So I've been visiting multi extruder for Ramps 1.4 page (
https://reprap.org/wiki/Adding_more_extruders) for quite some time (just browsing). And then I faced the challenge: How synchronously, reliably, and on a budget control 4 Z motors of my printer.
I did try serial and partial serial (2 parallel pairs of 2 motors in series) connections - they work even with 12V PSU, but I had this idea that it may be done better. So I looked at stepper expanders.
Among all stepper expanders most promising and cheap was Arduino CNC shield (which is currently is listed on Amazon 2 for $7). So bellow schema works, despite the fact that I burned one KFB 2.0 by connecting to the wrong pins (so now you may estimate my familiarity with electronics). I want to run this by you guys so you may point to me what I am missing.
I know that I do not need two ground wires - one is enough.