Jon's Place

Tuesday, January 28, 2014

Custom MicroPython Board

One of the things I've been working on in my spare time is a new board for uCee. I was originally going to use the actual MicroPython board that I will get from the KickStarter campaign, but I decided to build my own instead for a couple reasons:

  1. It will fit better, and be easier to connect everything to
  2. I want to start playing with more advanced micro-controllers, and building your own board is definitely a good way to make that happen
The other thing I decided after my work-related adventures with the ammeter board, is I wanted to use a PCB design tool that can generate the PCB with the appropriate connections from a schematic. Most hobbyists use Eagle for that, but I absolutely detest the user interface, so I decided to try a different package, namely KiCad. The user interface definitely takes some getting used to, but once I figured out most of the idiosyncrasies, it is quite usable.

Damien George (the guy behind MicroPython) very nicely published the schematic for his latest revision of the MicroPython board, so I shamelessly copied what I needed and added my own parts that uCee needs, and I ended up with something that should work.

Here's my schematic:

And here's what the PCB looks like, first with the bottom layer hidden (which makes the top much more understandable), and then with the bottom later visible:

KiCad can also show you a 3D rendering of what your board would look like, but you have to supply 3D models of any custom parts you include. My board has a whole pile of parts that I had to create my own footprint for (usb connector, uSD connector, all the Hirose DF-13 2, 3, 4, and 6-pin connectors, etc). So I went to the manufacturers website, and found CAD files for most of them, and the imported them into Rhino, scaled and positioned them correctly, and then exported them as STL files. Wings 3D, although nowhere near as capable as Rhino, has a WRL exporter that KiCad is designed for, so I imported the STL models into Wings 3D, colored them, and exported them as WRL files. I then applied the 3D model to each component footprint, which allows me to generate this:

All in all, not bad.

I plan on sending in this board to get made later this week, so hopefully I'll have my own MicroPython board inside uCee within a couple weeks.


  • It seems that a lot of people build their own KiCad libraries of parts and footprints. I wonder how hard would it be to have the work that you did imported into the default KiCad library, for everybody to use.

    And what it would take to make the process easier, in case it isn't.

    By Blogger Unknown, At December 19, 2014 at 7:28 AM  

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