having built my own Gocpi machine from the minimalist kit, I was looking at different ways to control it apart from using the go software, as I'm already running a polargraph machine with a Pi running the minimalist interface.

https://www.makebournemouth.com/?p=831 Whilst browsing, I saw that Brian Innes from the Bournemouth Makerspace had done a rewrite of the Gocupi software in python, and apparently had rolled in some extra functionality and a GUI.

Hi code is available on GitHub, although I'm not exactly sure of the hardware he's using. I'm going to try it out and disappear into the rabbit hole that is sorting out a new controller for a polargraph machine. https://github.com/brianinnes/pycupi

I am pretty sure the gocupi setup is nothing more complex than a usb serial link to an optimised firmware on an arduino. If you're using a Polarshield, you'd need to update the stepper driver pins

https://github.com/brianinnes/pycupi/blob/master/arduino/StepperDriver/StepperDriver.ino#L11-L18

but can't think it'd need much else.

It's a bit frustrating that it's branded polargraph (cos it's not a polargraph), but otherwise it's a very nice solution I think.

The direct serial connection of an on-board arduino is a nice way to avoid the cost of USB hardware. Coupled with a cheap pi, there's a pretty compelling platform. Use a smartphone instead of an on-board touchscreen.

sn

Quote from hashampersand on March 19, 2016, 12:59

https://www.makebournemouth.com/?p=831 Whilst browsing, I saw that Brian Innes from the Bournemouth Makerspace had done a rewrite of the Gocupi software in python, and apparently had rolled in some extra functionality and a GUI.

Hi code is available on GitHub, although I'm not exactly sure of the hardware he's using. I'm going to try it out and disappear into the rabbit hole that is sorting out a new controller for a polargraph machine. https://github.com/brianinnes/pycupi

Hi hashampersand,

Pycupi doesn't have a GUI. Its all done by editing python scripts.

The electronics is my cheap and cheerful dual stepper board. http://bit.ly/1o5OfrI (It was meant to be cheap to build and work with the Polargraph firmware and also my Eggbot/Spherebot and any other interesting two stepper drawing machine that I might want to build).

I gave away some PCBs at MakeBmth and now we have Pylargraph (https://github.com/MarkJB/pylargraph) and Pycupi.

No need to un-polargraph-ise everything, some of the things are genuinely useful for Polargraph too - they're machine agnostic, and I admit I'm secretly proud that the name gets such widespread use 🙂

So I'm not too precious about the name being used, and I'm not that concerned about brand protection as such - more about the opportunity of creating a little confusion and suggesting an interchangeability that might get people stuck, and unable to explain their problem.

I'm just imagining a long troubleshooting conversation with someone who has bought a Polargraph machine, and struggled to get it to work, when they finally reveal they're using "a controller for a polargraph" rather than the Polargraph controller, and the command format is different for each kind.

Not sure of a better way to differentiate though - I really like the cross-pollenation and don't want to discourage that. Actually the reason that I've never really challenged the use of "polargraph" with gocupi, it was so clearly such a good project that polargraph benefits from being associated with, and it was only ever used descriptively, and with a small P. However, some other machine makers sold their machine as being "the newest version of polargraph", which makes sense if you think polargraph is a generic name for a drawbot (well, as much sense as marketing something as "the newest version of 3d printer" would anyway), but if you think it is a trademark or a brand name (which it is), it becomes "passing off", implying a relationship where there is none ("the newest version of arduino"). Well, I'm not in a position to ever prosecute a legal case for that kind of misrepresentation (even if I was that way inclined), but the harm of misrepresentation is that buyers don't know where to get help and then they have a bad experience and then they learn that it's risky to support hacked-together (er open source) projects in the future, and that hurts us all.

So aye, just think twice about how people will read your sentence - if you think it might indicate a compatibility with polargraph software rather than just being suitable for a polargraph-type machine, then couch it in different terms. Pylargraph is good as a fork of the project.

I am very happy to be associated with pycupi, and there is no supremacy implied or disrespect intended.

ta!
sn