Lmst

As it's an #OctopusEnergy saving hour, seems the perfect time to fire up the #zx81 clone laptop from battery. A more elegant design you simply couldn't make 😂😂
#retrocomputing #retrogaming
#zx81plus38

Finished the #Sinclair #ZX81plus38. An explanation that I found for myself for the name, the project was started 38 years after the original? But that's just guesswork.
I actually forgot one soldering point at ground on a TTL 😆 Now it's running rock stable and I left it at 16k RAM. I chose one of the nicer cases, actually like new, for it. It also got a keyboard with that little clicky tactile switches.
#RetroComputing #ZilogZ80

#ZX81 issue one circuit board compared the the ZX81+38 NoULA board

First test after I found the missing solder point ;)

@swetland Well done, congratulations! The typing experience must be unprecedented for a ZX81, I suppose. When I assembled a #zx81plus38 board some time ago, I decided to go for a more budget-friendly type of homebrew keyboard.

https://www.hackup.net/2022/01/building-a-new-zx81-computer/
https://github.com/hackup/ZX81TactileKeyboard

Homebrew PCB for a ZX81 with tactile switches installed.

Motherboard, keyboard, and case components for the ZX81+38.

The finished ZX81+38 project with homebrew keyboard and 3D printed case.

"A mechanical keyboard that's compatible with the Sinclair ZX81, as well as the ZX81+38 modern recreation of that machine. This repository contains all the design files as well as various exported versions and images."

ZX81 Mechanical Keyboard - https://github.com/swetland/zx81-keyboard

#zx81 #zx81plus38

The ZX81 case I built is starting to look real nice!
#zx81 #zx81plus38 #retrocomputing

Happy Valentine’s Day. ZX81 clone love ❤️ #zx81 #zx81plus38 #MechanicalKeyboard

Hoo boy, it has been a while since I did any woodworking. First steps show some promise, though!
#zx81 #zx81plus38 #woodworking

The beginnings of a wood case for my ZX81 clone

Just whipped up a proper keyboard for my ZX81 clone! It's much nicer than the tact switch one I had been using. It was also really helpful to have the key labels designed by @iNimbleSloth !
#zx81 #zx81plus38 #customkeyboards

A repeating BASIC program extolling my success

Blowing off some after-work steam building a mechanical keyboard for my ZX81 clone
#zx81
#zx81plus38

Mechanical keyboard for ZX81 clone in progress

@arturo182 some additional fun photos...
#Projects #ZX81plus38 #zx81 #2022

An array of DIP ICs in anti-static tubes on my kitchen counter, mostly 74HCTxx series.

Unpopulated PCBs for the ZX81+38 and mechanical keyboard sitting in an orange 3d printed enclosure bottom half.

Close-up of a tall zero-insertation-force socket to regular DIP socket adapter plugged into the ZX81+38 to allow for quick swapping of the system EEPROM.

Custom keycaps design for the ZX81+38 mechanical keyboard. Each key includes (color coded) BASIC keywords, functions, and/or symbols.

@arturo182 I built up a ZX81+38 from MAHJONGG's PCB design (Modern recreation of the ZX81 using discrete 74xx chips instead of ULA), and created a custom mechanical keyboard, custom keycaps, and enclosure for it. An IO expansion and ROM customization are still ongoing projects.
#Projects #ZX81plus38 #zx81 #2022

ZX81 mainboard and keyboard in 3d printed case bottom half (orange). Temporary (non-custom) keycaps on the mechanical keys.

ZX81+38 mainboard and mechanical keyboard (now with custom printed keycaps) in 3d printed enclosure (now with cover plate over keyboard).

Tascam handheld digital audio recorder being used to load a program on to the ZX81+38 via the tape interface.

ZX81+38 display (via scan converter on a Dell 1080p monitor) showing the listing of a BASIC program that plots a sine wave.

@swetland I built a #zx81plus38 just a few months ago! Very rewarding to get it up and running. Can't wait to dig into your blog and read about that handsome case and mechanical keyboard!

For those who are new here and didn't see these posts (or similar on my twitter), over the summer I spent some time building a ZX81+38 (modern reproduction of the Sinclair ZX81 using discrete logic instead of the ULA chip).

You can see all those posts here:
https://chaos.social/@swetland/tagged/zx81

#zx81 #zx81plus38 #projects #retrocomputing

Tubes of 7400 series DIP ICs on the kitchen counter.

zx81+38 loading programs from a TASCAM handheld audio recorder.

zx81+38 mainboard standing on end in case, oscilloscope probes attached, IO board plugged in, and bench power supply in the background.

zx81+38 in orange 3D printed case, no cover over the mainboard, custom keycaps installed on the mechanical keyboard.

Happily installed in the ZX81+38...

#hw #projects #zx81 #zx81plus38

The v2 zx-pico-io boards arrived and apart from me failing to fix the level shifter footprint (non-fatal, just annoying to solder with this spacing), everything else is looking good after moving z80 and pico software to use IO ports instead of memory mapped IO.

#zx81 #zx81plus38 #zx-pico-io #hw #projects

After much hacking on the v1.1 PCBs I finally have a design for the v2.0 ZX-PICO-IO boards going out to fab. Featuring right-side-up connectors, IOPORT rather than MEMORY interface, PICO controlled nRESET and other improvements...
#zx81 #zx81plus38 #hw #projects #pcb

Not going to win any awards for this soldering. To be fair some idiot used the wrong (too wide) footprints for the level shifters. To be fair that idiot was me. But with the headers inverted the ZX81 continues to operate with the board present. Now to write some firmware.

#zx81 #zx81plus38 #hw #projects #zx-pico-io

With the connector inverted the signals go to the right places (yay) but things are a little awkward. Still, the address decoder seems happy, so on to the level shifters and then the RPI Pico and then we see if we can make this all talk.

#zx81 #zx81plus38 #hw #projects #zx-pico-io

#ZX81plus38

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