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Coin Card Teardown

171 points| monkeypod | 10 years ago |bitsofcents.com

116 comments

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[+] joshstrange|10 years ago|reply
I had the beta and a final Coin and neither one were reliable enough to to trust. You HAVE to carry backup cards which more or less defeats the purpose. Then there is the slightly embarrassing, extremely annoying "Your card didn't work/Do you have another card this one isn't swiping". I've stopped carrying my coin altogether because if you have the cards you might as well use the real ones (I tried for 7+ months to use coin first).
[+] goeric|10 years ago|reply
Agreed. The coin absolutely failed me. It didn't work far too often for me and I always had to carry backup cards (my debit card because BofA's ATM can't read it, and my credit card because I still want my rewards on purchases when my Coin fails). Needing to carry 3 cards completely defeated the purpose of the Coin, and I ended up ditching the Coin just to have one less card in my wallet. The irony.
[+] markbnj|10 years ago|reply
They probably didn't have the ability to test it on nearly enough readers, given that there are literally thousands. They may also be running into some timing issues based on how people swipe. Those are things you sometimes just can't work out barring wide scale testing and adoption.
[+] jkestner|10 years ago|reply
The concept is inherently flawed. Never mind changes in the payment infrastructure—the cool factor has apparently outweighed engineering challenges.

This is a (probably less severe) variation of the problem that iCache [1] had. The dynamic magnetic stripe tech was immature then, but mostly, it's just really difficult to put a computer in a thin (read: flexible) object that people are used to abusing. Then consider the need for near-perfect reliability next to the promoted benefit of not carrying other cards, and you're screwed.

1. https://www.kickstarter.com/projects/1404403369/geode-from-i...

[+] martingordon|10 years ago|reply
Even worse, I've had servers flat out refuse to accept it. I couldn't even imagine opening a tab at a bar with it either: It looks too fake to be taken as collateral, and I don't know if the magnetic strip still works if the card is locked, meaning I would have to have another round-trip interaction with the bartender.
[+] tracker1|10 years ago|reply
I've actually been meaning to try google wallet (pretty much everywhere visa/mc tap to pay and apple pay are available too) for some time, and just never think to do it... when I saw the coin card, I thought it was an interesting idea, but to be honest, I think having something along with your phone is probably more useful, since anyone with a coin card is likely to also have their phone.
[+] jdhawk|10 years ago|reply
Ditto - great idea - just never works reliably
[+] ceequof|10 years ago|reply

  The specs aren’t listed on the FDK site but the safety 
  data sheet shows it is a 3V battery although amperage is 
  unclear.
All lithium-ion batteries have a nominal voltage of 3.7V, like how all alkaline batteries have a nominal voltage of 1.5V. It's just how the chemistry works.

(Actual voltage can vary quite a bit, depending on where you are in the discharge curve: http://i.stack.imgur.com/UkodS.gif)

And to be somewhat needlessly pedantic: you want "amp-hours" there, not "amperage". Amp-hours is the unit of capacity, amps is how much current is being drawn at that very moment. In the automotive metaphor, amp-hours (or watt-hours) is how big the gas tank is, while amperage is engine horsepower.

[+] Dylan16807|10 years ago|reply
Lithium is not lithium ion.

Single-use lithium batteries are made in a variety of voltages. This chemistry is in fact three volts.

[+] stephengillie|10 years ago|reply
What Coin has managed to do in such a thin package is really impressive. It’s a shame they weren’t able to do it more reliably.

It's a really cool idea. I actually wonder what the technological hurdle was that held them back - mechanical (reliably magnetizing the coils, easy-to-break components due to narrow size), software (programming issues), or QA (reliable SoCs, reliable builds, reliable solders)?

[+] pjc50|10 years ago|reply
I suspect flexing the PCB caused the usual problems of hairline cracks in solder joints, resulting in intermittent faults.
[+] jaboutboul|10 years ago|reply
It would have been nice if they shared any of that info. Maybe more of us would be more sympathetic.
[+] ngoel36|10 years ago|reply
Very often, the merchant would just assume I was using an Amex e.g. Amex Black....even though the display read VISA. This, of course, caused a decline...not worth the trouble to argue.
[+] ngoel36|10 years ago|reply
I was so damn excited to use my Coin - the idea was brilliant. I tried to so hard to use it, but with a 30%+ failure rate, it became completely useless. Simply not worth the embarrassing "Sir, your card didn't work" or "Is this real?". And if I have to carry backups anyways, what's the point?
[+] BrentOzar|10 years ago|reply
I like it because it got me down from several cards (debit, credit card A, credit card B, business card, business debit card) to two (debit card, Coin). The debit card is my backup to Coin.
[+] yrral|10 years ago|reply
Fcc photos of the coin pcb here [1]

I think that the coils that drive the magstripe are only activated when the buttons to the left or right of the stripes are depressed (e.g. by the process of swiping).

Also, I believe coin only transmits track 2 [2]. Why it looks like there's 2 coils is curious to me as well.

[1] https://fccid.io/document.php?id=2397353

[2] https://support.onlycoin.com/hc/en-us/articles/204263414-Coi...

Some merchants require your full name (also known as Track 1 card data) as a part of the transaction process. Coin does not transmit Track 1 data and may be rejected at the point of payment.

[+] joezydeco|10 years ago|reply
It seems like a logical thing to do, especially when you're trying to a) save power and b) time the speed of the coil's "stripes" to make the reader think it's seeing a physical card. It's probably also the source of a lot of rejected swipes.

Conductive rubber pads and/or membrane switches are always a bad thing. Necessary for this design, but they'll always fail you in the end.

[+] mildweed|10 years ago|reply
I certainly have been rejected because of the lack of Track 1 data. One merchant told me as much.
[+] treycopeland|10 years ago|reply
I received my Coin about 2 months ago. I was excited to test it out after preordering almost 2 years in advance. The concept of having all my cards on one central card was a great idea. But having it not work at some locations was rather embarrassing and frustrating. I have decided the Coin was a fail and I will not carry it anymore. But, Coin, keep innovating. You tried.
[+] lvs|10 years ago|reply
It sounds like just another startup hardware offering with a spotty launch. But I've always been confused about the perceived "embarrassment" of a card not working at the point of a transaction. This seems to be a common marketing trope in payments, but I don't know what it comes from. It's a piece of technology, and tech often doesn't work quite right. Sometimes my phone restarts itself. What's the big deal?
[+] scoot|10 years ago|reply
If the mag-stripe emulation is just a simple electromagnet, I'm curious how they detected the position of the read-head in order to modulate the magnet correctly to emulate the data that would otherwise be read at that point of a traditional mag-stripe. Or is it more sophisticated still?
[+] mmosta|10 years ago|reply
Pretty cool.

I'm interested in knowing which component failed? did the second card fail in the same way? or was that remedied in the revision?

Did the display and button still work?

Hopefully the issue was with the coil, flex PCBs and displays are more or less a solved problem, batteries not so much.

With the Nordic 51822 they're lined up well to roll out NFC after the mandated phase out of mag-strip in the US (p.s how are they still a thing?).

It'll be interesting to see if they'll survive if a chip-and-pin foothold overshadows NFC.

[+] nadams|10 years ago|reply
Was I the only one who canceled their pre-order after they asked for your social security number?
[+] Globz|10 years ago|reply
This is the first time I am reading about this product but why mag stripe over smart cards? isn't it less secure and deprecated technology? it seems very useful but relying on mag stripe isn't the best move, no? Perhaps they couldn't "switch cards" while using smart cards so mag stripe was the only solution?
[+] stephengillie|10 years ago|reply
In the USA, magnetic swipe readers are EVERYwhere. And the collection of credit and debit networks connect every reader with almost every bank. It "just works" everywhere, and it's "impossible" for a retailer to be unable to connect to your bank.

-Chip-and-pin? The card reader probably can't read it.

-Apple/Google wallet and similar services? The card reader probably doesn't have an antenna for it. (Especially small retailers who can't afford the special card reader)

-NFC Visa/Mastercard? The card reader probably doesn't have an antenna for it.

-Paypal? Most retailers aren't set up for it. That's why Paypal issues magnetic cards in the USA.

-Paper checks? Most retailers don't want to lose money on the possibility of fraud. And most card readers can't auto-ACH a check.

[+] azdle|10 years ago|reply
The security that a smart card provides would actually prevent a product like this from working because one of the primary purposes of the chip system in CCs is to prevent cloning, but this relies on simply being able to enter your CC number into it.

I can't remember what it was called, but I remember reading about something that does use a chip card and allows you to switch payment providers using a phone app, but they were actually acting as a payment processor and had agreements with the card providers that they support to redirect charges to whoever you had selected at the time.

[+] Nursie|10 years ago|reply
It's not quite deprecated in the USA, yet. Just nearly everywhere else...
[+] jackmaney|10 years ago|reply
> isn't it less secure and deprecated technology?

Uhhhh...no? I've lived in the US my entire life, and while I've seen pin and chip readers, I've never had a pin and chip card, never known anyone who has ever had one, and never seen one used. Ever.

[+] upofadown|10 years ago|reply
>I was surprised by the number of test pads exposed on the Coin - all those small metallic squares are programing points / test points. This suggests to me that Coin is still going though some debugging since it’s rare to see so many pads still exposed on a shipping product.

Perhaps their tester just couldn't probe the smaller pads/components. In general, any shipping product these days is going to have a significant number of test points, it is just that they are often not explicit.

[+] tdicola|10 years ago|reply
> It doesn’t look like there are many other products using the 51822

Actually the nRF51822 is starting to pop up in a lot of products, especially those that use BLE. The BBC Micro Bit will be built around it: https://en.wikipedia.org/wiki/Micro_Bit

[+] mik3y|10 years ago|reply
How's the toolchain support / dev environment for the Nordic parts these days? I remember the "other" popular chips (TI CC2540 and friends) had a gross and expensive requirement on "IAR Workbench".
[+] myth_buster|10 years ago|reply
I'm curious to know whether given proliferation of the NFC alternatives available now like Apple/Google Pay is there a problem that Coin Card addresses which the former don't. Is paying in the restaurants one of those use case or will we see table side point-of-payments in near future which would make it obsolete.
[+] fluidcruft|10 years ago|reply
For what it's worth, all of my banks have already replaced my credit cards with chip-and-pin capable ones in preparation for October's rebalancing of fraud liability between merchants and banks. I can't imagine merchants will be too keen to accept these Coin cards.
[+] ianburrell|10 years ago|reply
In Canada, where they have switched to chip-and-pin cards, the servers bring a terminal to table. Customer puts in card, enters PIN, and enters tip amount. For swipe cards or chip-and-signature, it prints out a receipt to be signed.

Card would still be useful for terminals that don't support NFC payment. Or for larger payments than are allowed with NFC. Or for people who prefer to use cards instead of phone/watch.

It should be possible to use the tokenization system of Apply Pay to have switchable card with chip-only card.

[+] jtchang|10 years ago|reply
I actually have the Nordic NRF51822 / NRF51 development board and it is super fun to play with. I come from a web dev background so getting into hardware is rough.

The toolchain for building firmware is crazy. It's kind of like in webdev we dynamically generate css through sass and then put it through all these different stages (minification/etc). Except this is all old school Makefiles. Made me cringe a bit.

[+] deegles|10 years ago|reply
Does cloning your card to a Coin make you liable for fraudulent transactions? I assume it would be against the ToS for most cards to allow cloning.
[+] concerned_user|10 years ago|reply
That is what signature is for, isn't it? If bank can't prove it is your signature then it is a fraudulent transaction. Technically cashier/clerk should not accept the transaction if signature doesn't match but I've rarely seen them check it.
[+] dimino|10 years ago|reply
My Google Wallet card does the same thing this does.
[+] jackmaney|10 years ago|reply
I'm amazed that this idea actually caught on in the first place. "Wait, you mean I can put every single source of (non-cash) money in a single card, for a single point of failure? And if it breaks, I'm effectively penniless? WHERE THE FUCK DO I SIGN UP?!"
[+] concerned_user|10 years ago|reply
Also imagine it gets stolen, good luck remembering all the cards you had in there and banks you need to call. Payment gateway route, like paypal, gives same convenience and less headaches.
[+] dougb|10 years ago|reply
Coin is an interesting idea, but I figured https://www.dynamicsinc.com/ would sue the pants off of them for patent infringement once they went to market. Dynamics CEO is a former patent attorney.

dynamics seemed to have all the pieces in place to do the same thing.