2017-05-23 3:27 GMT+02:00 Luke Kenneth Casson Leighton <lkcl@lkcl.net>:

hi all,

ok so i've been looking around and the practice of creating a
"modular" 3d printing electronics board is extremely common, thanks,
many years ago, to the stupid, stupid decision to use prototyping
(evaulation) plugin boards with 1.3 to 2.0 *amp* stepper ICs mounted
onto micro-postage-stamp-sized PCBs. the problems these cause are
endless.

You're being a bit brief here. But essentially, the community has been using "default" boards, which are cheapish and fairly documented/understood, but too generic and thus not able enough?

so instead of an on-board ATSAM4, you use an arduino due. instead of
WIFI you use a *standard arduino WIFI shield*.

Read about a guy RE'ing "hoverboards" and he's creating an OSS firmware replacement for these, which seem to be desinged around the fafourite STM32F*.

https://opensourceebikefirmware.bitbucket.io/About_the_project.html

But how about the ESP32? (Successor to the ESP8266). Reasonable beefy CPU with build in WiFi. The Duet is using the ESP8266 as the WiFi bridge.

now, debatable is whether to split out the MOSFETs, endstops and
thermistors into their own separate shield as well, which i feel might
be sensible.

Why not place all controllers separately and direct to their HW and connect them via a bus? This gives you freedom to expand and replace. And use a EOMA card as the "master"?

Or would that kind of modularity up the costs too much?