A500 Mini Keyboard – prototype 2 – progress

I’ve tonight finished routing the new PCB and switches!

A lot of work has gone into this! It’s got some ‘extras’ , it’s also an expensive board at 4 layers , 1.2mm thick and nearly 100 switches!

I’ll get to designing the other 2 or 3 (maybe even 4!) PCB’s needed for the complete setup, then place a single order for them all, so it’ll be a few weeks till I can test this beast out!

If they work, Ill make few ‘special limited edition’ early ones to send out, I’ll not spoil the surprise extra features till they’re in my hands!

A500 Mini Keyboard – D’oh! More work needed

Nah, that looks crap.

Well, that’s a wrap for idea 1 – concept was ok enough, but…it’s no-where near good enough for a production run.

After half a dozen trial prints and practice fittings, I’m heading down another path.

The Many faults include

Keys fitting poorly to switches.

Keys not fitting on switches straight

Keys just not fitting onto switches at all

The attached picture sums it up really.

All is not lost however. This is something I had to trial, if it worked, it would have been cheaper and awesome.

I have a few ideas up my sleeve…My next option is right now, considerably more expensive, but has been underway for a few weeks now, I’ll reveal a bit more once the process is done.

On the plus side, the keycaps look great in Amiga Beige! – I’ll work on the darker caps another time.

The PCB layout works great, firmware works, so, really, it’s down to the thing that always was going to be an issue, the switches!

A500 Mini – part 8 – partly working keycaps and a small PCB reveal

First working keyboard keycaps are off the printer!
Only this bit to show as most of the print failed 😛

Well,, 3 prints failed, I’m trying to learn how to use my Photon Mono-X, so far mostly unsuccessfully, these were printed using a known good combination of Photon Mono and Commodore Brown resin 🙂 ….and still it partly failed!!

Next, I have to optimise the design for printing.
I’d added some features to make them work better, but, those features don’t translate to printing very well, D’oh! (That’s called not doing Design For Manufacture!).

Resin printing can be a hard beast to tame, especially when printing 94/98 individual items (98 if I can two keyboard types!!)

This first print is literally an ‘auto supports, Jab a few extras on, hope for the best’ quick test to prove the mechanics.
When the design is finished,
I’ll need to spend a couple of solid DAYS (maybe a weeks worth of evenings) adding thousands of supports MANUALLY to ensure every keycap comes off the print perfect!

That sounds a lot, but printing a single item is different than printing the same item hundreds of times, so it’s really worth the up front investment in time.

And, speaking of time, I’ve just clocked about 600 hours evenings and weekends, on this project now 😛

I’m rather happy otherwise, next week, I should have a full working keybaord to demonstrate 🙂

Another failure
Another failure!

And, the reveal, part 2

It’s here!!!!

A500 Mini II Part 7 – other ‘stuff’

Along the way, I’ve been tweaking some other bits – The Real miniature fake USB Floppy disc is progressing nicely

IT FITS!!

I’m on the second design of the 3D Printed insert, this will hold the USB PCB and also be the interface and guide rails for the floppy.

I’ve also received my memory solution for the discs, it fits superbly! – it can be seen in the badly printed / broken green area. The dimensions are exactly the same as the 3D print i’ve put in

I’ve also purchased some silver brushed effect sticky foil so I can re-create that beloved silver cover….and even have created the label ready to cut out on my dusty KNK ZING vinyl cutter thingy. Hopefully I can make the adhesive sticky enough!

A Floppy fits in the drive!
Tiny

The silver ‘label’

I’ve also started stocking up on Printer resin, ordered a load of sample parts from Aliexpress, test fitted PCB’s…..started on box design, started tweaking firmware, there’s dozens of tasks to do!

A500 Mini II Part 6 – past the half way mark! – keycaps

Quite a lot of progress, but it doesn’t look like a lot of progress.

Firstly, I’ve had to re-do most of the keyboard CAD – I simply didn’t like the ‘blocky’ effect of the wider topped keycaps I’d created – as you can see below they look a lot more square in real life than they did in CAD…

I’ve now clocked well over 200 hours developing this set of keycaps, likley there’s going to be tens more tweaking / optimising!

So, along with the less blocky (more slopey) keys, I’d discovered my workflow in CAD had created tapered keys – the tops when viewed from above look like parallelograms, wheras the original Amiga had more square keys – it was quite a lot of work to alter this – see the parts below by the red arrows – the bottom bit is in towards the middle more than the top bit.

Tops not parallel with bottoms
Tops are parallel with bottoms
Continue reading “A500 Mini II Part 6 – past the half way mark! – keycaps”

A500 Mini Keyboardification Chapter two, part 1…The Evisceration and Dimensionality

I received yesterday my A500 Mini! – Haven’t even powered it up yet 😛

My assumption about the 43ish percent scale was about right – and the work i’ve done so far on the PCB pretty much stays the same – which is a relief.

However, till now i’ve been using a full sized Amiga 500 to infer dimensions. I can’t easily do that going forward as the scaling factor for the Amiga is ‘a bit weird’ – I think I can see why it’s been done, but, it’s far far easier to re-start the CAD from new…or at least shift the fusion timeline back to the beginning and see what i can recover 🙂

Much more to do, will update later as there’s also a few ‘gotcha’s i’ve found, and a few ‘woo’ moments also!

Dimensioned to within about 0.3mm

Spmeone should hide my screwdrivers

A500Mini keyboardification – alternate technology

Had a major ‘procrastination’ research binge over this past week, trying to figure out just how I could cheaply and reliably get 3D printed keycaps onto tiny switches.

I’ve found I think two ways that can be successful.

The first – a small tactile switch, with an ‘oval’ or keyed button. The A500mini’s keys are probably just over 7mm square, I can’t use the 6mm switches i’ve previously used as there’s not enough space.

Something like the below could do the job – it has a slightly tapered switching bit in the middle, so I can do push fit keycaps that should grip on. it’s also 5mm on a side, and 3mm on the other, this frees a huge amount of PCB space up, BUT, it’s still quite ‘large’ and the top isn’t tapered as much as i’d like. visually it looks fine, but datasheet suggests it’s straight

There’s also an older, more ‘retro’ type of approach. So, i’ve gone and knocked up a very rough CAD drawing – it’s innacurate, until I get an actual A500Mini in my hands…

and i’ve gone and emailed half a dozen companies to request some MOQ’s. and some pricing!. I’ll fill this in later with more specifics

In other progress – the A500Mini Manual is now available – and, the Keymap is shockingly simple 🙂

So, that means getting firmware working should be a breeze.

There’s becoming quite a few ‘RP2040’ public circuits available now, so that part’s done and dusted on my PCB, all i’m really waiting for is to get some accurate measurements so I can knock up a prototype!

A500Minier (than 50%)

All along, I’ve been assuming the A500Mini will be the same 50% scale that the C64Mini is

Thanks to https://youtu.be/h552-eR0cGA Retro Recipies

And https://youtu.be/igEpW8QJFQ4 8abit guy

I’ve been able to get an idea of the size of the A500mini

A500Mini

Using the USB socket size to scale, they’re about 13.2mm in real life.

We get about 186mm for the keyboard width.

The real A500 has a keyboard cutout width of about 450mm

186/450 = about 41.3%

So, summary, it’s closer to 40% scale than 50%

And, I gotta figure out a whole new way of keyboardification:-p darn you rascals at Retrogames LTD :-p

A500Mini Keyboardification – Part 6 or 7 I think

Minor update on progress…made the schematic a bit clearer for me to understand, also am doing a dual footprint style setup – where I overlay multiple component footprints incase one becomes hard to get.

I’m also creating two ways of driving the matrix, an on-board RP2040 chip and, if they become hard to get, a seperate daughterboard which can house a Pi Pico

Kinda pausing PCB development until my Amiga 500 Mini device arrives in the post, but i’ll be playing with the PRK firmware next!

More A500 Mini

Working on the Fonts now for the keycaps!

after a good half hour of searching for the Amiga Key font, including various terms like “lop sided font”, “font with one side thicker than the other”, “fonts that look like broadway, “broadway serif” and even google image search for

I finally found the correct font with a quick search for “font used for Amiga key”

https://deskthority.net/wiki/Amiga_key

and, the Font – is Garamond-Bold-Italic

So, now we have the following two keys!

and, extruding that A to create a solid A, then projecting to a sketch, offsetting that sketch and extruding into the key….

we have…The other Amiga Key!

Now to figure out the rest of the keyboard 🙂

A500 Mini Part 6

Another small update! – I think i’ve cracked the basic model of the keyboard.

To get this far has taken dozens of hours of interweb sleuthing and watching youtube videos to watch how the light reflects of genuine amiga keboards to see how i can capture the curves of the keys.

Most keys seem to be a very simple U shaped dip from the edges of the keys! the dip is always the same depth, so the wider the key, the smoother the dip!

Two different keys were the Space bar – this has a slightl raised curve at the top ratther than a ‘dip’

and the Enter key – which has a more complex bowl like dip in, that key probaly took the longest to figure out but the top is essentially is two U shaped dips, one for the top of the key, one for the bottom. I’ll go into more detail in a future post

simple hidden edges image
Nice render on a snowfield to show the curves

For now, this is accurate enough for me to be able to develop the font to embed in the keys! I’ve made the model reasonably parametric so I can change things around a little to match the exact key spacing of the mini once I receive it. At this scale, i’ll have the same 0.5mm clearance between keys as I had on the C64 mini, though I plan to increase it a little more in the final product.

A500 Mini Keyboard Part 5

Small updates – keyboard keycaps progress!

Not much of an update, just a couple of pictures to show i’m still slowly tinkering.

The keys do seem much easier to model as they’re less curvy. there’s only a top ‘dip’ in one plane which is easily extruded into the keys using circles that are varying radius’s to give a 0.9mm ‘dip’ in the top of the key. that dip will be much less prominent when the whole thing is shrunk 50%, but I like to try to be reasonably accurate.

One key from each row complete!