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3D Printer and Engraver Controllers

To take advantage the economies of scale we borrow certain hardware from the the popular hobbyist 3D printer and engraving fields for controlling our telescopes:

  • The Wemos R32 with CNC V3
    • This would be my first choice for an basic low budget OnStep build but my advice is to just keep it simple...
      • Use the built-in ESP32 Bluetooth support for now and skip the Smart Web Server.
      • Use LV8729 or S109 stepper drivers (no fancy wiring for SPI TMC drivers and they fit the budget.)
      • Skip the ST4 port (live with the Android App for control over BT.)
      • Don't bother with the DS3231 RTC (the date/time can be set from whatever is controlling OnStep anyway, the Android App for example.)
      • Run at 12V.
      • If you want everything but the kitchen sink, consider building a MaxSTM3.6 where its all been thought out.  Or use the S6.
    • Best to use traditional StepStick drivers in all axes (as mentioned above.)
    • Does not allow driver setup (microstep mode, current, etc.) at runtime without modification.
    • Tip: One big downside we notice are quality/design issues with some WeMos D1 R32's, apparently the 5V regulator can have problems.

  • The FYSETC S6
    • This is a good choice if you really want everything.  Just keep in mind that it's not modular and adding "everything" is still a very big project, one mistake and you might be buying another and going through what it takes to wire it all up again, so be careful.
    • Best with SPI StepStick TMC2130 or TMC5160 drivers in all axes.
    • Allows driver setup (microstep mode, current, etc.) at runtime for all axes.
    • Has built-in heater outputs (we use for dew-heaters.)

  • The RAMPS and MKS Gen-L
    • One of the first 3D printer boards was the RAMPS1.4 Shield for the Arduino Mega2560, this has some pretty big drawbacks but is workable.
    • The best of these designs is the all-in-one (Mega2560 and RAMPS on one board) MKS Gen-L v2.1, it supports the TMC2130 and TMC5160 SPI stepper drivers and has a crystal oscillator of accurate tracking.
    • Best with SPI StepStick TMC2130 or TMC5160 drivers in all axes.
    • Allows driver setup (microstep mode, current, etc.) at runtime for all axes.
    • Has built-in heater outputs (we use for dew-heaters.)
    • Tip: These boards all have performance limitations and are starting to become obsolete as the newest OnStepX has begun to exceed the primitive Mega2560 processors capabilities.