PCBs Without Any Substrate

[Kimio Kosaka] is taking the concept of free-formed circuits to the next level with O’Baka Project No.7. It’s a fully functioning Arduino board, without the board. The traces are there and provide all of the support for the rest of the hardware. You can imagine the fragility of the package so it won’t be a surprise to learn that O’Baka Project means ‘stupid’ project.

We don’t think this manufacturing process is completely worthless. The ‘board’ seen above looks quite interesting and might be a good idea when building a show-piece where you want the circuitry to be seen. [Kimio] describes the process he used to achieve this look. The first step is to design a single-sided circuit board; he used EagleCAD. After printing out the traces he used 0.46mm steel wire to trace out each connection. Now heat up that soldering iron – [Kimio] recommends using high-acid flux to ease the process of soldering to the steel.

We think this would nicely compliment projects like LED cubes that use the circuit itself as a support structure. See this Arduino alternative from several different angles in the video after the break.


[Thanks Eric]

52 thoughts on “PCBs Without Any Substrate

  1. Yeah I know everyone’s gonna say “not a hack”. But still impressive in kind of an artsy way.

    And he didn’t even name it the “Skeleduino” or something.

  2. I’ve read over and over that you should never use acid core solder for electronics. This guy is using it. What is the downside? Will the ICs disintegrate at some point?

  3. For micron-thin copper traces of a PCB, acid core solder can eat away the trace itself. (When you etch, you use a strong acid to remove the unexposed PCB material.) But for thicker steel wire, it’s not as much of a concern.

  4. @fungus
    It is actually based on the Metaboard, which implements the USB connection in the bootloader code. Calling it an Arduino is a bit misleading as it isn’t technically 100% compatible.

  5. @fred
    The reason to not normally use acid core solder is the acid will eat the leads, and destroy the parts, IF the core isn’t completely cleaned off the parts. This is very dificult to do completely, especially if you are using stranded wire, or a circuit board, where there are lots of tiny places for things to hide. The metals we typically use for electronics don’t need nearly as agressive of a flux to clean them. Resin core effectively doesn’t need to be cleaned off.

  6. Wait a minute — this is no sort of bad idea. If you use insulated wires wherever possible, then you could probably wrap it around whatever you intend to install it in once you’ve fully tapped out the hardware and software.

    Imagine that, like those ‘slap bracelets’ from the 1980s. Just “stick my microcontroller board on here” *wham* done!

  7. It’s a goofy project, but we’ve seen many uses for this sort of thing before.

    -It may be harder to build like this, but it’s a lot cheaper than having a single board printed.

    -It’s flexible. There’s no reason you can’t easily adjust the shape of this thing to suit your needs as you’re building it. That might mean stuffing the circuit into a much smaller package.

    -It’s adaptable: You could embed it in concrete, epoxy, plastic, fiberglass, carbon-fiber, etc. You could even paper-mache it.

    -It’s easily dismantled: Just clip some wires and you’re down to basic components.

  8. So many people reiterating the same comment “Hurr durr, no p and no b!”… Reading comments before posting might be a good idea sometimes ya know.

    Apart from that, this is a very nice project :) Quite original. I feel this is more art than practicality but seeing how many hacks are used for purely decorative purposes these days that isnt a bad thing :) Keep up the good work, also, seal it in epoxy and market it! I’d buy one.

  9. Heh, I think it’s a hack in the classic definition of the word- taking steel wire and using it for something it wasn’t intended for: in place of a PCB. If you don’t think that’s a hack, just imagine Macgyver making one of these out of some chicken wire when he doesn’t have a substrate to work with. XD

  10. Granted, I don’t know much about the power requirements for the Arduino. But my first thought was the lack of any heatsink, be it an actual heatsink or metal under-layer as on a typical board, for the voltage regulator.

  11. I did this once to make a video inverter board.

    Worked fine for ages, got bored with it and scrapped it for parts.

    Its a good prototyping technique if you have a lot of recycled parts with short leads and want to try out different configurations quickly as it becomes trivial to detach resistors etc without wrecking the tracks on a PCB.

  12. @mowcius
    some more info on the alarm:

    it is a atmega8 controller, a speaker from a broken mobile phone , a 2×16 char display and some spring steel wire. (and some resisors, and other small parts)

    unfortunatly i dont have the source any more because that was on a harddrive which is broken :(

  13. Acid no go. Just steel wool or grind with a fine disc in a moto tool, REALLY CLEAN the steel wire. Use good regular paste flux for electronic use. Fine gauge piano wire is great for this, very strong for the gauge. To cut, don’t ruin your dykes. Bend sharply twice and snap, or nick first with grinder disc.
    Study the Art Deco of the 20’s 30’s for ways that tech first blended with art, all in good taste. Style circuits. 2 or 3d. Another potting source, strip-able weatherstrip caulk in clear.
    This can cram in amp into a headphone device pod etc many uses!

  14. An easy solution might be to use copper-coated steel wire.

    You can pick up a roll at any big-box hardware store. Look for MIG welding wire (the type without the flux core). Not all MIG wire is copper coated, but it should be easy enough to find.

    It’s also useful for antennas.

  15. You don’t need to use steel wire at all for this; all the wires are terminated on copper terminals. You can get stiff pre-tinned copper wire that looks the same, will solder with normal rosin core solder, is plenty strong enough and looks almost exactly the same.

  16. One more step, and its actually a very rugged construction method. If you took apart an early 60’s missile guidance system, you would find modules that were the same skeleton construction, potted in clear plastic, so they wouldn’t move.

    One other difference, instead of soldering, all joints were actually spot welded.

  17. Although it might not be the most stable or beautiful, these would make an excellent teaching aid for people getting into digital or simple circuits. It presents itself much more like a schematic than finished product while allowing interaction and easy access analysis.

  18. Why not use regular copper (plated copper) bus wire and be done with it?? Yeah, a little more fragile, but hey, lot easier to solder and you don’t need to use acid flux with it.

  19. now that is ART!

    @ acid flux babies: you clean it with metholated spirits… and/or WATER… and a toothbrush. Too lazy? so soak it! sheesh. Someone might think you’ve never done it before.

  20. @goaran: waycool!

    Tip: If you’d called it X-duino, where X is an obvious reference to what you project is doing and showed a video of you having sex with it (or just flashing an LED) THEN it would have been accepted and may have even been a featured article.

    I agree your way is better ;)

  21. Interesting take on point to point wiring. If you really want to see some well done designs look at old electronics of the vacuum tube era. There were high power transmitters, even televisions, made up of nothing but wires soldered from one point to another. The routing was tedious to do but it worked. Not sure who came up with the PCB idea. I know things went from point to point, then terminal strips, then wire wrap + solder, then pcb.

  22. I’d have been considering a higher guage copper than the steel — easier to solder to, and probably more attractive…

    The idea of sealing it in some form of hard resin is cool too — build the layout, then encase it. I wouldn’t suggest epoxy as it yellows badly with age, but a polyester mix like that made by “Castin Craft” would probably work great.

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