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Show HN: ESP32S3 ZXSpectrum

109 points by iamflimflam1 2y ago

I've been playing around with ESP32 MCUs and displays for a while and finally got around to getting a ZX Spectrum emulator working. I then saw that you can now do full color silk screen printing on PCBs and got the thinking - the ESP32 has capacitive touch capabilities - I could make a full ZX Spectrum keyboard on a PCB along with all the electronics for running the emulator. And it actually works! There's a full video here: https://youtu.be/foP81O48WAI https://youtu.be/foP81O48WAI And you can sign up here for updates as I move towards getting it ready for a production run: https://esp32zx.substack.com/p/announcing-the-esp32-zx-spectrum https://esp32zx.substack.com/p/announcing-the-esp32-zx-spect... It's looks amazing, takes me back to my childhood.

iamflimflam1 2y ago
It will also be completely open source. The Z80 emulator I'm using is GPL, so all the firmware I write will be GPL. And the Schematics, PCB and Gerbers will all be available as a KiCad project for people to play with and even get assembled themselves.
gbraad 2y ago
I am not a fan of the Spectrum, but this looks like an interesting project. I believe a lot of this can be applied to the NES emulator for the ESP32.
jacknews 2y ago
Fantastic project and that colour silk-screen seems to work perfectly for this. It's not clear what size screen would be ideal though, as a 3-4" one will seema bit 'stuck on'. Maybe an option for a larger screen to make a 'spectrum clamshell laptop', and/or a video out to have no screen at all.
- iamflimflam1 2y ago
  In the next version, the screen will feel a lot more integrated. There is a bit of a challenge with larger screens as they tend to have more pixels and the MCU is pretty limited in how much it can push out at a good frame rate.
  - fl7305 2y ago
    Use a RP2040 or similar to handle the conversion from the Spectrum pixel output to what the display needs? And perhaps a small adapter board for the display FPC connector?
    - iamflimflam1 2y ago
      Been thinking exactly along those lines! But need to get this version actually done… so many rabbit holes :)
      - fl7305 2y ago
        I know, just spitballing :)
      - fl7305 2y ago
        Maybe mount the display on a small adapter PCB that has a CPU for pixel conversion, and a standard flat cable down to the main board? Then the main board can stay the same even as the displays are swapped out together with new adapter PCBs?
- numpad0 2y ago
  That size is about where the range for software hacker friendly products end. Minimum cost and complexity needed for a 4.8" and 6" LCD are substantially different.
andrewstuart 2y ago
I can recommend you dig through all the videos on this guys channel there’s lots of interesting projects. He is atomic14 on YouTube.
- iamflimflam1 2y ago
  Thanks! Some of the early videos are not great. But hopefully they’ve improved over time.
akubera 2y ago
Looks good. One note about the video: you mention you recently watched a good video on 1-bit sound, and suggest it's worth a watch, but it doesn't appear to be linked-to in the description.
- iamflimflam1 2y ago
  Oops - added it now - for reference it's this one: https://www.youtube.com/watch?v=N5ACJd2LvbY https://www.youtube.com/watch?v=N5ACJd2LvbY
camtarn 2y ago
The colour silk screening is gorgeous! Such a cool looking bit of hardware.
- iamflimflam1 2y ago
  It’s remarkably cheap as well. In the long run I think it will just be the same as standard silk screen. Just part of the process.
wdfx 2y ago
If you want to do a 128 model version and have it interface to a real AY sound chip, I've written ESP32 code for that: https://bitbucket.org/doughammond/fourays/src/master/ https://bitbucket.org/doughammond/fourays/src/master/
- iamflimflam1 2y ago
  Very cool!
bitwize 2y ago
It's really cool, but... somehow you managed to make the Speccy keyboard even worse :)
- iamflimflam1 2y ago
  Haha - I know! Who would have thought that was possible :)
bloopernova 2y ago
Oh lord, you just had to use a screenshot of Elite :) It looks utterly wonderful, I wish you every success in your production run! Makes me want to play Manic Miner.
thatgerhard 2y ago
this was my 1st computer and the 1st time I coded.. such nostalgia!
Cockbrand 2y ago
So nobody commented on the easter egg on the keyboard yet? Not sure whether I prefer it to the original, but I appreciate its existence :)
- tzot 2y ago
  OK, I give up; I can't find an easter egg, except maybe for the simulated “curve reflection” on the spectrum on the right (but I wouldn't call it an easter egg, so most probably it isn't what you mean).
  - Cockbrand 2y ago
    Hint: let’s assume that you want to get the value stored at a specific memory address.
  - Luc 2y ago
    On the O key, PEEK became GEEK.
anonzzzies 2y ago
That is fantastic! Well done. Please continue; it is something I want to do for the MSX, but didn’t get to (yet).
- helpfulContrib 2y ago
  [dead]
janekm 2y ago
You might be interested in knowing that LCSC (same company as JLCPCB) are about to offer proper panel / membrane keypad prototyping: https://www.lcsc.com/panel-printing https://www.lcsc.com/panel-printing
- iamflimflam1 2y ago
  That’s very interesting - thanks!
Boriel 2y ago
I created a ZX Spectrum BASIC compiler (compiles from BASIC to ZX Spectrum machine code). You might want to give it a try and run the programs in your device: https://github.com/boriel-basic/zxbasic https://github.com/boriel-basic/zxbasic
- alok-g 2y ago
  Very cool! Thanks!

109 points by iamflimflam1 2y ago

iamflimflam1 2y ago

It will also be completely open source. The Z80 emulator I'm using is GPL, so all the firmware I write will be GPL. And the Schematics, PCB and Gerbers will all be available as a KiCad project for people to play with and even get assembled themselves.

gbraad 2y ago

I am not a fan of the Spectrum, but this looks like an interesting project. I believe a lot of this can be applied to the NES emulator for the ESP32.

jacknews 2y ago

Fantastic project and that colour silk-screen seems to work perfectly for this. It's not clear what size screen would be ideal though, as a 3-4" one will seema bit 'stuck on'. Maybe an option for a larger screen to make a 'spectrum clamshell laptop', and/or a video out to have no screen at all.

iamflimflam1 2y ago
In the next version, the screen will feel a lot more integrated. There is a bit of a challenge with larger screens as they tend to have more pixels and the MCU is pretty limited in how much it can push out at a good frame rate.
- fl7305 2y ago
  Use a RP2040 or similar to handle the conversion from the Spectrum pixel output to what the display needs? And perhaps a small adapter board for the display FPC connector?
  - iamflimflam1 2y ago
    Been thinking exactly along those lines! But need to get this version actually done… so many rabbit holes :)
    - fl7305 2y ago
      I know, just spitballing :)
    - fl7305 2y ago
      Maybe mount the display on a small adapter PCB that has a CPU for pixel conversion, and a standard flat cable down to the main board? Then the main board can stay the same even as the displays are swapped out together with new adapter PCBs?
numpad0 2y ago
That size is about where the range for software hacker friendly products end. Minimum cost and complexity needed for a 4.8" and 6" LCD are substantially different.

andrewstuart 2y ago

I can recommend you dig through all the videos on this guys channel there’s lots of interesting projects. He is atomic14 on YouTube.

iamflimflam1 2y ago
Thanks! Some of the early videos are not great. But hopefully they’ve improved over time.

akubera 2y ago

Looks good. One note about the video: you mention you recently watched a good video on 1-bit sound, and suggest it's worth a watch, but it doesn't appear to be linked-to in the description.

iamflimflam1 2y ago
Oops - added it now - for reference it's this one: https://www.youtube.com/watch?v=N5ACJd2LvbY https://www.youtube.com/watch?v=N5ACJd2LvbY

camtarn 2y ago

The colour silk screening is gorgeous! Such a cool looking bit of hardware.

iamflimflam1 2y ago
It’s remarkably cheap as well. In the long run I think it will just be the same as standard silk screen. Just part of the process.

wdfx 2y ago

If you want to do a 128 model version and have it interface to a real AY sound chip, I've written ESP32 code for that: https://bitbucket.org/doughammond/fourays/src/master/ https://bitbucket.org/doughammond/fourays/src/master/

iamflimflam1 2y ago
Very cool!

bitwize 2y ago

It's really cool, but... somehow you managed to make the Speccy keyboard even worse :)

iamflimflam1 2y ago
Haha - I know! Who would have thought that was possible :)

bloopernova 2y ago

Oh lord, you just had to use a screenshot of Elite :) It looks utterly wonderful, I wish you every success in your production run! Makes me want to play Manic Miner.

thatgerhard 2y ago

this was my 1st computer and the 1st time I coded.. such nostalgia!

Cockbrand 2y ago

So nobody commented on the easter egg on the keyboard yet? Not sure whether I prefer it to the original, but I appreciate its existence :)

tzot 2y ago
OK, I give up; I can't find an easter egg, except maybe for the simulated “curve reflection” on the spectrum on the right (but I wouldn't call it an easter egg, so most probably it isn't what you mean).
- Cockbrand 2y ago
  Hint: let’s assume that you want to get the value stored at a specific memory address.
- Luc 2y ago
  On the O key, PEEK became GEEK.

anonzzzies 2y ago

That is fantastic! Well done. Please continue; it is something I want to do for the MSX, but didn’t get to (yet).

helpfulContrib 2y ago
[dead]

janekm 2y ago

You might be interested in knowing that LCSC (same company as JLCPCB) are about to offer proper panel / membrane keypad prototyping: https://www.lcsc.com/panel-printing https://www.lcsc.com/panel-printing

iamflimflam1 2y ago
That’s very interesting - thanks!

Boriel 2y ago

I created a ZX Spectrum BASIC compiler (compiles from BASIC to ZX Spectrum machine code). You might want to give it a try and run the programs in your device: https://github.com/boriel-basic/zxbasic https://github.com/boriel-basic/zxbasic

alok-g 2y ago
Very cool! Thanks!