GAUPS: a new stepper driver shield for CNC milling machines

[cvoinescu]

GAUPS 1.0 (GRBL and Arduino Uno-compatible Pololu-compatible stepper motor driver Shield -- like RAMPS, but for CNC milling machines) is a derivative of Bart Dring's buildlog.net Arduino-compatible stepper shield. Thank you, Bart! The schematic is almost the same (there aren't many ways of connecting three or four Pololu drivers to an Arduino Uno running GRBL), and the board layout is very similar (given the Arduino shield connections and board outline, there aren't many reasonable choices here either). However, I designed the PCB from scratch. I routed it by hand, with a wide motor supply trace, and almost all connections on the front of the board, leaving the ground plane on the back almost uninterrupted.

The kit (PCB plus all the components) is available in my store, and here are the assembly instructions (nicely illustrated, if I can say so myself). The bare PCB is available too.

The design is open-source, and I will upload the KiCad schematic and board files as soon as I have a chance.

Edited to correct attribution (see discussion below). The original post said "GAUPS 1.0 [...] is loosely based on Bart Dring's Arduino-compatible stepper shield."

[peter_]

The board quality looks wonderful, and the pictures look gorgeous -- well done.

Open source hardware is very much about building a community and ecosystem of free exchange, both to share ideas, make things accessible, make it possible to learn from others' works, and make it possible for projects to be improved upon through derivative works. Often the very only thing that a content author asks for is attribution, and the only reward they see are folks making productive use of their content for all sorts of great purposes.

This is very clearly a derivative work of Bart's Stepper Shield, which was released as CC-BY-SA. The bill of materials, part placement, and function are nearly identical, the only difference is in the routing (to have a solid ground plane) and changing the row of jumpers to a DIP switch array. It is your responsibility to very clearly provide attribution to the original content author (by saying it's a derivative work of project X by author Y) on the board/website/etc., with the following modifications in the documentation: "1) The power trace width was increased for greater stability, 2) The microstep jumper array was changed to a dipswitch array to ease configuration". These are significant contributions. But it is not okay to say that it's only "loosely" based on a CC-BY-SA licensed work when it's clearly a nearly identical copy in every way, and to not provide attribution.

http://creativecommons.org/licenses/by-sa/3.0/legalcode

[cvoinescu]

I will change the description because I don't mind giving Bart credit (and royalties, which I was going to do anyway), but I think it's debatable whether it is technically a derivative work. As I said, given the requirements (four drivers in that outline and with the default GRBL pinout), there aren't many options for part placement that make sense, so the boards are going to end up looking more or less the same. I did not use Bart's schematic and board files, nor did I look at his board for inspiration for the routing, hence "loosely". A similar case would be the Pololu A4988 drivers and the open-source StepStick drivers. The schematic is nearly identical, the BOM is very close, the layout is very similar, the function is roughly the same, but the PCB is designed independently for the two. Since the Pololu driver is not open-source, if the StepStick was a derivative of the Pololu module, it would be infringing on Pololu's copyright.

Still, because my shield and Bart's look nearly identical, I'd rather err on the side of more attribution, rather than less.

So, you're right, and thank you for being kind about it. I have edited the post, and I'll fix the documentation tonight.