I just wanted to share a preview of a open source mod I’ve been working on. My design goals were:

  • 0.05g accuracy
  • Single-shot self-learning algorithm (no need for tuning, even after changing beans or grind settings)
  • Professional appearance
  • User-friendly operation
  • No permanent modifications to the grinder

Costs are roughly about 40-50 eur.

I’ve iterated on this design, testing various control algorithms and different hardware (ADC converters, load cells, boards, etc.). I’m very happy with the current result. It consistently grinds on target, and if – on the rare occasion – the last pulse triggers an avalanche of grinds and causes an overshoot, at least you’ll know. 🙂

The endgoal is to share the design as an open source project.



by Jaappppppp

28 Comments

  1. danimal1986

    Wow thats pretty awesome!

    Pretty cool if you already had a specialita and wanted to have the GBW like the libra.

  2. ruesselmann

    I love you man – if that works let me get you a coffee

  3. morpheus1988wer

    Which eureka grinders will be compatible with? Would a Silenzio work?

  4. Miserable_Potato283

    I’m in, do you have a GitHub? I have this same grinder and have done a single dose modification which I’ll happily remove.

  5. Mountain_Comparison8

    How easy/difficult is the mod? This is brilliant!

  6. tomrutgers

    Highly interested in this as I have two specialitas. No 3D printer or soldering skills though

  7. classicsalamitactics

    Great work! Have done a similar mod myself, using an external display however. How have you been able to use the original touch display?

  8. klimbo731

    Oh my god!!!
    What a beast!!! That’s insane!!! My Specialità is dying to try that out!!! Hahaha

  9. Radiant-Seaweed-4800

    There is already an openGBW on github, and I finished it about a week ago.
    It works great.

    Instead of doing little spurts like yours does, this one tries to calculate the amount that will come out after stopping.
    It usually hits within 0.1g, when switching beans the worst I saw was 0.3 out.

    Uses an ESP32, a load cell, screen, rotary encoder and some 3D prints.
    I had to modify the code a little to make it work, but know that it does work I’l never go back to single dosing.

    Here’s the link:
    https://github.com/jb-xyz/openGBW

  10. Aggressive_Peach_768

    On a side note, how does the specialita compares to the encore ESP Pro?

  11. Just… making sure… you all know they make a “gbw specialita” already called Libra, right?

  12. hukkaberry

    Seems like something a lot of people would pay $10-50 for.

  13. ziptiefighter

    Good thing I have a Mignon Zero (plain old delightfully dumb On/Off toggle switch) or I’d be tempted.

    Nicely done!

  14. Downtown_Look_5597

    Could you make this without the Specialita’s screen? Maybe using an android app for the interface. Asking for a crono owner 😀

  15. drewjustdgaf

    Can I get this for my Libra? That updated display would be a nice touch.

  16. Cool! I’m interested to try it out, if you’re open to share it. I am a dev and electronics fan so if you have a repo that’d be great 😇

  17. palonewabone

    So many particulates flying around. Do you even spritz your beans?
    What? this isn’t r/espressocirclejerk ? My bad.