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 4 – Moar CAD

Have been tweaking things over and over, I’m now finally ready to…….

3D Print a sample!
And, the complete thing

I think there’s going to be a few people out there actually using this keyboard in anger, so i’ve widened the keyswitch tops a little and added larger fonts to make it easier for someone to fill in some colour if they chose to do so.

Some other progress –

The Floppy Disc insert! – a FULL scale floppy disc fits well

I’ve refined the floppy disc insert thingy – I really think I can make this work – lots of parts on order so i’ll iterate this design over the coming weeks. I’ll do the first prints of the plug in module soon

Alternate View – with the Clamp PCB in black, the A500Mini PCB in green

Speaking of prints….

I knocked up a few of the mini-Floppies. Printed in various orientations to see if it’s even possible to do these. The best print is the angled one..Turns out, it’s going to be tricky as can be seen from the various failures above. Have re-designed a little and will run off some more sample prints soon. The supports on this one will be critical and hopefully not so wasteful as the C64mini keycaps were.

And, almost finally –

Here’s a collection of ‘stuff’ rendered so far. The Keyboard PCB is unfortunatley upside down – due to the way I started modelling stuff, no big deal but makes the renders look odd. The case slopes don’t need to be modelled (at this time) so i’ve just left them flat for now.

There’s loads of parts waiting to arrive in the post, but there’s also loads I can be getting on with, not just on this project, but on numerous others also!

A500 Mini Keyboardification Chapter two, part 3 – PCB’s

I’ve spent a couple of days designing, and and a today, spent nearly a hundred quid at JLCPCB ordering a bunch of prototypes

The first revision of the Keyboard PCB
First ‘space sample’ of the top mounting board.
Floppy Disc Micro SD card holder!
Rear of the floppy discc.

I had to bite the bullet and spend some money as I now need to move on with the Keycap CAD. I have a big concern about the fitting of the printed keycaps onto the smaller switches. I’ve gone with ALPS switches as they used to be a huge brand name back in the day and i’m hoping should provide some consitency.

The prototypes will help also to test and develop the PRK Firmware i’m planning to use.

The ‘Clamp’ adaptor is fairly non-functional. It has a Rasperry Pi Pico footprint onboard and a 40 pin FPC style connector to act as a ‘stand-in’ for the Raspberry pi Pico which is currently on the back of the main PCB.

The whole idea of the ‘clamp board’ is to allow an ‘ease’ of installation – I’ll use some Pogo Pins to sit on the test pads by the 3 USB sockets on the back of the A500 Main board.

The plan is to have a basic matrix keyboard PCB, which connects to the clamp board via the 40 pin FPC.

The clamp then accesses the USB and hopefully it can all be fairly easy to assemble.

I’m also testing the Fake floppy connection with the clamp board – no idea if that’ll work or not, we’ll see.

Now the long-ish wait for Aliexpress to deliver my connectors, pogo pins, and a couple of weeks for the Cheapest post option of JLCPCB to ship the assembled keyboard! – nearly 100 switches and diodes on this one, those can be automated in assembly. I’ll need to hand solder on the rear the FPC connector but those are easy enough!

A500 Mini Keyboardification Chapter two, part 2 – Progress

This one’s a good ‘un

Progress to date has been surprisingly quick – most of the ‘easy’ stuff is now done and I’ve added some extra functionality. Most of the research is now done – have spent waaaaay too long googling connectors, Pogo pins and component types / dimensions.

First print of the keyboard PCB and CAD fitout – pretty close

My workflow generally is to eyeball, sketch, measure, adjust….Then when it’s close enough, i’ll print on paper, adjust in CAD, print again then………3D print

a 3D printed space sample

I’m quite chuffed – the first 3D print seems to fit reasonably well! – there’s some adjustments needed, mainly the top of the keycaps are a little too wide, but overall for a first run, not bad.

The PCB outline

To work out a PCB outline, I’ve scanned the A500 Mini on a flatbed scanner and trace around the important parts, measuring many with calipers

the Keycap CAD
Another view – the big circles are the curves / slight indents in the top of the kecays
The CAD compared to a scan of the actual A500 Mini

Before I 3D printed the sample, I put the A500Mini on a flatbed scanner to match up the holes – as you can see, it’s pretty darn close! – you’re seeing a canvas underneath the actual CAD model of the keycaps in Fusion. The Enter key is black as i’d discovered a slight profile error, so spent half hour correcting a 0.2mm height error 😛

But, wait, there’s TWO

During the design phase, there’s a process of discovery. My main discovery for the A500Mini keyboard was that….I’d possibly need TWO PCB’s!!

If you look above at the underside of the keyboard you’ll see that there’s no space on the top for electronic components! The PCB needs to mount entirely flush to the case of the Mini. This means I’d need a PCB assembly service that can handle double sided boards (a possibility) – And to also consider a two PCB solution. There’s cost and ease of install considerations for both ways.

The A500Mini has a number of test points on the back, I think using Pogo Pins I can maybe make a clip-on PCB that can securely tap off the USB test points, meaning, a solderless install! – hence the upper white PCB that sits in place of the A500 PCB above

And, now I believe I’m going to go with a THREE PCB solution…….because…

the one with the holes in sits above the stock PCB

That’s a scale floppy disc! with a Micro SD card in
quick render of the floppy slot in the case

I saw a few posts on facebook linking to a guy that’s made a ‘fake’ floppy insert for the A500Mini – https://www.printables.com/model/170947-amiga-500-mini-a500-mini-mini-floppy-disk?fbclid=IwAR3if5FRp3opclhKoTyrkUe63XQtRW-mckg2ymWSKKi1cZvSk1KuRRkzmR4

I figured I’d go one better and make a REAL fake floppy disc. and, the best thing, after several solid days of research and CAD testing, I believe it can work 🙂 – it’ll only need two small cuts inside the A500 case and be totally stock outside. there’s a little more tweaking needed for the floppy disc design to make the MicroSD slot more elegant . I’ve ordered a whole bunch of parts to physically trial this and see if it’s viable.

So, Summary. Still a long way to go, the Keyboard itself is the priority here, the ‘floppy disc’ is just a whimsy on my part for the time being, its development is secondary and may not even make it to a real release if it’s not robust enough.

Keycap CAD – Cosmetics finished, Just needs the ‘switch’ solution figured out

Main PCB – Outline finished, needs routing, quick job to finish

Secondary PCB – Outline finished, needs routing and Pogo Pin solution testing

Tertiary PCB for the floppy disc connector – Concept – parts ordered

Fourth + Fifth PCB’s – the floppy disc itself – parts ordered.

Firmware – Standard keyboard layout is done! – Just needs tweaking and testing on a real A500 Mini