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Muxcard, a dyi credit card size computer

I went to the page expecting to rant about how it's not actually credit card size because of the thickness and was for once pleasantly surprised! Kudos to the author! It looks great!

3 hours agomabster

This post - the title made me remember ... ( as a credit card is about the same size as a business card )

A Linux Business Card CD is a miniature, credit-card-sized optical disc containing a stripped-down, bootable Linux operating system. They hold around 50MB to 100MB of data and were highly popular in the early-to-mid 2000s

More info at https://en.wikipedia.org/wiki/Bootable_business_card

8 hours agoasdefghyk

These things were cool! I believe I had some drivers installed via some of them, and a Kubuntu livecd.

3 hours agodevmor

this is really cool. I didn't know we had these

6 hours agommmehulll

Very cool! Love it...

But...

The battery is likely to be squeezed quite a bit after this is put in my wallet, and in my pocket.

Lithium batteries do not like to be squeezed. They tend to signal their distress with some type of heat, usually accompanied with a small fire and probable smoke as well.

A distressed battery is very insistent upon everyone to see it's state of mind...

an hour agorealo

This is discussed in the post.

an hour agoskavi

> A fully working computer that is literally the size of a credit card.

Nit: A (chip) credit card is already a fully working computer :)

4 hours agolxgr

Only if it is inside a specially designed radio field and with no independent IO. Feels like a battery and IO justify the 'fully working' differentiation.

3 hours agoZiiS

Interesting philosophical question: Is a tower PC that's not plugged into anything (neither power nor a keyboard or monitor) a computer? Does computation happen if nobody can perceive it? And is a computer a computer even between two CPU cycles?

> no independent IO

I would challenge that! How is a smartcard different from a server in a qualitative sense? Both get all their I/O over the network.

Some cards even have a display, fingerprint reader, or can blink an LED (the latter unfortunately only indiscriminately when powered up, not in response to any computation, I'm afraid).

2 hours agolxgr

Is a bare SoC a computer? You can poke the pins to provide power and I/O.

The interesting thing about this project is that this computer can function independently within a credit card sized space.

an hour agoRohansi

I've never heard a definition of a computer to include its power source.

IO is of course required.

3 hours agoIAmBroom

Developer here :)

Just saw this and love how I got the 100th or so "Does it run DOOM?". Even now officially an issue on GitHub. Does that mean I now have to deliver?

5 hours agokrauseler

How optimal is the PCB density? Do you think there is significant room for improvement to have a smaller PCB and larger screen and/or battery?

41 minutes agoabdullahkhalids

> Does that mean I now have to deliver? Well, if you'd like to, you're free to do so! If not, somebody else could do it. You're not your audience's slave

I know it was intended as a joke but still..

5 hours agoMuhammad523

So... it's not DOOM-complete?

Teenage Alan T. would be so disappointed... :D

3 hours agoIAmBroom

Prologium is depositing thin film solid state batteries onto flexible ceramic insulators. They have some demos of single cells that appear to be thinner than 1mm continuing to operate after bending in half.

https://prologium.com/tech/core-technology/

an hour agodeckar01

Hidden in here is the coolest part, that the author made flex PCBs at home

4 hours agoz3ugma

Just in time for DEFCON. We built many of these types of badges

4 hours agofiresteelrain

Coincidentally, the xteink x4 has the same CPU, an e-paper screen and is close to credit card sized.

5 hours agoWithinReason

I would love if the screen could take up more space, even at the expense of a little extra thickness.

7 hours agorbanffy

I think that there could be a wider screen if such formats are available. Once we have betavoltaic batteries, the entire card can be screen.

7 hours agojansan

I'm not sure beta voltaics will ever reach LiPo densities. All materials I know would be unwise to place in your wallet, or anywhere near your body.

If we are OK with a battery and a beta voltaic source, a tritium one is reasonably safe and can trickle charge the battery when the device is in deep low power mode. The battery can still be charged by the induction coil.

6 hours agorbanffy

dyi = Do Yourself It?

an hour agoacrophiliac

love this. would be cool if we can see and perform all kinds of banking txns on this. Think ledger but all in one card. Super cool. Even cooler would be card to card money transfer without use of swipe machines

6 hours agommmehulll

If "ledger on card" interests you, then you might enjoy Japan's FeliCa cards. They store balance locally on the card so you can pay very quickly, no network required.

6 hours agoresonious

Do these cards solve the electronic cash problem (in a completely different way than cryptocurrencies)? What I mean is that

- Are the card readers special/trusted issued by bank/govt in some way? Or you can transfer money from one card to another yourself fully offline?

- Is there any requirements that the transfers have to be eventually communicated to the bank by one of the parties to be fully resolved?

- Has someone managed to create fake cards with fake money in it, or this is impossible by design?

an hour agoabdullahkhalids

How do you recharge it? Do you have to swap the battery?

6 hours agofph

Hey, developer here :)

I used an ultra thin LiPo, so you can actually charge it. USB is obviously not an option but it uses magnetic pogo pins on the back side ^^

5 hours agokrauseler

Try NGK EnerCera for battery.

4 hours agofrankest

__This__ is where all those trusted app parts should go - a smart card with e-ink display that can provide high security assurance level and where I won't mind that it's locked down because it has only one purpose.

__Not__ to my smartphone, effectively preventing me from modifying the system in the name of security. A banking app can use a card like this and on the display I could for example see where a transaction would go and then I could accept it, possibly even with a biometric identification.

This would enable me to keep my smartphone customizable and banking apps secure at the same time.

[apologies for the rant]

2 hours agozb3

It seems like it might be a little expensive for a business card...

8 hours agovoidUpdate

Let's see Paul Allen's card.

5 hours agobird0861

This is great, and I love it, and I hate to be saying this, but it's not literally the size of a credit card, it's 0.2mm thicker.

5 hours agostavros

Fair enough, but I acknowledged that and it's 0.24mm thicker if we want to be exact. Here's a quote from my Git Repo:

"Official ISO7816 smartcards are specified at 0.76mm thickness, but many real-world cards slightly exceed this in practice. The target for this project was simple: Stay around ~1mm total thickness and preserve the illusion of a normal card."

3 hours agokrauseler

Hey, works for me, I just got OCD from the title's usage of the word "literally".

3 hours agostavros

Can it run DOOM?

7 hours agoohlookcake

I've got the question like 100 times easily, and I love it.

And yes, if you accept ~0.7FPS

5 hours agokrauseler

You mean, 1.5 SPF :-D :-D

2 hours agomlmonkey

Run Unix v6 on it :) 16 bit and works with like 80kb of ram

6 hours agoiberator

First thought: cool! Second thought: e-waste

(same reaction as single-serve coffee pods, circa 2023)

5 hours agomrbluecoat

Good point. Ideally it would be the opposite of waste if it can save you from several cards. But banks would never certify such a multi-card system unless a big company pushes it forward.

Otherwise I'm sure people might use this to hack some terminals :P

5 hours agokrauseler

Do yourself it!

6 hours agothenthenthen

I want this, but only for one thing: email.

I already use an pwnagotchi, and it works great for this - but its a bit bulky.

If I can get this set up and working, it'll be my main interface to email.

6 hours agoaa-jv

legendary

7 hours agosuzukivenom

[flagged]

6 hours agopslab
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4 hours ago

[dead]

3 hours agoswordlucky666

[flagged]

4 hours agoflintenmuschi

It's not a computer.

6 hours agogoodpoint

It’s got more horsepower than my first desktop computer

6 hours agocbdevidal

In what way is it not a computer?

4 hours agobigfishrunning

Right, it doesn't compute. Apologies for the lie.

5 hours agokrauseler

Your definition of "computer" is incorrect.