Just getting into this project after seeing an old HP-85 for sale. Thought I might be able to design a keyboard with a similar back panel containing a screen and some switches. Couldn’t find a good beige acrylic at my laser cutting place so I’ve gone for an Atari colour scheme of gloss black and dark wood.
This is my first go using laser cut flat parts to make a 3D design and I’m pretty happy with how it’s come out.
For reference the hole on the left of the back panel will house a 4 line LCD which I’ll use to report Caps Lock On, that sort of thing. I already have the display and it seems pretty simple to drive from my Teensy Arduino Board. The toggles on the right are labeled, just waiting on a momentary toggle for the page up/ page down switch as that one has to spring back to centre after being moved.
Switches-wise I’m intending to use Cherry MX black with 85g springs. Haven’t decided on keycaps yet, but something like PimpMyKeyboarf’s Grolsch is appealing.
Let me know what you think so far, or if you have any questions. Happy to go into any details.

Nice! But maybe one the large side for just a keyboard? 

Mine now has the LCD in and working, together with LEDs for Caps Lock and so on

I find that layout disturbing.
No Control key to the left of A, Delete key in a different spot, no right Alt key ...

How do you program the Insert toggle? AFAIK, USB does not even have a lock-light for that one and otherwise, USB does not have a defined relationship between light and key — it is the host that turns the lights on and off and sometimes a host doesn't.

I was talking about the keycap set. The photo was just to show a real Nuclear Data terminal and their keyboard/caps. The link in my post is to the page showing the Nuclear Data set from Signature Plastics.

Ahh I see! I got distracted by the awesome terminal! Yeah Nuclear looks nice actually, I like the really dark green they used. I could also be tempted by the Coffee set


I really want the caps they used on the old HP which had “End line” for the return key, can’t find a set like that though.

I monitor the status of insert, caps, scroll lock etc and set the LEDs myself. I appreciate that for Insert that probably can’t be done reliably, didn’t really think that through! But since I don’t use it much I figure it’ll mostly be ok

BTW. TMK supports latching lock keys (and I suppose forks like QMK do too) by sending fake key presses if the light changes to something else than internal state. But as I said, it does not always work in all circumstances.
I remember in an older version of Linux when I had two keyboards plugged in and pressed Num Lock on one, the light changed only on that keyboard even though the interpretation of the numpad changed for keys from all plugged-in keyboards.

Thought I'd add some images of the final keyboard.
I'm really happy with how the chassis turned out, the piano black with the wood panels looks really 80's Atari style.
The only mistake was the insert key, which I had to change to be a non-latching toggle because it doesn't behave like caps lock and scroll lock. So now that switch springs back to center after you press it, effectively behaving like any other key switch.
Maybe if I did it again I'd add a headphone jack too, because that'd definitely fit in. But overall, my best keyboard yet, now onto the next one!

love the "not quite standard" layout. definitely lends itself to the period/theme you are shooting for.

photo courtesy of: https://geekhack.org/index.php?topic=46957.msg1070610#msg1070610

for caps...
for the look your going for, shuold be spherical/high profile, should be large centerd legends for the alpha numeric, preferably a lighter color keycap. black or dark would blend into the case.

alps skcc are still a viable option and have probably the widest variety of vintage sphericals more readily available then vintage mx sphericals (i could be wrong though)
skcc should fit in mx plate
https://deskthority.net/wiki/Alps_keyboard_codes
- Alps AKB-3420
- Some Radio Shack TRS-80 Model I (1979)
- Some Radio Shack TRS-80 Model III[2]
- Some Texas Instruments TI-99/4A
- Apple m0110, Apple m0110a, Apple m0120 (tall cream)
- IBM 6113442 (green)
- IBM 5954339 (green)

you could do commodore 64 caps w/adapters for mx switches
https://www.breadbox64.com/blog/c64-keyboard-prototype/

other than that.... find a new SA set you like & run with it.

Just getting into this project after seeing an old HP-85 for sale. Thought I might be able to design a keyboard with a similar back panel containing a screen and some switches. Couldn’t find a good beige acrylic at my laser cutting place so I’ve gone for an Atari colour scheme of gloss black and dark wood.
This is my first go using laser cut flat parts to make a 3D design and I’m pretty happy with how it’s come out.
For reference the hole on the left of the back panel will house a 4 line LCD which I’ll use to report Caps Lock On, that sort of thing. I already have the display and it seems pretty simple to drive from my Teensy Arduino Board. The toggles on the right are labeled, just waiting on a momentary toggle for the page up/ page down switch as that one has to spring back to centre after being moved.
Switches-wise I’m intending to use Cherry MX black with 85g springs. Haven’t decided on keycaps yet, but something like PimpMyKeyboarf’s Grolsch is appealing.
Let me know what you think so far, or if you have any questions. Happy to go into any details.
(Attachment Link)

Amazing! I reccomend you get a set that looks like the old honeywell keyboards.

Amazing work.

I'd like to see what a MT3 profile keycap set looked like on that.