Pro 3.0 build with a few tweaks

[Marco]

HI all,

I have just finished my Pro 3.0 build, which was a very pleasant build from a to z. Only broke off one switch (and I didn't even tighten the nut a lot at all) build could fix it with a spare I had lying around and the inners of the broken toggle switch. Always trying to build as solid as I can, I made the following tweaks to the build:

• On first assembly of the front panel I found it to be flexing to much and the switches and LED's not protruding equally. I ended up with adding extra spacers (the blue 3D printed parts here) to the aluminium frame which involved drilling extra holes.
• I had to enlarge the six holes in the aluminium frame a bit for the switches and LED's to eventually align properly with the front panel.
• The extra wires on the PCB are for the ESP-10s reset and external LED (three wires going to an extra connector on the other side of the PCB), and the other two are a repair after I foolishly thought I could get away with removing the soldered on SD card reader without disassembling the front panel first, resulting in two broken traces. And then people say you learn from your previous mistakes. Apparently not...
  

• I did the RX/TX mod on the Arduino, because it is the best solution without sacrificing other connections. I have added a small connector to the Arduino for this, 30awg wirewrap wire is great for soldering on SMD parts but net very robust, thats why I have added the connector and use thicker flexible wire to the PCB connectors.
• Moved the SD card module to the rear of the case, replaced on the PCB by a simple pin connectors.
  
• The other new connector on the main PCB is for the ESP-10s reset and external LED.

• Used extra connectors on the second PCB, for easier disassembly.
• Added a fan. It's a 12V fan running on 5V, obviously, so it's just for effect. Maybe I will add a switch to turn it on and off at my digression. And I don't know why it uses a 3-pin connector as the third connection (tachometer) is not connected on the PCB, so a simpler 2 wire fan would have worked just as well.
• Added covers for the left slots at the rear of the case. Two blanks and two are populated. The top is the moved SD card reader. This works just as if it were still mounted on the main PCB, just easier accessible. I actually damaged it whilst removing it from the PCB were I had initially soldered in on as per the instructions, but was able to repair the damaged traces. Not an expensive item and I actually already had a spare, but it is more fun to fix the damaged part (specially if broken by own stupidity).
• The other cover houses a reset button for the ESP-10s (which I quickly found I needed) and a LED connected to the GPIO2 pin on the SP. Because the on onboard LED is actually on when the pin is LOW (typical ESP behavior) and I only want the external LED to light when the ESP is resetting, I altered the HIGH and LOW statements in the sketch before flashing the ESP.
  

Now, let's have some fun with it, and see if I can find it to do something useful (relatively speaking, of course).

Marco

[Chris Davis]

Very awesome tweaks!  I especially like the spacers for the front panel.  I don't know why you had to adjust the size of the holes in the aluminum frame, they were supposed to align perfectly.  I have run across one other front panel that did not align correctly, so maybe you got the second.  I'm glad you were able to make it fit.

Why the three-pin fan connector?  Because that's what I had in my shop!

[Marco]

>>> I don't know why you had to adjust the size of the holes in the aluminum frame, they were supposed to align perfectly.  I have run across one other front panel that did not align correctly, so maybe you got the second.  I'm glad you were able to make it fit.

I'm probably just fussy about half a millimeter, but I didn't want to use any force when I couldn't fit the front panel on the first try.

>>> Why the three-pin fan connector?  Because that's what I had in my shop!

I figured so :-D

Thanks for a great kit!

Op maandag 5 mei 2025 om 16:44:17 UTC+2 schreef famousd...@gmail.com:

[Marco]

>>> I decided to keep the SD where it was because I've seen to many issues with bad contacts and also interference with having long wires to relocate the SD to the back of the machine.

I have had mixed results with those SD card extenders you just insert into an existing card reader. Some work well, some don't or at best sometimes. Therefore I opted to just put the card reader itself at te  rear and lengten the connection, I was still worried about interference but (in this case at least) tests have shown these are unprofound.

Op maandag 5 mei 2025 om 16:47:59 UTC+2 schreef John Galt:

its amazing how fast you fill up the back panel. i have extra serial ports, internal I/O boards that needed external connections. 3d printed 9pin and DIN adapters. i even managed to fill the 2 round ports with various data and audio connections.

had to stop myself from cutting more ports in the back of the case so i ended up running multiple ribbon cables that exit over the top lip of the rear of the case and exit between the rear panel and the case top.

I ran out of room I can't even load anymore i/o boards in the machine LOL. 

I decided to keep the SD where it was because I've seen to many issues with bad contacts and also interference with having long wires to relocate the SD to the back of the machine. 

It causes a bit of an issue with changing out Hard drive images. But I added a bunch of extra blank images before I sealed the case. Plus i'm well beyond the Shipped 4gb SD hee hee 

 I have external floppies, plus i added internal blanks. much more then anyone would of had back in the day

cable management is still a nightmare no matter how much you try and organize the chaos.

[Walt Perko]

Hi, 

I've tried several µSD extension cables ... they just don't seem to work.  That's my only complaint about the hardware for a replica computer, the µSD card slot couldn't be on the front panel.  

I wish somebody could write a Floppy Serial Drive Server like program for the Altair-Duino Pro's ... That would make using the computer easier and more fun.  

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[Tom Wilson]

Someone did. It’s on the group… there’s a server you run on your PC, and you have to run a custom CP/M OS to mount drives over serial. 

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[Walt Perko]

Hi, 

The ESP32 WiFi works with the Altair-Duino Pro?   or is it a Serial CP/M?  

I didn't think these would work with the Altair-Duino Pro since they're aimed at the Altair 8800 computers.  

.

[Patrick Linstruth]

It’s on my to do list to try and add Mike Douglas’ Serial Driver Server protocol to the Altair-Duino. I too am not a fan of sd card media, especially with the card in the rear.

I imagine Mike's Serial CP/M would work without any changes.

On May 6, 2025, at 2:25 PM, Marco <crou...@gmail.com> wrote:

There is provision for an esp-01s as a serial device, so you get a telnet connection over WiFi to the Altair-Duino. I suppose with some tweaking you could use any kind of ESP32 , I actually was contemplating using a NodeMCU, which I am quite familiar with and have a whole bunch around waiting to be used in one project or another. But the esp-01 just works so no real benefit in using a NodeMCU, besides more GPIO ports for more blinking LEDs...

Op dinsdag 6 mei 2025 om 06:56:40 UTC+2 schreef r4r...@gmail.com:

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/fc5fb2e1-577b-45b3-b7fe-b2e94992e33en%40googlegroups.com.

[Walt Perko]

Hi, 

The only reason I haven't tried Mike's Serial CP/M is that it requires 57.6K BAUD speed and the Altair-Duino Pro (A6/A7) only goes up to 19.2K  BAUD.  

Now 19.2K BAUD might be an okay speed considering the improved versatility of the computer overall but it's designed for the 88-2SIO address 18d/19d ... not A6/a7 ... 

IF somebody knows how to setup the Altair-Duino Pro computer so I can have a serial port on address 18d/19 (12h/13h) I could give it a try.  The Altair-Duino Pro I have does not have the external expansion buss.  

All I can figure is that Mike's Serial CP/M might need to be configured to use A6/A7 port maybe call it the A6Serial CP/M?  

.

[Patrick Linstruth]

The first thing on my list was to figure to what serial data rate the Altair-Duino would support. If it wasn’t at least 57.6K, I wasn’t going to bother with the serial server.

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/19096ca1-526f-4921-b90f-99cb7905f5c8n%40googlegroups.com.

[Walt Perko]

Hi, 

Yeah, 19.2K BAUD seems slow, but the Serial Drive Server software on my PC say's it can go down to 9600 BAUD!  

I think even 9600 BAUD is useful, but I would rather run at 19.2K BAUD since the Altair-Duino Pro A6/A7 port can support that speed.  

.

[Walt Perko]

Hi, 

The issue is reliability.  It seems 19.2K BAUD has good reliability to pass data back 'n forth.  

The nice thing is, once BOOTed to CP/M (probably would take the longest time of all operations), then loading and running programs shouldn't be as much of a wait other than loading MBASIC or DZMBASIC first.  

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[Marco]

A week and a bit later, time for a little update on my build.

• I removed the SD card extension again, after all. I always knew it would be tricky but it did work well the first couple of days. But as these things always seem to go, the wind turned outside or something like that, and suddenly there were problems with the SD card. So the SC card reader is back on on the main PCB. I had to try... At least it frees up a slot on the back plane!
• The esp reset button and LED were moved to the two holes under the back plane slots, I don't think I will ever be using these for a cassette interface or whatever.
• Made the LED output register board and figured it wasn't much fun to have the LEDs blinking inside the case. So I extended the LED pins to a new DB9 connector, and 3D printed a little LED box, just for fun:

Config 0 is now set to the esp-01s, which means I can just power on the Altair and connect with my VT-100 terminal replica with a single key press and without the need for any switches.

Op woensdag 7 mei 2025 om 04:07:21 UTC+2 schreef r4r...@gmail.com:

[Walt Perko]

Hi, 

Wow, that's a really nice looking setup!  Good Job!  

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