Wanted: Acorn Electron (not working)

I’m after an Acorn Electron for an upcoming project (don’t worry – its not the PiCopter…think I might struggle to get the Electron flying!)

Essentially this will involve stripping it down so I just have the keyboard and case and then replacing the main circuit board with a Raspberry Pi as well as some other circuits (amplifier, USB hub, Ethernet, etc).

Since I’m going to be gutting the Electron I’m after one that doesn’t work because it would be a shame to hurt one that was alive…

Funnily enough, I was looking at doing something similar with an old A3020 I have (transformer tore itself off the circuit board in transit and they’re virtually impossible to find replacements for).

The one thing I hadn’t figured out how to do was to use the original keyboard – I’d be interested to know how you’re planning on doing it. GPIO?

I think we have a PSU transformer for A3010 (A3020?) in stock

Nuts – wish I’d known about that at the time. I ended up buying another one. That said, I’m still tempted, just to have a spare motherboard.

(I still fancy the idea of a Pi-powered A3020)

I did think about the A3020, but like the neatness of the Electron – although if I were to do one with a USB floppy drive then the A3020 case would be the way to go!

@Chris: You don’t happen to have an old Electron gathering dust in your warehouse do you?

I’ll probably be coming to you guys for some HDMI/USB/Ethernet flying leads anyway although I still haven’t finalized what I plan on doing but I think the Pi will be fully embedded in the Electron case and everything will be broken out on flying leads through existing holes (possibly made slightly larger).

Yep – the potential for USB floppy was something I considered too, though sadly you’d not be able to read/write non-FAT formatted disks, I guess. The other thing that helped was that the keyboard layout is at least vaguely modern (and obviously, spot-on for RISCOS).

The keyboard is a minor concern, but I think as long as I remap it to something standard it will be OK (I plan on using this computer for writing mainly and don’t need to look at the keys to type – my current writing computer has some non-standard keycaps (so I could get them all white I ended up using a mixture of American and UK sets so the symbols are a bit mixed up) and I’ve never had an issue with that – so long as the characters are where my finger-memory expects them to be I reckon it’ll be OK).

The inspiration behind this project was an instructable (clicky) which involves using a Freescale FRDM-KL25Z as the keyboard controller – I reckon it would just be a case of modifying the firmware program provided as part of that instructable so that the keyboard layout matches what I’m used to.

Of course the lack of arrow keys and a small enter key are a worry and I don’t know how functional the “CAPS LK FUNC” key is in the instructable.

All that said and done, at the very least it’ll be a fun project! :—)

Glen: We do have some old Electrons but even non working units are not cheap. I’ll put them on our website when I can find time. Which may not be for a couple of weeks, we have the SW Show this Saturday and the following we have a presence at the Raspberry Pi 3rd birthday bash. Oh and the launch of a number of new products to sort…

I’ll put them on our website when I can find time. Which may not be for a couple of weeks

Thanks Chris! :—)

No worries about the timescale – I need to buy other stuff first, not least a decent vice and new soldering iron so see this as a long-term project anyway. Good luck with the show and new products!

Hi Glen.
This sounds like a really interesting project.
I read in micromart about someone who was converting old sinclairs in a similar way, taking the guts out and creating either a pi-powered spectrum or converting it to a usb keyboard.
I’d love my old electron to have a new lease of life (since its demise in the early 90’s!) and found this article from last year which you may find useful: instructables

It would be great if you could keep us updated as to your progress – obviously no rush as life seems to be full of little projects to take up time!

Over on StarDot, we’re starting to think about what it would take to resurrect Electrons with broken ULAs, inspired by the work done on second processors for the Atom. If people are looking to fix their Electrons, there are quite a few people on the StarDot forums who can help.

The one thing I hadn’t figured out how to do was to use the original keyboard – I’d be interested to know how you’re planning on doing it. GPIO?

There’s this that may help?

As part of our RISC OS laptop project we (Simon is doing nearly all the hard work) are working on a ‘any’ bare keyboard matrix to USB interface. It should open up a few interesting possibilities.

Yep – the potential for USB floppy was something I considered too, though sadly you’d not be able to read/write non-FAT formatted disks, I guess

My brother has just started work recovering some Amiga disks using Project Kryoflux

From a quick reading of the website there’s no reason it couldn’t be used for a built in floppy drive for a converted A3020…

If I get bored one day I might buy a USB floppy drive and get it working under RISC OS. It’ll be useless to most people, but I’d imagine it would be pretty useful to people who are returning to RISC OS after skipping the Iyonix and want to get some data off of an old Arc or RiscPC which isn’t connected to the network (assuming their old machine still works at all!)

Of course native Kryoflux support would be good as well, but I’m not that crazy quite yet ;-)

Its been a while but I have been busy working at a new job…anyway I have found someone who has done the hard work of stripping out an old Electron to make it into a USB keyboard. I e-mailed him and he is also able to build it with a Pi inside if you wanted to make a small RISC OS computer: TynemouthSoftware

It would be cute to see an Archimedes version! (Pi inside an A300/400 keyboard case with mouse)

(Pi inside an A300/400 keyboard case with mouse)

I’m not sure the A300 series keyboard has enough space inside to hold a Pi. It’s rather thin. As for the A310 base unit, there would be plenty of room inside. A ridiculous amount of room. ;-)

Mmm… I wonder if one might get somewhere with the Compute module? That’s flatter, and the edge-connector arrangement means that the I/O could be routed to the back of the keyboard casing instead of being constrained by the size and layout of the Pi itself (which has I/O on all four sides)…

Yeah, it’s probably not do-able. I wonder if there is any mileage in making a wedge-shaped ‘dock’ which fits under a typical PC/USB keyboard, providing room for a Pi etc.? I want to build something like this so I can have a portable-ish Archimedes games console to plug into a TV. One day, I’ll make a decision…

I wonder if there is any mileage in making a wedge-shaped ‘dock’ which fits under a typical PC/USB keyboard, providing room for a Pi etc.?

It probably depends on the keyboard.

The one I’m typing this on, for example, has two nice insets running almost its full width underneath. With the legs out and some cuts made, there would be room for a Pi underneath – except I can’t have the legs out, because there’s only one of them. I’m guessing the other probably decided not to come home with me after one of last year’s shows.

OTOH, a more recent bog standard cheap £5.99 or whatever keyboard I’ve bought would not accommodate a Pi underneath.

Hmm, yes, I guess it’s all a matter of picking the right keyboard. For a whiff of authenticity, maybe I should use a Risc PC one? (complete with PS/2 to USB adapter)

I’m wondering if constructing some sort of ‘tray’ which holds the keyboard/mouse and tidies away the Pi (and wifi adapter etc.) might be the solution.

My RiscPC keyboard has a tray-like extension below the keyboard to house the interface board; it is not slim like those you buy today. By my measurements, there is room in that tray for a Pi, with a bit of adaptation of the rear, where the power and HDMI sockets will appear. I have not done any actual work on this, but you have prompted me to think again. ;-)

I have the keyboard available because I have put my RPC to sleep. In taking it apart I found nearly 20 years worth of crud – not a pretty sight.

Presumably that’s not the standard Acorn keyboard?

It is the one supplied with my Risc PC in 1995. There are a couple of pictures at:

Ooh. It’s a ps2 plug. That means the keyboard I got with my RiscPC ought to work on my P4 box ¹. :-)

¹ It is kinda cool. No (E)ISA or any of that rubbish, but it does have serial, parallel, and ps2 twice, in addition to something like eight USB ports. Nice to see the old tech isn’t dead yet – serial is still useful for things…