Microtronic - The Next Generation

What a nice surprise! We are among the lucky winners of the REINVENTED RETRO CONTEST - what an honor to be selected from the pool of 138 amazing contenders!

https://hackaday.com/2021/07/17/reinvented-retro-contest-winners-announced/

Thanks  so much to the Hackaday organizers, judges and community for the votes!!

Whereas I started a first version of this project in 2016, this project would not have reached its current level of maturity and form factor without the "Microtronic Second Generation" Sister Project and my team members Frank de Jaeger, Manfred Henf, and Lilly. So I am gratefully accepting the prize for this extended team.

It was Frank who made me resurrect the project in 2020, suggested to use the Nokia 5110 display, and shrink down the form factor by switching from the Arduino Mega 2560 R3 used in my 2016 version to the Mega MiniPro 2560 board, resulting in a much more compact setup. Manfred did the 3d design and printing of the Second Generation case parts that nicely integrates into an original Busch console, and Lilly did a great job in quality control (testing, bug finding, ...) and significantly contributed to the firmware of yet another Microtronic sister project, the Retro-Authentic Bubble LED version: 

https://hackaday.io/project/180252-a-retro-authentic-microtronic-emulator

More info about the "Microtronic Second Generation" sister project (which was mainly driven by Frank and Manfred), and the "Retro-Authentic Bubble LED Display Microtronic" sister project below. THANKS TO ALL OF YOU!

https://www.rigert.com/ee-forum/viewtopic.php?t=2497

https://hackaday.io/project/180252-a-retro-authentic-microtronic-emulator

Here is a new take on this project - more retro-authentic than ever! Who needs displays if one can have a 6digit 7segment LED bubble display, like its 1981??
https://hackaday.io/project/180252-a-retro-authentic-microtronic-emulator

I added pulldown resistors to the digitial inputs to have higher electrical compatibility with the original Microtronic; i.e., electronics experiments as decribed in the Busch manual require non-inverted logic (I was using the internal pullups previously). Ideally, I should have added transistor drivers or at least 2 74LS243 4bit bus transceivers (one for input DIN, one for output DOT). Anyhow, the experiments from the manuals I tried so far all worked; none of them sources or sinks a lot of current into the GPIOs.

Also, mirror holders from ACE Hardware make a great set of PCB feet! The PCB is final now - OK, a battery holder would be nice... anyhow, there is always something that needs improvement with these projects, and sometimes, good enough must be good enough ;-) I consider the project done by now.

Trying an official experiment from the Microtronic manual to check compatibility of the output ports with Busch electronics experiments / circuits as described in the Microtronic manual. I had the output ports inverted previously - with that being fixed in the firmware, the experiment conducted here demonstrates principles of "data transmission". The Microtronic Next Generation is driving a CLOCK and a RESET line into a Busch 2075 Counter Module, and a (decimal) digit is being transmitted from the Next Generation to the Counter Module. With the corrected firmware (non-inverted outputs) it works fine.

The OshPark PCBs work flawlessly! Functionality is identical to the Nokia 5110 version. Note that I am running from battery this time!

I also made another video: 

Just got note from OshPark that my 2nd PCB batch is on the way: I swapped the Nokia 5110 with an SH-1106 SPI OLED display. The SH-1106 SPI was selected after a number of experiments that I conducted in order to identify the fastest monochrome display for the project. The Nokia is nice, but a little bit too laggy; it gets too blurry if refreshed fastly. The SPI SH-1106 doesn't have that issue and is crystal sharp as well as a bit faster than the Nokia: