Here is a stab at the Arduino compatible Sanguino board (albeit simplified). It’s pretty standard except we’ve removed the reset circuitry and alot of the pins. We still have 4 controllable pins, one for the LED and three spare for something fun in future. Once again the plastic was printed before dropping in pre-tinned components and finally printing the metal tracks. I have previously done some tests which show we need to have a radius on each corners of printed tracks, ideally at least 1.5mm, but for compactness I squared these off resulting in poorer quality but nevertheless its quite a big step forward from where we were a few years ago. Four extra tracks are required on a second layer to get the circuit fully working; I’ve done this manually for the time being. In addition I had to manually solder in 2/3 pins as the track had not connected properly, however I think I can correct this by extending sections of track beyond their required endpoints and utilising the bigger radii at corners that I’ve already mentioned. It’s still a little blobby, but nevertheless here it is working running a simple blink program, although we can still reflash the chip to do something else with the spare pins.
Really impressive work. It will be interesting to see how fine of tracks can be printed as the process gets fine-tuned. Maybe someday we will all be able to make multi-layered 3D printed circuit boards at home.