Knob/Button PCB Shield

#1

Hi, first post here...
I was thinking of making a simple PCB with a few knobs & buttons; put pin headers into the back of the board, a kind of 'shield' above the back of the board, maybe use the SDA or JP1 headers as a physical reinforcement. Maybe 4-6 knobs, 2-4 buttons, a few LEDs? Essentially the Nord Micro Modular interface, but without the 7 segment displays.
Questions:
1. Is anyone else doing this? I'd rather just buy one if I can!
2. Are the eagle files for the PCB available anywhere - couldn't see them, would make the process slightly easier re: matching up the headers.

#2

Love the idea!
I haven't made the eagle files available so far. I'm all for opening but my concern is that it makes it easy for professional rip-offs that do not support or contribute to development. But I don't want to make it more difficult than necessary to develop extensions. So as a compromise I'm strongly considering publishing an incomplete eagle file that includes the board outline, GPIO pads and connectors. I believe that would provide everything you'd need to design such a shield, right? Give me a couple of days to publish this.

For support/reinforcement, perhaps it is better to mount on the bottom side, and use spacers on the mounting holes. Only supporting with the X3/X4 pin headers may be a bit weak.

#3

Thanks Johannes - that would be great - could you include all the board headers, mounting holes and all the connectors - but miss out the 'difficult bit' in the middle!

I'll experiment with the positioning

Understand your concerns, I've seen the benefits of CC-BY-SA license in my work at http://musicthing.co.uk/modular/ and - on a much bigger scale - with Mutable Instruments.

#4

Is it a coincidence that the Axoloti Core is exactly as wide as the largest possible board in the hobbyist version of Eagle? :wink: :wink:
(I only say this because I was so relieved that my version of Eagle can make a PCB the same size as Axoloti)

#5

160mm? EuroCard is a standard. Fits some alu extrusion enclosures. 160mm is required for the connectors, the only way to make it smaller is using multiple sides for connectors. I have a commercial standard license of eagle 6, that is limited to 160x100mm indeed.

#6

I would certainly appreciate published front & power connector positions and dimensions, too. I could use it for a more accurate case design.

#7

I don't know how it work's for you on Music Thing (I though it was ok), but Mutable instruments is one of the biggest examples of how open licenses can work nicely. IMO Olivier's work is a big lesson of open licenses. No need to use it as an example of the opposite.

#8

Sorry, that's exactly what I was saying. Mutable & MTM both show how CC-BY-SA licenses (with commercial use permitted) can be very useful.

Olivier is doing very well selling readymade modules with CC-BY-SA licenses that also permit a hobbyist community building DIY versions and selling PCBs. I think it's a very positive model that has created a strong community creating alternative firmware etc.

I don't sell modules or kits at all, but my license has allowed others to sell and distribute kits or finished modules (Thonk, SynthCube etc) of my designs. My main goal has been to get my designs used by musicians, and that's working very well.

I just said that I understand Johannes' concerns, because many people are nervous about CC-BY-SA models, fearing piracy or rip-offs. I personally think that with a BOM as complex as Axoloti, and a relatively niche audience, this might not be a big risk.

There's also a lot you can do with brand names etc; Anyone can make and sell a finished clone of a MI Clouds, but they can't (I don't think) call it "Mutable Instruments" or "Clouds" or use the cosmetic design. That's how Arduino have worked (you can make a CloneDuino, but not an Arduino) although they obviously now have their own problems closer to home in Italy...

#9

now I understand. : )
I think the same.
No real danger in publish the files. Arduino is also a good example.
Copy is part of the game of the open hardware.

#10

Hi everybody!,

I've started something similar, except I was thinking to use 16 pots and 4 buttons.
I just like knobs :wink:

Johannes: I don't need Eagle of the PCB, only a dimensioned drawing showing the location of the strip of GPIO. I assume they're @ 2.54mm and in a straight line, so if you simply indicate the location of the RIN- pin from the edges of the board, I can figure out the rest myself and you don't have to worry about creeps cloning your boards.

I'll publish my stuff here once I've gotten a little further down the path.

Have fun!

#11

I wouldn't mind a hobbyist building an Axoloti Core clone. Even if gerbers and BOM 'd be made public, I believe really few people are likely to assemble one by hand. It is possible but not economical to build a small number of boards. Axoloti Core is just designed to be manufactured on an industrial pick and place production line.

Arduino - when it started, it was a relatively small effort : "Wiring" software, very simple board design, and some "poison" mixed in, the 0.6" pin header offset "mistake" seems to me a decision driven by a "gillette-effect" business model.

#12

Here's an Eagle BRD with the mechanically relevant parts
axocore_v11_mech.brd (104.9 KB)
I believe this contains everything you'd need to design extension boards.

Axoloti Core PCB diagram
Designing Backpack/UI Board
#13

Thanks a lot!
A front view of the connectors would be useful, too. Is that possible?

#14

I just read this after asking about the Doepfer USB 64 board and I know a few DIY people who fear having their work pinched by a certain synth company, sadly their stuff is terribly obscure because of it. How about something attaching an NDA and a license agreement to each core sale. I for one would pay to develop a breakout board to get things moving for myself. Yhere may be a collective feeling on points like this.

#15

Thanks for making the board, It's really cool.