Show HN: ESP32S3 ZXSpectrum

[iamflimflam1]

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

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-spect...

It's looks amazing, takes me back to my childhood.

[iamflimflam1]

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.

[wdfx]

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/

[iamflimflam1 → wdfx]

Very cool!

[Boriel]

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

[alok-g → Boriel]

Very cool! Thanks!

[bloopernova]

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.

[janekm]

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

[iamflimflam1 → janekm]

That’s very interesting - thanks!

[bitwize]

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

[iamflimflam1 → bitwize]

Haha - I know! Who would have thought that was possible :)

[camtarn]

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

[iamflimflam1 → camtarn]

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.

[akubera]

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 → akubera]

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

[jacknews]

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 → jacknews]

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 → iamflimflam1]

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 → fl7305]

Been thinking exactly along those lines! But need to get this version actually done… so many rabbit holes :)

[fl7305 → iamflimflam1]

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?

[fl7305 → iamflimflam1]

I know, just spitballing :)

[numpad0 → jacknews]

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]

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 → andrewstuart]

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

[gbraad]

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.

[Cockbrand]

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 → Cockbrand]

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 → tzot]

Hint: let’s assume that you want to get the value stored at a specific memory address.

[Luc → tzot]

On the O key, PEEK became GEEK.

[anonzzzies]

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

[thatgerhard]

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