Mats Engstrom has shown a few 3D circuits lately too: a Little Wire programmer circuit built boardless with SMD components (at left) and encased in resin, and a Freeformed Nixie Tube clock with a beautiful radial design inside a box-like frame.
"Arduino Skeleton" board under "O'baka Project" which he says: "means a stupid project. This project is to make things which is not art and which is not usable. Now, I am making Arduino skeleton by using steel wires." Hmm, they look like usable art to me! Maybe a mis-translation. He lists instructions:
His "One Chip Arduino" has no board either, stressing economy.
How to make.
- Design single side PCB by EAGLE-CAD. (Base circuit is Metaboard)
- Print out this PCB pattern.
- Trace this PCB pattern by steel wire. (0.46mm in diameter)
I used a flux of the strong acidity for the steel wire soldering.
I find more examples the more I look, like this 3D alarm clock, video about using a CD as a circuit board, and Make: uses the tag "freeform" for freeform circuit layouts on its blog.
These inspired me to make one of my own, which turned out to be a faster, easier, cleaner way to make a simple 1-off circuit than home etching or point-to-point soldering, if the process is refined.