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!

CR-Scan 01 – cheap 3D scanner

Only a quick one – I backed this thingy

Have followed it for a while before the public launch and I’m damned impressed with the quality of the scans at the price.

There’s a load of YouTube videos showing independent reviews and capabilities of the device, which has me extremely reassured

I’m gonna use it to scan the children in and create custom Heroquest miniatures!

Gonna try scanning a room, maybe a car, who knows what else 🙂 . it’s not designed for scanning 28mm miniatures, but a few people have videos up on youtube that suggests it can give a low detail scan ideal for a ‘starter’ form to add your own custom detail – which makes me very happy as i’m crap at organic modelling 🙂 also, now whilst I type, I realise I can scan KEYBOARDS in! – it’s detailed enough to get those pesky curves correct and allow me to model properly the C64 keyboard!! wooooo.

For a while I really wanted to upgrade my ancient iPhone 5SE to one that has lidar / time of flight sensors on board (iPhone 11 plus or higher) But the quality those devices produce is mediocre compared to dedicated scanners.

Don’t get me wrong, the iPhone ones are a massive enabler for all sorts of fantastic 3D mapping (caves!! It’s a paradigm shift in capabilities and accessibility, that’s just one example)

Put simply, cube capabilities of this scanner (and software package) exceed anything available at the price, and quite a lot available at the 4 digits in price.

So, if you’ve ever fancied scanning stuff and can’t be bothered with photogrammetry , get this!

Generic link below, zero referral or cash back from this link 🙂 I’m just that impressed with the company openness on this one, check the comments if you’re unsure! and the number of updates

https://www.kickstarter.com/projects/3dprintmill/creality-cr-scan-lizard-capturing-fine-details-of-view

https://www.kickstarter.com/projects/3dprintmill/creality-cr-scan-lizard-capturing-fine-details-of-view

https://www.kickstarter.com/projects/3dprintmill/creality-cr-scan-lizard-capturing-fine-details-of-view

https://www.kickstarter.com/projects/3dprintmill/creality-cr-scan-lizard-capturing-fine-details-of-view

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!