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Show HN: ESP32S3 ZXSpectrum

109 points by iamflimflam1 ↗ HN
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.

31 comments

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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.

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.
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
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
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
Been thinking exactly along those lines! But need to get this version actually done… so many rabbit holes :)
fl7305
I know, just spitballing :)
fl7305
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
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
Thanks! Some of the early videos are not great. But hopefully they’ve improved over time.
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.
camtarn
The colour silk screening is gorgeous! Such a cool looking bit of hardware.
iamflimflam1
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.
bitwize
It's really cool, but... somehow you managed to make the Speccy keyboard even worse :)
iamflimflam1
Haha - I know! Who would have thought that was possible :)
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.

thatgerhard
this was my 1st computer and the 1st time I coded.. such nostalgia!
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
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
Hint: let’s assume that you want to get the value stored at a specific memory address.
Luc
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).