cnlohrcnlohr@chaos.social
Jun 29, 2026, 9:29 PMI cannot believe PCBBuy actually printed this circuit board.
Replies
Janajanamarie@mystical.gardenJun 29, 2026, 9:37 PM@cnlohr oh that is stellar! Is it a space filling curve? If so, how long is it??
- cnlohrcnlohr@chaos.socialJun 29, 2026, 9:52 PM
@janamarie It is a single line, but it is not a well-behaved space filling curve, it was solved iteratively.
- Janajanamarie@mystical.gardenJun 29, 2026, 9:58 PM
@cnlohr aah very nice! It looks very organic and also a bit polycrystalline
Jun 29, 2026, 10:02 PM@janamarie @cnlohr so it's a resistor? It must have a couple ohms at least. Maybe tens 🤔
rumirumi@corneill.esJun 29, 2026, 10:27 PM@piggo @cnlohr @janamarie hundreds: https://chaos.social/@cnlohr/116835616195513271
waaah- cnlohrcnlohr@chaos.socialJun 30, 2026, 5:15 AM
@janamarie I just realized I didn't explain - it's about 27 meters on the front and 19 meters on the back.
Moss (the τεχie) <(fsm)>{{Moss_the_TeXie@rheinneckar.socialJun 30, 2026, 12:26 AM@cnlohr
Interesting. May we see the algorithm, please?
jasegjaseg@chaos.socialJun 30, 2026, 7:58 AM@cnlohr If you're cool with it, if you publish your code I'd love to integrate it with my kimesh Kicad tamper sensing mesh plugin.
- cnlohrcnlohr@chaos.socialJun 30, 2026, 8:05 AM
@jaseg @janamarie It is miles away from a kicad plugin. I do intend to publish the code with the video though.
- jasegjaseg@chaos.socialJun 30, 2026, 8:07 AM
@cnlohr neat, doesn't matter if it's rough, I can neaten it up myself when integrating it into kimesh.
calxcalx@infosec.exchangeJun 29, 2026, 9:39 PM@cnlohr wooo this is so cool
nadjadequbed@mastodon.chaosfield.atJun 29, 2026, 9:39 PM@cnlohr given how much of a headache removing lots of copper is for PCB manufacture, you probably saved them money :P
- cnlohrcnlohr@chaos.socialJun 29, 2026, 9:52 PM
@dequbed They charged a good bit extra because it was a "coil"
- Janajanamarie@mystical.gardenJun 29, 2026, 10:03 PM
anyMouseanymouse_404@glitch.socialJun 30, 2026, 1:17 AM@janamarie @cnlohr @dequbed Why don't PCB fabs like pcb coils?
- Janajanamarie@mystical.gardenJun 30, 2026, 7:44 AM
@anymouse_404 @cnlohr @dequbed because fabs like to actually delivery you a working product of a certain quality level, basically they want to deliver what you ordered. This is an effort that varies with the 'complexity' of the board, e.g. feature size, milling operations, via size, via count, copper distribution, etc... A coil is extra complicated because it is just one single long trace, often with the smallest feature size (meaning tight tolerances) and it is quite tedious finding errors within coils. A coil with a few shorted traces shows up exactly the same on a flying needle tester as a non-defective one, but it probably wont be usable
- nadjadequbed@mastodon.chaosfield.atJun 30, 2026, 7:53 AM
@janamarie @anymouse_404 @cnlohr also you will generally use PCB coils for the kinds of frequencies where the tiny changes from board to board in what is essentially a stochastic process (etching) make a large difference.
cpressercccpresser@chaos.socialJun 29, 2026, 9:57 PM- nadjadequbed@mastodon.chaosfield.atJun 29, 2026, 10:15 PM
@cccpresser @cnlohr true true. Couldn't give a definite answer without a lot more information. Process costs like that are hard to put an exact number to ^^
Senilsenil@gts.social.senil.meJun 30, 2026, 5:31 AM@cccpresser @dequbed @cnlohr ENIG layers are like, atoms-worth of gold, it's barely anything at all.
IIRC it's mostly just the added process headache of doing it compared to HASL, which is much simpler in comparison (and uses leaded solder most of the time unless you outright request lead-free HASL which... why are you doing that instead of ENIG).
- cnlohrcnlohr@chaos.socialJun 30, 2026, 5:34 AM
@senil I probably could/should have used lead-free HASL, even though I normally use leaded HASL, I figure lots of people will be putting their fingers all over this one.
Jun 29, 2026, 9:42 PM@cnlohr Did they charge you extra for the all around everything ENIG, or was it sponsored?
- cnlohrcnlohr@chaos.socialJun 29, 2026, 9:52 PM
@ftg They did charge me extra! But I think it might be worth it.
- Jun 29, 2026, 9:57 PM
@cnlohr
Definitely looking forward to seeing this in action.
And if that's an SMA footprint at the edge, how does it look on the VNA? 
qwazixqwazix@bananachips.clubJun 29, 2026, 9:45 PM@cnlohr this is beautiful, what is it?
- cnlohrcnlohr@chaos.socialJun 29, 2026, 9:53 PM
@qwazix It's hopefully trying to be the world's dumbest matrix keypad, you need a TDR to measure.
penguin42penguin42@mastodon.org.ukJun 29, 2026, 9:58 PM
Graham Sutherland / Polynomialgsuberland@chaos.socialJun 29, 2026, 10:05 PM- cnlohrcnlohr@chaos.socialJun 29, 2026, 10:06 PM
@gsuberland @qwazix Well, this is what I have, so I guess I'll see what I see.
- Graham Sutherland / Polynomialgsuberland@chaos.socialJun 29, 2026, 10:07 PM
ChuckChuckMcManis@chaos.socialJun 29, 2026, 10:19 PM
Jun 29, 2026, 9:45 PM@cnlohr Looks a bit like Damascus steel from afar. What does it do?
- cnlohrcnlohr@chaos.socialJun 29, 2026, 9:53 PM
@jaj It is trying to be a really dumb matrix keypad, one I will need to do signal processing on to see what buttons are down.
calma como una bombatech_prole@hispagatos.spaceJun 29, 2026, 9:47 PM@cnlohr one could make all kinds of circuits on that thing
- cnlohrcnlohr@chaos.socialJun 29, 2026, 9:53 PM
@tech_prole It's one long, 200 ohm unbroken trace.
JaZoneJazone@theforkiverse.comJun 29, 2026, 9:47 PMIt's stunning.😍
- Jun 29, 2026, 9:51 PM
@cnlohr Interesting that your first picture has some artifacts, most notably straight verticle connections through the PCB curve. Some AI camera driver?
- cnlohrcnlohr@chaos.socialJun 29, 2026, 9:54 PM
@jaj Looks like AI Camera junk. But it didn't show up when I zoomed in on my phone. Thanks for pointing that out. I'll be sure to use a different camera.
luna the doggie :neofox_snug: :therian:lunareclipse@snug.moeJun 29, 2026, 11:09 PM
Jun 30, 2026, 8:29 AM- Jun 30, 2026, 2:31 PM
joeJoe_von_Saporski@bunt.socialJun 29, 2026, 9:56 PM@cnlohr wow :o
Peter Cockpjacock@fediscience.orgJun 29, 2026, 9:56 PM@cnlohr that is beautiful - but you’re underselling it with the alt text - that’s not just a “circuit board”, it’s a space filling curve based #MechanicalKeyboard PCB piece of art!
Lou.gkrnours@mastodon.gamedev.placeJun 29, 2026, 10:18 PM@cnlohr pretty
Eli the Beardedelithebearded@fed.qaz.redJun 29, 2026, 10:20 PMA-maze-ing!
Zeta Syanthiszetasyanthis@dragon.styleJun 29, 2026, 10:38 PMWhat is this? It's beautiful.
Ryanfullywoolly@mastodon.socialJun 29, 2026, 10:54 PM@cnlohr super cool! I see you're talking about using a network analyzer, but did you try getting a calculation of the parasitics?
- cnlohrcnlohr@chaos.socialJun 30, 2026, 12:04 AM
@fullywoolly Why calculate when you can measure?
- Ryanfullywoolly@mastodon.socialJun 30, 2026, 12:07 AM
@cnlohr if it ideally meets your needs before ordering?
- cnlohrcnlohr@chaos.socialJun 30, 2026, 12:38 AM
@fullywoolly It's impractical to know what the real world effects are going to be on a design like this. Gotta just try.
- Ryanfullywoolly@mastodon.socialJun 30, 2026, 12:53 AM
@cnlohr I guess. With several years of differential equations and numerical methods I think modeling is cool for its own sake.
- cnlohrcnlohr@chaos.socialJun 30, 2026, 4:02 AM
@fullywoolly I'll try to get more of the content available publicly as I get further along this project.
- Ryanfullywoolly@mastodon.socialJun 30, 2026, 4:19 AM
@cnlohr no biggy. If it isn't important to you that's really ok. It is pretty to look at all the same
Jun 30, 2026, 12:16 AM@cnlohr @fullywoolly the length of that track must have measurable resistance? Could you tell which key just on change of resistance?
- Ryanfullywoolly@mastodon.socialJun 30, 2026, 12:19 AM
- cnlohrcnlohr@chaos.socialJun 30, 2026, 12:39 AM
@fullywoolly @revk I got it wrong. Front: 137, back 77
