User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Fri Jun 02, 2023 2:11 pm

mahjongg wrote:
Sun May 28, 2023 12:16 pm
I have been asked to explain more about the jumpers on the ZX81+38, note that no jumpers need to be touched, they are all already set (with a copper trace) to default settings. But curious people want to know. Okay Ill write a document explaining all jumpers and what they do.
Us usual I will publish it on GitHub. (by the way, the schematic also explains all jumpers.
I have written the document, and released it on GitHub.

User avatar
swetland
Posts: 29
Joined: Mon Feb 01, 2021 6:02 pm
Location: Palo Alto, CA

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Tue Jun 13, 2023 10:28 pm

I finally got around to tidying up all my design files for the PCB and keycaps for the mechanical keyboard I built to use with the ZX81+38.

They're all available on github now: https://github.com/swetland/zx81-keyboard

I added some ZX81+38 links so that anyone stumbling over the keyboard and in need of a computer for it might more easily find out about it.

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Wed Jun 14, 2023 4:44 pm

swetland wrote:
Tue Jun 13, 2023 10:28 pm
I finally got around to tidying up all my design files for the PCB and keycaps for the mechanical keyboard I built to use with the ZX81+38.

They're all available on github now: https://github.com/swetland/zx81-keyboard

I added some ZX81+38 links so that anyone stumbling over the keyboard and in need of a computer for it might more easily find out about it.
thanks swetland.

Actually I have decoded that so many people want a better keyboard that I will design my own version, using high quality SPST keyboard buttons, similar (or maybe even the same) as your, so maybe ALPs buttons, I'm still investigating the matter.
The main reason I want to design my own is that I want the left side of the keyboard to align with the left side of my ZX81+38, while the flat cable wires should lign up with the locations of the keyboard connectors too. I also want my keyboard to have a power on LED.
Maybe you think my effort is unnecessary but I simply wan't an "official" large keyboard. I already assigned a halfway decent keyboard for my rhococo color computer (prototype, it is not ready yet) you can also find this on my GitHub page, its of the same type as the 6 x 6 mm buttons, but twice as large, and it also has flat square keycaps for it. So I built that keyboard, but I myst say the quality is lacking.
So no I don't want the "buckling spring" keyboards that IBM was using for they PC's, those are probably overkill, but I do want a nice keyboard.
at least as good as or better than most home computers used.
Thanks for showing that it IS possible to put good lettering on the keycaps.
by the way there is a YouTube that also built my ZX81+38, and he also designed his own large keyboard.

see it here: https://www.youtube.com/watch?v=c1G5rX_YvCA

User avatar
swetland
Posts: 29
Joined: Mon Feb 01, 2021 6:02 pm
Location: Palo Alto, CA

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Wed Jun 14, 2023 9:07 pm

mahjongg wrote:
Wed Jun 14, 2023 4:44 pm
Actually I have decoded that so many people want a better keyboard that I will design my own version, using high quality SPST keyboard buttons, similar (or maybe even the same) as your, so maybe ALPs buttons, I'm still investigating the matter.
The main reason I want to design my own is that I want the left side of the keyboard to align with the left side of my ZX81+38, while the flat cable wires should lign up with the locations of the keyboard connectors too. I also want my keyboard to have a power on LED.
Maybe you think my effort is unnecessary but I simply wan't an "official" large keyboard.
It makes perfect sense to me! I never planned on fitting the ZX81+38 into an original enclosure and always figured that I'd create a custom case, so I didn't consider mechanical compatibility at all when making this. A number of people had asked if I could share the PCB or keycaps designs, so I bundled it all up on github, but I am in no way offended (or surprised) that folks may want to build their own (or modify mine).

One thing I'd suggest if someone wants to adjust the keycaps design is that you probably could either make the text a little larger or a little more spread out. I stayed entirely in the "safe" zone for printing, which avoids some of the curvature at the edges of the keycaps, but in hindsight I was maybe a little too conservative here.

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Fri Jun 16, 2023 2:08 pm

I created revision 1.10, electrically it is the same as revision 1.9, but some mounting holes have moved.
Only important if you want to use a real ZX81 case.

Its possible that PCBWay will make the ZX81+38 one of their projects. so you can directly order a PCB from them without even having tu upload gerber files. They are aware that revision 1.10 is the latest version.

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Fri Jun 30, 2023 12:52 pm

I'm now busy designing my own mechanical keyboard for the ZX81+38, mine will use cherry MX blue stem keys

Image

The 16 wire keyboard connector is placed so that it aligns with the keyboard connector on the main board when the keyboard is left aligned with the left side of the ZX81+38.

other mechanical keyboards often don't do this, and so need flexible wires to connect up.

with my keyboard you can use a rigid cable type FSN-23A-15 or FSN-23A-16 (15 pole when you cut the strip in two pieces where the unused middle pin of the LED connection is, so you need one less wire.)

Image

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Mon Jul 10, 2023 1:00 pm

the PCB looks like this!
sherry MX1A-E1NW keyboard preview.jpg
sherry MX1A-E1NW keyboard preview.jpg (134.76 KiB) Viewed 9164 times

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Tue Oct 24, 2023 10:48 pm

I'm working on a variation of the ZX81+38 that will fit into the case of the American version the TS1000, it will have the video output connector on a different location because the TS1000 used an American RF modulator with the RF output connector on another position
so I will swap the location of the RCA connector and the crystal oscillator. This new project will be named the TS1000plus41.

p.s. ordering the keyboard PCB's takes a while, so i'm considering uploading the gerber (production) files to github without having tested the keyboard PCB myself.

also I saw that the latest full set of kicad files is still the revision 1.9 version, I hope to replace that with revision 1.10 soon.

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Sun Nov 12, 2023 11:59 pm

I have uploaded the revision 1.10 version of the ZX81+38 KiCad files as promised.

I have also created a TS1000 (Timex sinclair) version of the ZX81+38 that has the RF output jack on the location where a TS1000 has its RF output, meaning you can use a TS1000 enclosure.
The name of this version is TS1000+41 (41 years after the original TS1000), and all the necessary files to create one (except for the component placement drawing, which is nearly identical to the one for the ZX81+38) are uploaded to a new repository on my mahjongg2 GitHub pages can be found here: https://github.com/mahjongg2/TS1000plus41

I have not yet ordered PCB's for my mechanical keyboard for the ZX81+38 but as I'm 99.9% sure it is correct I will soon upload it as another repository soon.

velectronico
Posts: 1
Joined: Tue Nov 14, 2023 2:58 pm

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Tue Nov 14, 2023 4:43 pm

Hello, I would like to congratulate the mahjongg project and the great conservation work for retro computing.

I show my assembly based on the mahjongg board to give life to a new zx81.
Clipboard01.jpg
Clipboard01.jpg (18.89 KiB) Viewed 5319 times
The casing is made with PVC electrical conduit cutouts. Each of the pieces have been joined with epoxy glue.

The keyboard has been made with microbuttons on a prototype board, and the keyboard sheet by laminating a printed copy of them, placed on a template that guarantees a firm surface.
Clipboard07.jpg
Clipboard07.jpg (31.15 KiB) Viewed 5319 times
After a lot of sanding and a few layers of paint, we have obtained a device that looks good and is totally functional.
Clipboard08.jpg
Clipboard08.jpg (22.95 KiB) Viewed 5319 times
Thank you for the great work done and congratulate you again for the project. :D :D :D

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Wed Nov 15, 2023 1:22 pm

I have uploaded the necessary files for the mechanical keyboard to a new GitHub repository here: https://github.com/mahjongg2/Mechanical ... ZX81plus38

oh, and great work velectronico ! :mrgreen:

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Wed Nov 29, 2023 10:31 pm

a fan has made a version of my PSG board with an SD-Card interface (I made for my ZX81+35 (the older sat version) specifically for a real ZX-81.
I tested if it would work for the ZX81+38 and with a few small changes it works, you can read about it here: https://revspace.nl/ZX81plus38_simple_t ... 1.2B38_too

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 15157
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: Build your own ZX-81 computer, from discrete pin-through hole components (schematics, gerbers and BOM on Github)

Wed Nov 29, 2023 10:42 pm

Thomas Schilling,, a fan of the ZX81+38, has made a version of my "ZX81+35 PSG board with an SD-Card interface" specifically for a normal ZX-81 built into a nice enclosure. He gifted me one as a thank you for my design work.

I tested if it would work for the ZX81+38 and with a few small changes it works! You can read about it here: https://revspace.nl/ZX81plus38_simple_t ... 1.2B38_too

The changes to the ZX81+38 needed were that JP1 must be switched from 16K ROM-space to 8K ROM-space, this is done by scratching a trace of JP1 on the underside of U25, and soldering a wire between the other two pins of JP1. Also you need to remove the static RAM chip on the zx81+38.

then you can plug in his PSG expansions into the ZX81+38 and use software that in 1982/1985 was written for the ZON-X80 PSG, a classical example would be dancing demon. There is a small collection of games that support the programmable sound generator (the AY-3-89xx PSG, that is also used in many other homecomputers of the time)

just as the version I made for the ZX81+35 his version also has the interface for a (micro) SD-Card, and he designed the patches that makes it work.

if you start the firmware with an USR call , in this case with L = USR 12345 a menu will appear showing upto 24 games, you can load and start a game by pressing a single letter, here is an example of such a menu.

Image

here you can see the PSG board plugged into a ZX81+38, you can also see that the RAM chip is removed.

Image

pressing 'T' wil start a packman clone, using the cursor key control choice you can play the game with the joystick interface of the ZX81+38.

Image

Return to “Off topic discussion”