Vintage Computer FestivalVCF West 2026on the exhibit table
One builder · one 1981 computer · a decade of rebuilding it in hardware

TEN YEARS OF
MICROTRONIC EMULATORS

Some people build ships in bottles. Over 2016–2026, Michael Wessel rebuilt the 1981 Busch Microtronic in hardware — a family of Arduino-based emulators, from the first Mega 2560 to the Phoenix that runs the original 1981 firmware ROM — winning two international retro-computing prizes along the way.
★ Hackaday “Reinvented Retro” Contest 2021 — winner (the Next-Generation Nokia-LCD build), and featured on the Hackaday front page.
★ RetroChallenge 2021/10 — prize winner: a MIDI drum computer written in Microtronic machine code on the Retro-Authentic Bubble-LED Microtronic.

01THE JOURNEY — A DECADE OF BUILDS

Mega 2560
2016 · the original
A whole Microtronic in an Arduino Mega + LCD, with Emic-2 speech synthesis. Where the road began.
Next Generation · Nokia LCD
2019–21 · prize winner
Custom PCB: live-disassembler LCD, SD-card storage, 2095 cassette emulation, RTC, sound, DIN/DOT I/O.
★ Hackaday front page + Reinvented Retro 2021 winner
Next Generation · OLED
2021+ · the refinement
The same design with a crisp 1.3″ SH1106 OLED — big-font, register and disassembler display modes.
2nd Generation
2020 · sister build
By Frank de Jaeger & Manfred Henf: same firmware, a 3D-printed keypad into a real Busch console, transistor-accurate I/O.
Retro-Authentic Bubble-LED
2021
A TI/TMS bubble-LED display for true 1981 authenticity; host to a MIDI drum computer written in Microtronic machine code.
★ RetroChallenge 2021/10 winner
Phoenix
2025 · the finale
Runs the actual 1981 firmware ROM on new hardware — with Jason T. Jacques & Decle.
★ Hackster & Hackaday featured

02THE ARC — FROM EMULATING BEHAVIOUR TO RUNNING THE REAL ROM

For most of the journey the emulators reproduced the Microtronic’s behaviour, worked out from its manuals — the 1981 firmware was mask-programmed inside the TI TMS1600 chip and had never been dumped. The finale changed that: together with Jason T. Jacques and Decle, the original ROM was finally extracted and disassembled, and the Phoenix now executes the genuine 1981 firmware on a cycle-accurate TMS1600 emulator (alongside Michael’s own Arduino “Neo” re-implementation). The real machine’s soul, reborn on new silicon.

2016 Mega 2560 → 2019 Next-Gen LCD → 2020 2nd Gen → 2021 Bubble-LED + OLED → 2025  PHOENIX — the original ROM lives again

03PRESS & PRIZES

  • Hackaday “Reinvented Retro” Contest 2021 — winner (Next Generation), and front-paged on Hackaday.
  • RetroChallenge 2021/10 — prize winner: the Bubble-LED Microtronic MIDI drum computer.
  • Hackster.io — “The Four-Bit Busch Microtronic Lives Again as the Microtronic Phoenix — Complete with Original ROM.”
  • Hackaday — the Phoenix and the “firmware-ROM archaeology” project, featured.
  • LOAD #11 (Oct 2025) — Germany’s VzEkC “classic computing” magazine covered the Microtronic and its emulators.
  • Grew from 1 to 6 contributors over ten years; full build videos on YouTube.
Hackster.io — the Phoenix
RetroChallenge 2021/10 — “Prize Winner”
All builds, firmware & Gerbers
Sketches, PCBs and docs for every emulator generation.
github.com/lambdamikel/Busch-2090