on June 19


Yes: at the Temporary Transbay Terminal, at least, you insert your Clipper card to add value to it.
posted by sandettie light vessel automatic at 2:54 PM on June 19


And here I am keeping it in my wallet like a chump.
posted by tobascodagama at 2:56 PM on June 19 [5 favorites]


"...as a hardcore minimalist..."

OIC
posted by sandettie light vessel automatic at 2:58 PM on June 19 [16 favorites]


Don't try this with a card that really matters. It is a lot more fiddly than it looks. The wire is delicate.
posted by edd at 3:00 PM on June 19 [5 favorites]


Well, there's always the story about the guy in London who dressed up like a wizard and put his Oyster chip into the end of a magic wand.
posted by ckape at 3:06 PM on June 19 [68 favorites]


Thanks, ckape. Here's a 2008 blog post about dissolving Oyster cards. And a 2012 video of a witch with an Oyster wand.
posted by larrybob at 3:11 PM on June 19 [12 favorites]


Blogging about self-improvement, minimalist + stoic lifestyle
Ok... Clicks on the I’m a hardcore minimalist link and the first thing I read... "freeing up the money I would have spent on a new bed frame so that I can invest the money."

Do people feel imprisoned by their bed frames? Are they especially expensive? I bought my second hand for $30. You could always get a futon. Or why have a bed at all? Chew up some cardboard and make a nest. It works for squirrels and they are pretty minimalist, right?
posted by Ashwagandha at 3:12 PM on June 19 [67 favorites]


Good news: if you have a huge box of plastic foam packing peanuts, you can also dissolve them in a cup of acetone. Like, it dissolves to a tiny fraction of the peanut volume.

And then it's crazy flammable.
posted by GuyZero at 3:12 PM on June 19 [23 favorites]


Wait, so now I have to always be wearing a bracelet or carrying around some sort of pendant-y thing (don't drop it!) instead of just stuffing the card in my pocket (or better yet, in my wallet, which I am already carrying around )?

On preview: okay, opening fare gates with a tap of my magic wand would be pretty sick
posted by btfreek at 3:13 PM on June 19 [15 favorites]


I tried this with an Oyster card (London's contactless transit card) several years ago, unsuccessfully. I got the card apart but, weirdly, the aerial seemed to be a conductive track printed on a rubbery layer within the card, not an actual wire that I could extract. I only tried it that once -- at £3 a card, my curiosity was limited -- so I've no idea how prevalent that style of aerial is.

Very disappointing because, as ckape alludes to, I'd heard the story about the oyster card in the magic wand and really wanted to mimic it. Or possibly a watch strap.
posted by metaBugs at 3:13 PM on June 19 [1 favorite]


Chris Woebken did some similar work ten years ago with London’s Oyster cards, turning them into rings, wands, and other jewelry:
As an experiment I melted the Oystercard in Acetone and stripped it down to the essence., the bare coil wire with the RFID chip. I realized that the bus-driver does not care if i pay with a card or a wire, the actual transaction is just reduced to this beep - as long as it beeps it is okay.
posted by migurski at 3:19 PM on June 19 [3 favorites]


Some exchange students at MIT created a ring and got Boston MBTA to allow them to make it compatible with their system (I may have heard about these guys on MF). I purchased one and gave it to our fare collection engineering folks to play with, to see if we wanted to work with them, but so far, no official BART magic decoder ring.
posted by agatha_magatha at 3:26 PM on June 19 [20 favorites]


or better yet, in my wallet, which I am already carrying around

He already dissolved his wallet.
posted by Splunge at 3:29 PM on June 19 [49 favorites]


Years ago I did this to an MBTA card and stuck it inside the battery compartment of my Nexus One. It mostly worked.

I've tried doing this with an ORCA card and putting it inside the back of my iPhone's case; sadly I seem to recall it didn't work. I seem to recall suspecting the iPhone's own NFC antenna was causing problems.

These days I just have three ORCA cards: one in my wallet, and two firmly lodged in an outer pocket of a couple of my favorite bags, so I can just bounce the right corner of the bag off of the sensor box.

Really I just wish there was an app I could run on the phone that would let its NFC talk with the bus's NFC, but that ain't happening at the very least until IOS11, when Apple finally gives developers access to that. And then there's the question of whether or not their implementation is compatible with whatever's inside the bus' box. And of what happens if I'm out late and run out of phone battery.
posted by egypturnash at 3:37 PM on June 19 [3 favorites]


I was impressed when recently in London that you no longer need a special transit card at all. Just wave your contactless credit card near the reader and you're done. Or your iPhone, if you do Apple Pay. Done. Of course being an American my credit card isn't contactless; we only recently managed to upgrade to chips and we did that wrong, too. But I had an HSBC card with me and it worked great.

I assume contactless credit cards work on similar technology and the NFC is easily extracted.
posted by Nelson at 3:39 PM on June 19 [1 favorite]


Nelson: "
I assume contactless credit cards work on similar technology and the NFC is easily extracted.
"

I really hope that is the case. I'd love to be able to able to pay for gas with my gas cap.
posted by Mitheral at 3:44 PM on June 19 [2 favorites]


Good news: if you have a huge box of plastic foam packing peanuts, you can also dissolve them in a cup of acetone. Like, it dissolves to a tiny fraction of the peanut volume.

And then it's crazy flammable


This is basically how you make napalm.
posted by odinsdream at 3:45 PM on June 19 [20 favorites]


Is this some C Y B E R P U N K trend I've missed out on?
posted by hot_monster at 3:46 PM on June 19 [4 favorites]


The packing peanuts I've seen lately have been water-soluble. I don't know whether they'd dissolve in acetone but I suspect not.
posted by Joe in Australia at 3:48 PM on June 19


Makers gonna make
(whether it makes sense or not)
posted by Flashman at 3:49 PM on June 19 [6 favorites]


The packing peanuts I've seen lately have been water-soluble. I don't know whether they'd dissolve in acetone but I suspect not.

The acetone-soluble ones are largely polystyrene (bad). The water-soluble ones are probably starch-based (good). I'm a little torn, because a solution of polystyrene in acetone is toxic and flammable and gross, but gets rid of those blowy polystyrene bits that wind up in the environment.
posted by Existential Dread at 3:51 PM on June 19


For some reason I interpreted "wearable" as "embedded", and expected it to be along the lines of body hacking. Was relieved when it turned out not to be the case.
posted by olopua at 3:52 PM on June 19 [6 favorites]


Some exchange students at MIT created a ring and got Boston MBTA to allow them to make it compatible with their system (I may have heard about these guys on MF).

Just don't wear it to the airport.
posted by leotrotsky at 3:56 PM on June 19 [6 favorites]


I like the idea of a transit fare card (or credit card or whatever) that is more wearable, but it would also need to be part of a system that supported individuals having multiple card/non-cards that all attach to the same account. Because sometimes I might want to wear my transit ring and sometimes I might not want to and if I have a monthly pass on my ring, I shouldn't have to pay a separate fare on my card, or vice versa.

Perhaps something much smaller than a card but in a standard form factor that could be fit into a variety of accessories, so you could put it on a key ring or or in a bracelet or on a necklace or just keep it in your wallet.
posted by jacquilynne at 3:56 PM on June 19


An option if you break the antenna would be to print or 3D print your own.
posted by Existential Dread at 3:57 PM on June 19


I'm still envious of the fingernails.
posted by gingerbeer at 4:19 PM on June 19 [8 favorites]


Specifically, I would like someone to turn a Clipper card into press-on nails for me.
posted by gingerbeer at 4:20 PM on June 19 [5 favorites]


I knew a guy who took apart the chipped key for his Ford Focus and just superglued the chip right next to the key hole. Seemed to work ok.
posted by selfnoise at 4:23 PM on June 19 [2 favorites]


Or your iPhone, if you do Apple Pay.

Or, indeed, your watch, if you have one of those. It's very much like living in the future, until I remember that the real future looks like being an amdram production of The Road, but with fewer laughs.
posted by Grangousier at 4:25 PM on June 19 [7 favorites]


I got excited about trying this with my Opal card, but my partner just pointed out that it's prohibited by the T&Cs.

"Opal T&C 33.h not misuse, deface, alter, tamper with or deliberately damage or destroy the Opal Card;"

Why would they even care? That's annoying.
posted by web-goddess at 4:28 PM on June 19


MetaFilter: It works for squirrels and they are pretty minimalist, right?
posted by GenjiandProust at 4:29 PM on June 19 [5 favorites]


jacquilynne: "Perhaps something much smaller than a card but in a standard form factor that could be fit into a variety of accessories, so you could put it on a key ring or or in a bracelet or on a necklace or just keep it in your wallet."

Something like Italian charm bracelets perhaps.

web-goddess: "Why would they even care?"

Sounds like someone is trying to keep a security vulnerability secret.
posted by Mitheral at 4:33 PM on June 19 [2 favorites]


Belatedly discovered 2008 Previously about dissolving Oyster cards.
posted by larrybob at 4:34 PM on June 19


Via that Previously I learned about Hong Kong's Octopus card, and apparently there are a ton of official Octopus Ornaments ("Fashionable, trendy and fun to wear, they serve as more than fashion accessories. They function just like any Octopus") and licensed watches.
posted by larrybob at 4:39 PM on June 19 [3 favorites]


If I could get these coated in PTFE I’d totally have one implanted in my right hand. I already have a magnet in a finger and this would be infinitely more useful on a day to day basis.
posted by mikesch at 4:39 PM on June 19 [2 favorites]


Real stoics walk.
posted by Alvy Ampersand at 4:39 PM on June 19 [19 favorites]


Minneapolis has pay by phone! It's just an app that displays a special screen to the bus driver/train fare checker. The screen is animated (so you can't cheat using a simple screenshot) and it has a QR code (so they can validate it if they're suspicious, but they usually don't bother). Low tech but it seems to work.
posted by miyabo at 5:00 PM on June 19 [4 favorites]


In Toronto, you can dissolve a Presto card in acetone and it will still not work, just like when it was new.
posted by Kabanos at 5:39 PM on June 19 [42 favorites]


I knew a guy who took apart the chipped key for his Ford Focus and just superglued the chip right next to the key hole. Seemed to work ok.

God I wish someone gave enough of a shit to make car keys not be bloated horseshit. Mine has three damn buttons on it and a tiny chip, does literally 1/1000th of what my old-ass iPhone does, and is at least 50% thicker. These things are supposed to go in pockets.

2017, y'all.
posted by middleclasstool at 5:51 PM on June 19 [6 favorites]


I already have a magnet in a finger

Please, go on....
posted by rue72 at 6:06 PM on June 19


Thanks, egypturnash for answering if it might work with an ORCA card. Though, I think I have a spare, empty ORCA card I could screw around with.

I also remember the magic wand trick and loved it.

I'm wondering if getting a map of the internals of a card and mechanically modifying it right on the substrate would work better than dissolving the whole thing. This might be a trick for origami and paper cutting. Maybe get an X-ray or light shining through a card to carefully cut it back to a bare minimum, or sanding a card thinner with high grit count sand paper.

You might be able to carefully cut around, score and or shape a card in a way that it folds into a new shape around whatever object or embedded end use.
posted by loquacious at 6:38 PM on June 19


I already have a magnet in a finger

Surprisingly, I think I still want this. Didn't Cody from Cody's Lab get one?
posted by loquacious at 6:40 PM on June 19 [1 favorite]


It works for squirrels and they are pretty minimalist, right?

Squirrels are total hoarders!
posted by ssg at 7:03 PM on June 19 [6 favorites]


I already have a magnet in a finger

Please, go on....


See? It's already working.
posted by NoMich at 7:27 PM on June 19 [2 favorites]


Oyster card? Orca card? Octopus card? Geez, it's almost as if these subway systems *want* the ocean to drown their undergrounds.
posted by NoMich at 7:28 PM on June 19 [8 favorites]


Eh, I think the card is damn near the most generally convenient form already. Larger and it would be a nuisance, smaller and I'd keep losing it. The comment above about having a universal card for everything sure would be nice though; I have a military CAC, a Suica, a Passmo, a DC Metro (SmartTrip, I think it's called), and sometimes a hotel room key. Some don't like to be used in the presence of others, so the "just wave your wallet at it" thing doesn't work for me. I always have to take the individual card out.

Just standardize the protocol and let me charge it with multiple systems' accounts/secret info (for the hotel key) at once.
posted by ctmf at 7:34 PM on June 19 [4 favorites]


dang, and i thought i was clever putting my lanyard badge in my wallet
posted by indubitable at 7:57 PM on June 19 [1 favorite]


middleclasstool: "God I wish someone gave enough of a shit to make car keys not be bloated horseshit. Mine has three damn buttons on it and a tiny chip, does literally 1/1000th of what my old-ass iPhone does, and is at least 50% thicker. These things are supposed to go in pockets.

2017, y'all.
"

The car key also has to work at -40, +50, not be damaged by 80 degree temps, subjected to moisture and regular torque forces, without charging, for at least 10 years.
posted by Mitheral at 8:54 PM on June 19 [9 favorites]


The comment above about having a universal card for everything sure would be nice though;

Until you lose that one card, or it stops working.
posted by bongo_x at 9:39 PM on June 19


I got excited about trying this with my Opal card, but my partner just pointed out that it's prohibited by the T&Cs.

I'm going to do it anyway. What are they going to do to me?

I'll try it with my guest Opal card first, though, which currently has -$1 on it.
posted by lollusc at 10:31 PM on June 19 [1 favorite]


The comment above about having a universal card for everything sure would be nice though;

You can just use your bank card or your phone instead of the Oyster card, it charges the same.
posted by biffa at 1:04 AM on June 20 [1 favorite]


I keep my transit card in a wrist wallet and whenever I boop it on the boop thing to get on the bus or train people already think it's some kind of witchcraft.

I like gadgetry and convenience but you might want to be careful if there are a lot of witchfinders* in your particular metro area because if someone's cattle fall ill or the crops fail guess who they are gonna come looking for.



*you know those motherfuckers work for Google right
posted by louche mustachio at 3:53 AM on June 20 [4 favorites]


The car key also has to work at -40, +50, not be damaged by 80 degree temps, subjected to moisture and regular torque forces, without charging, for at least 10 years.

but my pockets...
posted by middleclasstool at 4:02 AM on June 20 [1 favorite]


Neat! Though while less fiddling at the fare gates is all well and good, I think I still prefer the ultimate no-fiddling solution based on paper tickets and five magic words printed on an overhead sign.
posted by wachhundfisch at 4:18 AM on June 20 [7 favorites]


My bank used to offer a mini debit card with a hole punched in it for putting on your keychain. It wouldn't work in any situation where you had to insert the card (like gas pumps or ATMs) but it was fine for swiping through your average retail card reader. It was a lifesaver for me on several occasions. I am famous for going to the grocery store, gathering up a full cart load of food and then realizing I've forgotten my wallet when I get up to the register. I can't get very far without my car keys, though, so I always had a back up. It went away with the advent of chip cards, though.
posted by Rock Steady at 4:36 AM on June 20


I'm waiting for Mikesch to tell us more about the implanted magnet...
posted by Capybara at 5:56 AM on June 20


I tried to do this with an expired bus card (since the RFID was still good for getting into my local hackspace).

Alas, after leaving it in acetone overnight, it was just...a card. I guess Nottingham City Transport makes their cards out of stronger stuff.
posted by Katemonkey at 7:04 AM on June 20


The card in the FPP was left in acetone for "3-4 days", so keep at it!
posted by btfreek at 7:47 AM on June 20 [2 favorites]


Yeah. Near the end you can see the level of acetone dropping due to evaporation. I hope he had his romm well ventilated.
posted by Splunge at 9:40 AM on June 20


That bit kind of bugged me - why didn't he just seal the jar? AFAIK there's no trouble with keeping acetone sealed as long as you don't heat it up at the same time (think bottles of nail polish remover). Less dangerous, less wasteful - I remember doing this to clean some 3D printer heads, though admittedly that was on the scale of hours, not days.
posted by btfreek at 10:03 AM on June 20 [1 favorite]


In the comments section on this page, the guy says:
I put some seran wrap on top so that it wouldn't cast a shadow when filming the timelapse
posted by NoMich at 10:16 AM on June 20 [1 favorite]


I just put my Minneapolis transit card in the outermost part of my wallet, under my license. Thin enough that I can just lean near the card reader and it picks it up.

Yes, I get on the train by putting my butt on the card reader. It's the right height. Don't judge me.

Also I own a bed frame. But I don't cheat on the number of my belongings by "borrowing" my roommate's pots and pans instead of owning my own like a grown-ass man. (Nuh-uh, I only have 115 things, that TV belongs to Joe, I am just using it in my room for now...)
posted by caution live frogs at 11:01 AM on June 20


OK: I have dissolved my bed in acetone, am unclear on what the next step is
posted by sandettie light vessel automatic at 1:37 PM on June 20 [4 favorites]


I think you're supposed to take it to the subway and do something with it.
posted by bongo_x at 2:36 PM on June 20


Rock Steady: "My bank used to offer a mini debit card with a hole punched in it for putting on your keychain. "

Esso in Canada offers a keychain device that works with Tap to Pay called Speedpass (which is linked to a credit card); but it only works at Esso and here the Esso stations are 2 cents a litre more expensive than most other places.
posted by Mitheral at 3:05 PM on June 20


Squirrels are total hoarders!

Squirrels don't store the food in their own homes though. They store their food in other people's yards. Hey there's a minimalist concept - have a lot of stuff but just store it other people's houses!
posted by Ashwagandha at 5:26 PM on June 20 [3 favorites]


As you know, I’m a hardcore minimalist. I was getting tired of carrying around so many cards in my wallet and wanted to experiment with transforming my cards to a different form factor.

I see a man, his arms covered with thin rubber bracelets, and his neck weighed down by tiny necklaces.

Yes, I get on the train by putting my butt on the card reader. It's the right height. Don't judge me.

Clipper card readers are not at butt-height. That is very important contextual information for all of this.
posted by Going To Maine at 6:57 PM on June 20 [1 favorite]


Man, I would just settle for my city having a contactless smart card at all. I'd let it take up my whole damn wallet.
posted by ferret branca at 7:04 PM on June 20 [2 favorites]


Squirrels don't store the food in their own homes though. They store their food in other people's yards.

Can a yard truly be considered to belong to someone who isn't storing their acorns in it?
posted by tobascodagama at 9:48 PM on June 20 [3 favorites]


Can a yard truly be considered to belong to someone who isn't storing their acorns in it?

I think that might be a zen koan.
posted by Ashwagandha at 9:59 PM on June 20


Mitheral: Esso in Canada offers a keychain device that works with Tap to Pay called Speedpass (which is linked to a credit card); but it only works at Esso and here the Esso stations are 2 cents a litre more expensive than most other places.

That actually reminded me that Exxon used to offer a similar thing here in the States. It seems like they have switched to a smartphone app, which is actually better than a keychain dongle for me. Thanks, Mitheral!
posted by Rock Steady at 6:25 AM on June 21 [1 favorite]


So I've now tried this with an opal card and can confirm it works, as long as you are careful about how you wind the wire. However I'm too scared of the men with the beepy checky thing to use this as my daily card. I don't know if I could convince them that it's really an opal card and not some sort of scam to defeat the machine.
posted by lollusc at 6:59 PM on June 23 [1 favorite]


I don't know if I could convince them that it's really an opal card and not some sort of scam to defeat the machine.

I would love to witness that explanation.
posted by bongo_x at 9:06 PM on June 23


"I'm a minimalist, you see..."
posted by The corpse in the library at 7:19 AM on June 24


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