A self-powered computer in actual credit-card size (~1mm thick) - https://news.ycombinator.com/item?id=48251528 - May 2026 (11 comments)
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
<https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...>
.... trouble was they would often 'misfeed' when using a tray style CD Rom drive and jam in the mechanism, meaning you had to dismantle the drive to get the card out.
Understandably, this would quickly piss off people you gave the card to. This helped make the cards rather unpopular.
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?
I know it was intended as a joke but still..
3 old micro ibm hard drives combined into rgb color space / diy laser image projector[1] might be able provide a bigger picture without exceeding DIY credit card size. kinda depends on laser size.
Ummm... a smartphone internal projector module more compact than diy stack of ibm microdrives / laser.[2]
Not worrying about size: esp32 laser dac : https://www.youtube.com/watch?v=9YASnlB_t_U
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[0] : diy laser video projector : https://asktheman.xyz/
[1] : https://www.youtube.com/watch?v=fEPicBSYeNQ
: https://www.youtube.com/watch?v=bl1e54QGJk4
Teenage Alan T. would be so disappointed... :D
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If it can fetch/display files from the internet, yes, it can run doom[5]. Or make use of curl, curl-doom[18]
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stripped down doom can run in 4MB (doom on a smart toothbrush[7]). ESP32 has support for up to 4MB external PSRAM[1]. ESP32 port of doom[2]. lcd screen might provide for faster refresh / less blury images under magnifying glass.
Alternatively, adding an expansion port to be able to use 'doomchip' might make it easier hide game play while at work[8] / stay awake between screen frame refreshes. (and/or simulateously play tetris & 1d pacman; add Badgey functionality[19] )
But should one go with micropython[3], reflectionsOS[4] or not waste space and use a 2 stage 512k bootloader for dns.doom[5]?
contikiOS[6] for dns.doom[5] might be the correct fit without needing to add 4mb psram / doomchip expansion port(s).
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Misc doomchip information:
doomchip non-tech article(2020)[11].
doomchip developer comments[12]. Should be able to get at least 2fps!
doomchip better expanded upon in a 'heads up, 7up' thread -> slice[9]/doomchip[10].
Surprised there's no dns doom.wad / I.D.Software Application (IDSA) rfc "Spit.wad: A DNS string encoding using Unicode for doom.wad graphics" version of rfc3492: "Punycode: A bootstring encoding of Unicode for Internationalizaed Domain Names in Appliations" (IDNA) [13]
(IDSA) rfc might permit formally unifying things like unicode-line-stacker[14], stacked diacretics generator[15], unicodeart[16] and "awesome symbols and characters in a bash prompt"[17].
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[0] : "Can it run doom?" : https://canitrundoom.org/
[1] : https://docs.espressif.com/projects/esp-idf/en/latest/esp32/...
[2] : https://www.techeblog.com/doom-electronic-badge-emfcamp/
[3] : https://github.com/NoosaHydro/2.4inch_ESP32-2432S024/tree/ma...
https://github.com/wojciech-graj/cydoomgeneric
[5] : https://undercodetesting.com/dns-can-run-doom-how-2000-dns-r...
[6] : https://contiki-os.org/
esp32 https://github.com/contiki-ng/contiki-ng/discussions/3022
[8] : https://hackaday.com/2020/05/13/the-doom-chip/
[9] : https://github.com/sylefeb/Silice
[10] : https://github.com/sylefeb/Silice/blob/master/projects/READM...
[11] : doomchip article : https://www.techeblog.com/doom-chip-game/
[12] : https://threadreaderapp.com/thread/1258808333265514497.html
[13] : https://www.rfc-editor.org/info/rfc3492/
[14] : https://github.com/axesilo/unicode-line-stacker
[15] : https://codepen.io/lingyloll/pen/ooMaYO
[16] : https://www.unicodeart.com/gallery/
[17] : https://unix.stackexchange.com/questions/25903/awesome-symbo...
Yes it's still impressive either way, I'm not debating that.
Nit: A (chip) credit card is already a fully working computer :)
> 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).
The interesting thing about this project is that this computer can function independently within a credit card sized space.
IO is of course required.
Perhaps the 'city block' heaters requiring similar sized AC condensors to provide control over Maxwell's daemon was the inspiration for the unix daemon process.
Optical computing makes fuzzy computations so much easier -> outgassing[2]
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[0] : https://spectrum.ieee.org/the-birth-of-ram
[1] : https://bunkerofdoom.com/lit/CRT-scopes/CRT_memory/index.htm...
[2] : https://spectrum.ieee.org/adhesive-outgassing-nasa-standards
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-...
Was turned into something commerical (?2002[2])[1]. Perhaps modern version would be the old AMD cyrix chips?
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[0] : http://boole.stanford.edu/cebit/
[1] : https://megagames.com/news/matchbox-pc-smallest-world
[2] : https://ptacts.uspto.gov/ptacts/public-informations/petition...
[3] : https://www.paloaltoonline.com/morgue/monthly/1999_May_26.MI...
And yes, if you accept ~0.7FPS
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.
- 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?
So, no AI seagul training to do machine banking/swipe money transfers.
__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]
"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."
Works on the RISC-V 32-bit processor, sometimes.
(same reaction as single-serve coffee pods, circa 2023)
Otherwise I'm sure people might use this to hack some terminals :P
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...
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I salute you sir. Did you have a better solution for later versions?
Catchy, higher order point/fundamental theory of calculus application of "Move over cassette tapes, adhesive tape has memory, too"[4]
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[1] : "Making a 3d printed circuit board that works" : https://www.instructables.com/Make-a-3D-Printed-Circuit-Boar...
[2] : pick-n-place machine : https://en.wikipedia.org/wiki/Pick-and-place_machine
[3] : No solder! : https://www.electromaker.io/blog/article/affordable-pcb-prot...
[4] : "Move over cassette tapes, adhesive tape has memory, too" " https://news.ycombinator.com/item?id=48161242
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 ^^
Perhaps also basis for a table coaster 3d hologram[1]
Adding to card thickness / modularity:
pop-up hologram display.[2][3]
projected keyboard/display[4] & gain ability to respond to text messages!
[0] : https://www.instructables.com/Smart-Glasses-V2/
[1] : https://www.youtube.com/watch?v=xHbQRcIWxC8
[2] : https://www.youtube.com/watch?v=vRo8m_a6F54
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.