MC6205/MS6205 | ESP32 Weatherstation, NTP Clock

Details

This is my first project to make public. I love neon filled tubes, because of their warm glow.
Sure, I've already build some clocks using nixie tubes, but this russian 1990´s MC6205 is very special and it catches my interest.
The MC6205 uses a IGPP-100/100 (GIP-10000), which is a 10000 pixel plasma tube. Technically similar to Burroughs SelfScan Plasma tubes.
It has been used in USSR CNC systems, programmable logic controllers and bill counters.

Unfortunately, after I powered it up the first time, I realized, that it has only a limited set of 96 characters. Most in cyrillic and that rendered it nearly unusable for me.
But hey, in the package, there was the solution for it. Some very detailed schematics.
It took some time, to re-engineer the used eprom's character-set definitions, which was/is really weird.
So, what you will find in this project is a MC6205, which works with an expanded set of 128 characters based on western ISO-Latin-1 and connection to the internet via WLAN.

Obstacles:
- main obstacle, you need a customized ROM (EEPROM 2816 or EPROM 2716, 2732)
- further you need soldering experience, a PCB with the driver logic and an e(e)prommer, or ask me for the PCB/PROM

What you get:
- Some really nice days of hardware and software hacking
- a functional basic weatherstation (based on data from openweathermap.org - get your API key from there)
- NTP-clock
- Terminal, where you can display your text via the internet
- ESP32 Arduino knowhow

Power consumption:
Using a standard 12V 1A wall mount powersupply and usage of the MP2307 the average power consumption is about 90mA.

Hardware modification:

How does the hardware change work to get the missing data bit and the advanced charset:

This is the picture of the original charset with no hardware change. Look at Bit 6 und 7 (arrows

And the picture with the changed hardware:

So, what make the difference to see the hidden charset this time.
Let's take a look at the schematics:

The point of interest is gate D7.2, an AND gate (к155ли1==7408). As you can see, trace 6 and 7 are connected to pin 12 and 13, the inputs of the AND gate. Trace 6 and 7 corresponds to bit 6 (18B) and 7 (24B).

With trial and error plus schematics and knowledge of the ROM's data this leads to success. Cutting the output of the AND gate and connecting the open trace to A8 (20A) gave me the missing characters.
But in fact it is a modified trigger of the WR mimic to the onboard RAM. Just follow the green trace and the ouput traces of the corresponding gates. (Full schematics in the files section)
Please keep in mind, that the data and address bus are connected together via the driver PCB.

But why did the hardware designer do that, mystique...

So, if you have a different schematics, layout, then look at those bits and the corresponding AND/NAND gates.

Files

MS6205_HW_Test_V1.0.zip

Arduino & VS Code (platformio) code to test the MC6205

Zip Archive - 11.92 kB - 05/07/2021 at 21:54

Download

Custom_PROM.mp4

Video of running the testprogram with the customized PROM and after hardware change. (Described in the project)

MPEG-4 Video - 21.44 MB - 05/07/2021 at 21:43

Download

Original_PROM.mp4

Video of running the testprogram with original PROM but after hardware change. (Described in the project)

MPEG-4 Video - 21.07 MB - 05/07/2021 at 21:41

Download

MC6205_Driver_PCB-V1.1-Horizon.zip

Driver PCB with ESP32-WROOM (Eagle format) you do "not" need a СНО63-48 connector

Zip Archive - 174.48 kB - 05/07/2021 at 17:56

Download

EPROM_ISO.bin

the ISO-Latin1 e(e)prom data. MD5: e4b68f60f8ba3c8036d98be958cd3137

macbinary - 2.00 kB - 04/26/2021 at 15:27

Download

Components

1 × Connector СНО63-48 (optional) MC6205 connector

1 × ESP-WROOM-32 ESP32 DEVKITV1

1 × MP2307 module step down converter (fixed to 5V)

1 × 74HC595 Electronic Components / Misc. Electronic Components

1 × PCB the driver PCB

Project Logs

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github

jörg postert • 05/16/2021 at 22:46 • 0 comments

Published the sourcecode on github.

https://github.com/jopo64/MC6205

Connector removal

jörg postert • 05/09/2021 at 07:51 • 0 comments

If you are planning to use the all-internal version, here is the „how-to-not-to-do“ way to remove the connector. ;)

If you don‘t want to preserve it, then it is a way...

Easteregg

jörg postert • 05/08/2021 at 20:41 • 1 comment

There is a hidden set of characters in the original PROM. It was pretty funny to discover it.

Height reduction

jörg postert • 05/08/2021 at 20:30 • 0 comments

Be carefull, if you reduce the spacer of the display board to the tube board. Attention not to break the glass-seal.

Testsoftware

jörg postert • 05/07/2021 at 21:59 • 0 comments

First publish of testsoftware for the MC6205 on Arduino.
The Zip is in the files section.

MC6205 boxed

jörg postert • 05/07/2021 at 17:44 • 0 comments

Just a short update:
A new set of PCB's V1.1-H arrived. This time I had included all parts in the original metallcase.
PCB (Eagle format) and Gerber attached in files section.
Have fun.

I'm very satisfied with that look.

PCB's V1.1

jörg postert • 04/27/2021 at 08:35 • 0 comments

The PCB's (V1.1-V) arrived. I've assembled it and it is working flawless.

Driver PCB version 1.1-V

jörg postert • 04/13/2021 at 20:36 • 0 comments

Created new version of the PCB for connecting the ESP32 to the MC6205
Schematics and Gerber attached in the files section.

This PCB can be self-etched (traces are pretty wide) and yes, it's double sided.

I've ordered a small batch (5).

Build Instructions

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Step 1

The MC6205 bottom PCB must be changed to support the additional 'faked' data bit.
Please check your MC6205 schematics against my published one, because they could be slightly different, same for the PCB.

Step 2

Driver PCB: (Attention)

If you plan to use the MP2307 step-down converter module to provide the 5V for the logic components and Arduino, you have to trim it with the onboard potentiometer. So before you solder it on the PCB, please set it up to 5V !

Step 3

Run your code to display the standard character set (original EPROM) but with advanced character range.
Be surprised...

Discussions

jondaddio wrote 05/08/2021 at 23:40

Fantastic project !!

Are you sure? yes | no

jondaddio wrote 05/08/2021 at 16:58

Is the external antenna on the ESP-WROOM-32 board really needed (ESP-WROOM-32U)? I see a few boards for sale with that external antenna connector, but is it needed for the metal case with the holes in it ??

Are you sure? yes | no

jörg postert wrote 05/08/2021 at 20:14

An external antenna must not be used. My home WLAN is a bit weak, so I solderd the antenna based ESP32 on it. And an external antenna outside the case could look nice. Anyway, it‘s only an option.

Are you sure? yes | no

jondaddio wrote 05/08/2021 at 22:14

Thanks for the reply !!

Are you sure? yes | no

jörg postert wrote 05/07/2021 at 22:07

If someone want to get the PCB's and/or EEPROM, feel free to ask.

Are you sure? yes | no

sig freud wrote 05/07/2021 at 12:59

Would love the info about the programmer too :)

Are you sure? yes | no

jörg postert wrote 05/17/2021 at 10:04

Please take a look at https://hackaday.io/project/171757-eeprom-programmer
This is pretty the same way I did. But with GUI. Should be pretty simple to adopt to the smaller X2816.

Are you sure? yes | no

Lucy Fauth wrote 04/24/2021 at 23:29

Hi! This is amazing work!

I have the same display and would like to replace / reprogram the EEPROM. Can you go into detail how you did that, what part / programmer you used and share the binary you ended up flashing?

Thanks!

Are you sure? yes | no

jörg postert wrote 05/08/2021 at 20:17

Hi, thank you. The programmer is a DIY one using an old Arduino UNO with python code. The old EPROM must be removed and a 24-pin socket soldered in. It is a bit tricky, to remove the PROM. But a good solder-iron, or hot-air station will do the work. If it don't mind, the PROM could be removed with a wire cable cutter.

Are you sure? yes | no

jondaddio wrote 05/08/2021 at 23:45

I also will have the same display (ordered today, so I'll have it in a month-and-a-half or so) and would like details on the EPROM replacement. Are there photos of this old EPROM (was that the black device I saw)? I looked through the photos and did not obviously see it. Though you did post the schematic. Great project !!

Are you sure? yes | no

MC6205/MS6205 | ESP32 Weatherstation, NTP Clock

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