Quote
Traumflug
Like @Kurzaa I think you're already pretty high on the feature list for a low end board. Not much more and you can simply copy the Duet.
Tramflug, thanks for your comments.
The only features I think I could remove and still have a useful board are the support for a 2nd extruder, and the support for optional digital stepper current control (restricted to just 2 channels, one to set XYZ current and one to set extruder currents). Support for a second extruder is something that RAMPS already provides. if you can live without a controllable cooling fan, and I think it would be a mistake to produce a board that does less than RAMPS. The only costs are for the connectors for the extra stepstick and extruder motor, a low-cost mosfet for controlling the heater, and 2 extra connectors on the terminal block. Total cost less than £0.50. Well worth it I think, especially given the rise of dual-nozzle printing.
The optional digital stepper motor current control is essentially free, because the microcontroller has a built-in 2-channel DAC, and the extra cost of 1 extra socket pin per stepper driver is tiny.
The main feature missing is Ethernet, because that does add a significant amount of cost.
Quote
Traumflug
A few words about what I observed about people's recognition over the years:
If you also offer a StepStick derivate with digital current control, people will likely recognize these derivates are required. The fact that Gen7 Opto Endstops exist makes most people thinking Gen7 requires Opto Endstops. Of course it doesn't, mechanical endstops work just as fine as on any other controller. With this in mind I'd stick to the pure Pololu form factor for the stepper drivers which is pretty much an industry standard now.
Thanks, however IME digital; stepper motor current is very valuable, and it's even more valuable for novices, who may not even have a multimeter. But I take the point: it needs to be made very clear that standard stepsticks work with the board. My hope is that the modified stepstick with an extra pin for current control would be adopted by other boards and eventually become a standard too.
Quote
Traumflug
Visual appearance is more important than technical facts. These large silkscreen logos on the back or similar. 4pi is recognized as "the controller with an entirely flat back". RepRapDiscount makes all its boards white (second silkscreen covering the whole board), for a more friendly appearance. Asking a friend with an artistic mind to put something nice, unique onto the board is likely a good idea.
Interesting, thanks.
Quote
Traumflug
From the Open Source perspective: doing the design in gEDA or KiCAD would be awesome. Both are entirely sufficient for such tasks and KiCAD is currently on a steep rise: [reprap.org]
I'm in favour of using open source tools as long as they are up to the job, so I started doing a board layout for this in KiCad. But I quickly found that none of the major SMD components or even most of the connectors I need are in the KiCad library, or any other libraries for Kicad that I could find. I don't have time to design them all. So unless someone can point me to KiCad libraries for these parts that I failed to find myself, or an Eagle to KiCad library converter, I will carry on using Eagle. But I'm keeping the size to within the 100x80mm size limit of the version that is free for individuals to use. It's a great pity that there is no universal XML format to describe components to PCB layout programs, if there were then the component manufacturers might produce these files themselves.