Muxcard, a dyi credit card size computer

(github.com)

162 points | by sargstuff 3 days ago ago

47 comments

  • mabster an hour ago

    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!

  • cbdevidal 3 hours ago

    What fun!

    I’d love to also go the opposite direction, a full-sized laptop with an ESP32 running tiny386 and Windows 95 ^_^

    https://www.hackster.io/news/he-chunhui-s-tiny386-turns-the-...

  • lxgr 2 hours ago

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

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

    • ZiiS an hour ago

      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.

      • lxgr 16 minutes ago

        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).

      • IAmBroom an hour ago

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

        IO is of course required.

  • asdefghyk 6 hours ago

    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

  • krauseler 3 hours ago

    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?

    • Muhammad523 3 hours ago

      > 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..

    • IAmBroom an hour ago

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

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

  • z3ugma an hour ago

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

  • gnabgib 3 days ago

    Last week (87 points, 7 comments) https://news.ycombinator.com/item?id=48251528

  • firesteelrain 2 hours ago

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

  • inflam52 2 hours ago

    I love these kind of projects. M5Stack Cardputer Zero launched on Kickstarter last week and already hit their goal

    https://www.kickstarter.com/projects/m5stack/cardputerzero

  • WithinReason 3 hours ago

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

  • frankest 2 hours ago

    Try NGK EnerCera for battery.

  • rbanffy 5 hours ago

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

    • WithinReason 3 hours ago

      That actually exists, with even the same CPU but no NFC: https://www.xteink.com/products/xteink-x4

    • jansan 5 hours ago

      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.

      • rbanffy 4 hours ago

        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.

  • mmmehulll 4 hours ago

    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

    • resonious 4 hours ago

      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.

  • fph 4 hours ago

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

    • krauseler 3 hours ago

      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 ^^

  • stavros 2 hours ago

    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.

    • krauseler an hour ago

      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."

      • stavros an hour ago

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

  • voidUpdate 6 hours ago

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

    • bird0861 3 hours ago

      Let's see Paul Allen's card.

  • iberator 3 hours ago

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

  • ohlookcake 5 hours ago

    Can it run DOOM?

    • krauseler 3 hours ago

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

      And yes, if you accept ~0.7FPS

      • mlmonkey 4 minutes ago

        You mean, 1.5 SPF :-D :-D

  • mrbluecoat 3 hours ago

    First thought: cool! Second thought: e-waste

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

    • krauseler 3 hours ago

      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

  • thenthenthen 4 hours ago

    Do yourself it!

  • aa-jv 4 hours ago

    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.

  • suzukivenom 5 hours ago

    legendary

  • goodpoint 4 hours ago

    It's not a computer.

    • bigfishrunning 2 hours ago

      In what way is it not a computer?

    • cbdevidal 4 hours ago

      It’s got more horsepower than my first desktop computer

    • antonvs 2 hours ago

      Your definition of "computer" is incorrect.

    • krauseler 3 hours ago

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