Spectrum Next Mini – SD card

The Xberry pi’s SD card slot location isn’t ideal when putting inside a Scale Next Mini.

With the HDMI, EAR and power sockets all aligned to the back of the case, the micro SD slot sits about 13mm too close to the rear from where the ideal location would be on the side of the Next. – As can be seen below

It also sits about 30-35mm too far from the side of the case. So, an adaptor is needed. You can buy these ‘micro Sd / TF extenders’ – But, none in just the right length (they’re close), nor in a slight offsetty-typey thingy.

‘off the shelf’ Micro SD extenders

So, i’ve had to knock up yet another PCB!

Presenting the SD card offsetor thingymajig.

Turns out there’s a few projects online that use 0.6mm thick or 0.8mm thick PCB’s to plug into a standard slot and extend out TF / Micro Sd cards. Micro Sd cards are 0.7mm thick though, and few ‘cheap’ PCB places seem to do that thickness…

I’m going to try both and see what happens. Seems most have success with 0.8mm.

And, here’s the board sitting inside the Next Mini!

I suspect this board may change in size a little as it’s probably going to be easy to re-purpose it also for the 3 side buttons.

And, before you ask, Yep, all this is so that the Next Mini looks very close to the original, I think I’m close!

The reason my one looks ‘stumpy’ is that it’s exactly 50% of the length and width of the Next, but is exactly the same height!

New PCB – Next Mini DB9 Thingy

Had some issues fitting everything inside the Next Mini case…I’ve almost wanted to dump the exactly 50% scale idea…

The Problem – Commercial DB9 connectors are cheap and plentiful

They’re just simple joystick connectors after all..many 80’s and 90’s consoles / computers used them.

Here’s a quick preview of one of my browser windows after spending a good 4 hours hunting for ones I specifically need

The Xberry Pi just doesn’t fit very easily into a 50% Scale Next mini case without some jiggery pokery. I want the case to be easy to remove from the Xberry so this means no mods. It was practically impossible to find suitable connectors to mount on my interposer PCB. I needed slim, not sticking out too far and right angled PCB mount.

I found a few , but even their footprints clashed a little and it left the joystick connector just a bit too close to the coloured strips edge of the case…….

BUT, a quick brainwave – Do as i did with the C64-Mini!, mount solder bucket joystick ports on the edge of the PCB……

Voila

And, here’s where it sits in the grand scheme of things!

Here’s a render of the rear of the case

I’ve spotted that some Design For Manufacture will be needed on the rear of the case as the thickness below the DB9 is just over 1mm. The PS/2 port isn’t much more, so i’ll probably need to cut out the bottom of the cutout and put it on the bottom of the case. might leave an ugly seam if I get it wrong, but we’ll see.

Now, to tackle the PS/2 Connector and power LED. The Keyboard connector is proving problematic also due to lack of space, may have to get creative with yet another custom PCB!

Spectrum Next Mini Progress

Had chance to spend some quality time with my loved ones The computer. Have started on the final stages of getting the Next Mini ready.

Needed to finesse the keyboard design a little to allow for better fitting inside the Next mini. Have been mindful that it’s also designed to be standalone so the PCB isn’t an ‘odd’ custom shape like my previous iterations were and can be easily sit inside a standard rectangular case if need be.

Have designed a Middle board (in yellow in the images) to accommodate the PS2 (keyboard / mouse), DB9 (Joystick) , Power LED, Micro SD slot and the side buttons. I’m planning on using the Xberry Pi without any mods so it complicates things a little.

Still not quite sure how to handle all of those electrically yet – but there’s quite a few options available, even if worst case, someone has to solder a bunch of wires in place

XBerry Pi based Next Mini
Cutaway view

If you count the Rasperry Pi zero, and the ESP-01 wifi device, there’s FOUR layers of PCB’s, two custom PCB’s and over 70 3D printed items (well, less than 20 if you now count the keycaps as 5 items which is how they come off the printer!)

Just spotted that i’ve not put the power LED in place yet…then there’s the potential blinkenator-ish illuminated inserts, then, then, then…………

Famous! A little bit :-)

That’s Me!

It was the 12th Anniversary of the launch of the Raspberry Pi . I was one of the fortunate owners of the first ever First 10,000 units. Fell in love and have purchased tens of the things since.

They also released an official magazine to accompany the product – The MagPi Magazine

Today, with the release of Issue 139 my Amiga Mini keyboard project has been featured over two pages 🙂

I’m chuffed to beans!

Go buy your copy in the shops next week, buy the PDF, subscribe, or wait a month or two to download as PDF back issue for free!

That’s all for now!

A world first? Dual colour MSLA resin printed keycaps!

Ok, they’re not perfect yet…the process just needs a little dialling in.

I’ve googled a little, I really do think I’ve done something unique! Me, a mid 40’s Welsh bloke doing something no one else has…

I genuinely think this has never been done before…

Happy to be proven wrong 🙂

Trying to be a perfectionist! (Next Mini)

It’s been a couple of weeks of iteration and maybe ten actual prints between these two prints!

In person, the difference is very notable. more subtle in pictures.

This is as good as it gets for a standard set of keycaps 🙂 I’m finally happy.

Now I can really get stuck into experimenting with getting those legends white! I have three ideas, one may be limited somewhat by the viscosity of water!

Spot the difference!

Spectrum next Mini – updates – almost there!

Have done a good amount this past week – Finally received the 2mm pitch ribbon cables so decided to test the boards……

…Aaand, something wasn’t correct – lots of keys jumbled up.

So, had to spend an hour or two diagnosing!…and to do that I knocked up a quick spreadsheet to cross reference. I had a similar problem with my C64 Mini, so suspected it was simple ‘swapped pins’ – But was worried as to how I goofed it up….

Continue reading “Spectrum next Mini – updates – almost there!”

More Next mini keyboard stuff! first partial success

Did another Spectrum Next mini keycap print overnight (it’s a 45 minute print at the moment)

Lots of optimisation needed, but happy that the keycaps actually just about fit for this second print!

Issues noted here

1 – elephants foot , the first few layers bulged out a bit, causing smaller holes and a rough surround when removed

– fix, either compensate for, or raise off the bed and use supports. Using supports will also make it easier to remove the keycaps off the print bed.

2 – possible issue with switch fragility. And friction fit.

– fix, have to ensure the holes are the correct size, possibly incorporate a mechanism to allow glueing in place as a pure friction fit may not have suitable longevity.

3 – uniformity of finish when installed

– fix, minor design changes and good hole cleaning to ensure each keycap sits at the same height on the switches, even if they’re printed slightly different.

All fairly easy / minor stuff, but it’s always this final touches stuff that takes the most time.

It’s a Spectrum keyboard!…or, is it.

I’d easily gone through 20 iterations to get the C64mini keycaps perfect to print every time – and more later on as I’d learned more about resin printing and how environmental conditions affect prints!

This one will be less than ten iterations to perfect I think, so a few months yet, BUT, as I’m iterating with this, I’m also using lessons for the new C64 mini and new Amiga mini keyboards…so all three projects are sped up by doing three simultaneously!

I also say months (even though it’s realistically a day or two’s worth of hours) as real life takes over. Work, schools, after schools clubs, weekend clubs, dog, house renovations and sleep (I really need to do that one more) all add up to Twenty eight hours a day, leaving me with -4 hours tinkering time :-p

Tiny keycaps – Spectrum Next Mini.

Spot the goof up!
Four by four makes one!

I’m going to write to those Fox’s Glacier Mints people and suggest they make tasty keycaps!

After two days of hunting, Found a paint scraper to remove the keycaps off the printer !

Also Bought some IPA to clean the keycaps up…

But…I’d forgot to actually prepare the slicer properly for printing.

I’d planned to just print straight on the bed without supports.

I forgot to remove the first base layers / brim / whatever it’s called so there’s no hole on the underside of the keycaps!

Ah well!

I’ll re-slice and reprint tonight, it’s an hour to print, so very quick to iterate!

Also, can’t find my curing station, and it’s raining today…d’oh!

It’s Alive! – The A500 Mini keyboard

Janky test rig.

After a few hours of fault finding, PCB bodging and praying for leniency from the magic-smoke letting out gods….

I’ve plugged the keyboard in to a somewhat nekkid A500 Mini.

Now I’m torn between carrying on working or owning all the high scores!

Heck, I could procrastinate heavily by firing up workbench and give the keyboard and mouse a really good seeing to!

But…I won’t!

The hardware is now fine, I’ve adjusted the schematic to fix the issues.

I’ve also done a little DFM and used larger, cheaper anti ghosting diodes due to finding issues with two of the teeeeny SOD-923 diodes preventing the CTRL and Left Amiga keys working.

Im now using a much larger SOD-323

(You can just about fit 5 smaller ones in the whole footprint)

These larger diodes should minimise Pick and Place issues at the PCBA company as they’re easier to grab and likley will have an easier soldering temperature profile when next to the relatively giant switches.

Larger diodes will also provide more test points , which makes testing easier and quicker!

When making large batches, every minute saved adds up quickly!

If I make 100…and testing time is reduced by 2 minutes due to adding diodes, that’ll be over 3 hours saves just on one test!

You can see how a weekend would quickly get eaten up and achieving very little!

Prototypes – Phew Silly mistakes – A500 Mini

Always knock up prototypes before doing bigger numbers of PCB’s

Had a bit of a quandry doing some quick rough testing on the A500 Mini keyboard – some keys just don’t work!

Keyboards are generally made of a simple matrix of ‘rows and columns’ – so spotting patterns in faults makes diagnosis much easier.

Here, most of the missing keys are on Column 2 in the schematic! – so, clearly there’s an issue somewhere with Column C

Which goes to this pin on the raspberry pi

So, using the scope to quickly check all the buttons – seems that ‘something’ stops after button I to prevent button O working……..

Had a quick nose at the schematic and………..(i’ve circled the missing thing)

Yep, I’ve missed the connection between the switches!

Also, i’ve missed another connection or two elsewhere i’ll guess, looking at that 1,2,3,4 buttons not working

Why was this missed?

I’m partly lazy….

Rather than design a whole new symbol and footprint for the switch, I re-used an old symbol – meaning, in the schematic, the switch looks like the below…..

Pins 1&2 are joined internally, as are 3&4 – so really it doesn’t matter if they’re joined on the schematic or not…..

Unless……..you run out of space on a dual layer PCB to join all of the nets up, and you know they don’t matter, so, you ignore the Design Rule Checks (DRC)

I did, thinking that I’d cleverly pick everything up myself!…

But, clearly I didn’t

So lesson is – setup for success – make the schematic correct, don’t do shortcuts, else you’ll increase the chances of failure!

Fortunately, a few small bodge wires can easily fix these silly mistakes for the prototypes and Beta test versions

Next Mini keyboard – ready to print!

But, forgot to buy IPA to clean the thing off once printed.

Found a Very well priced 5L of 100% IPA at Sydney Solvents for $35 delivered!

Now, if in a rush, I could pay $10 for 125ML at Bunnings

Here

Or even a more reasonable 250Ml for $14 at Jaycar

Here

(They even have 5L for $76!!)

But, I’m stingy, anticipate that I’ll need quite a bit (even though it took me two years to not use 5L back in the UK due to fastidious recycling)

So, summary, I’ll

Be printing key caps next week at the latest!

Then I’ll re-do the Next mini PCB a little bit too!

Prototype mini keyboards have arrived!

As suspected, a few minor goof-ups already spotted on the Next mini one, and the C64 one too. The Amiga one’s looking ok so far….

Still a few weeks of testing needed though before a production run can happen!

Sinclair Spectrum Next mini, next to an Xberry Pi.
All the minis

Prototype keyboards incoming

Woooo!

Should be here next week, not long till I find out how badly I’ve cocked them all up and how much work needed for a re-spin for production!

I purchased 2000 switches so can re-spin and re-test one, possibly two depending on which one (the Amiga needs 500 switches for 5 keyboards, spectrum needs far fewer!!)

Exciting times, now gotta get off my bum and fire the resin printers up.

Yep, these are WORKING keyboards for the

The A500 Mini Amiga

The C64 Mini Commodore 64

And

The Spectrum Next Mini (an Xberry Pi case) which is a 50% X &Y (100% Z) scale next mini styled case.

More Xberry Pi / Spectrum Next Mini!

Picture heavy this post!

The Keyboards (Spectrum Next Mini, The A500 Mini and TheC64 Mini) are actually being made right now at JLCPCB – The Keyswitches arrived, were checked and manufacturing is go!

So, in the meanwhile, I’ve been playing around with the Next mini case – My original design was a proper , almost exact 50% scale. That means you place 4 of them in a square next to each other 2×2. Then Stack another 4 on top.

So That’s EIGHT spectrum Next mini’s, stacked in a ‘cube’ of 2x2x2…

Recently, Some clever guy Released the Xberry Pi, A ‘credit card’ sized Spectrum Next that can fit in a Raspberry Pi case…

Of course, it wouldn’t fit inside my Next Mini! There’s just not enough space inside to fit a keyboard and this….Infact, this thing needs exactly the same amount of height as a full sized Spectrum Next!

So, after some re-jigging, I’ve now made the Next Chibi (name, work in progress)

This version keeps the impractical 50% scale keyboard…BUT

It’s a 100% height Next!

(So you can only fit four in the space of a full sized next)

Inside’s not quite finished

Decided that VGA will have to go – for now

Continue reading “More Xberry Pi / Spectrum Next Mini!”

Third’s the charm! – more C64

Tad hungover on new years day, plenty of time to ruminate, so…decided to work on the last (which is the first!) of the keyboards…had a solid 4 or 5 hours to myself today so made a lot of progress!

Have finally made the C64Mini one in surface mount – Now i’ve sourced a supplier of suitable, well priced keyswitches, I’ve felt it worthwhile to re-visit this project…

What SMT means – Very little soldering needed for this prodcut. Just the Arduino pro-micro at this time.

I’m hoping this makes the kit much more accessible, many will put their hands up and state that the 600+ solder joins needed on the old one was ‘painful’….

Some pics!

Top of the board – based on the modified 4.1

Bottom of the board..

Next step is changing the schematic over to use the much more readily available Raspberry Pi Pico or even creating a dual footprint board so you select which microprocessor to use, either the 32u4/Arduino Pro Micro or the Raspberry Pi Pico.

Unsure how i’ll offer the kits, I may well just pre-solder the microprocessor on so it’s a truly plug and play kit!

Still have to route the board, which will take a couple of days.

Also have started re-designing the keycaps from scratch – the old CAD is nigh on impossible to manipulate due to being so complex (was my first complex CAD project after all), so it’s easier to start over – and…I’ve gotten this far after just a week or so of playing

Keycaps re-done – Just needs the lettering and symbols!

I’m hoping to get this finished in time to add to my batch order of Next Mini and Amiga mini prototypes

PCB’s finalised for Next Mini and A500Mini

Actual cash has been paid!

the 2000 custom switches are being sent to @jlcpcb, To use them all up, I’ve ordered 15 of the next mini keyboards to prototype

Front of the First prototype

Rear of the prototype

The rear of the Spectrum Next Mini keyboard has a Raspberry Pi Pico option – I’ll create a PRK keymap – this will allow people to use the device with USB ‘things’ like raspberry pi’s, PC’s or even the A500 Mini 😉

Without the Pico, it’ll work as a standard 5+8+2 next keyboard, or, for it’s main intended use – with the Xberry Pi’s 10×2 header.

Render of the prototype Spectrum Next Mini keyboard.

I’ve also ordered 10 of the A500 Mini Prototype – this one’s on version 10. it should be the final one before I can hit ‘production’ – everything fits, no reason why it won’t work. This revision just adds a little circuitry – which is easily bypassed if it doesn’t work

So, ETA – at some point in 2024!

Small Segue. Unofficial products! If Lego and Warhammer did a thing

Mini assembled!

All the pieces!

Purchased a few of these from the regular favourite websites!

Surprisingly well made and looks great on my desk.

For those not in the know , this is an unofficial Lego style minifigure.

It’s also a totally unofficial Warhammer 40,000 figure – I’m not really up with Lore but I think this is the White Scars.

All of $3.50 delivered, bargain.

Spectrum Next Mini Keyboard!

The Xberry Pi won’t fit in the Next Mini case ‘as-is’

So, I’ll do the east bit first and design up the keyboard to fit the Xberry pi’s headers.

This way, I’ll have a working next mini, just with a rather large raspberry pi shaped box next to it,

Kinda like a PC!

The easy EDA alignment of the keycaps for the switches to align the CAD
CAD aligned!
Next mini case is too small!
First run of aligned PCB

A500 Keycaps – ready for printing!

First iteration is now finished…there’s quite literally nothing left to do other than to slice and print…..then test fit, re-design and so-on

All the lighter beige keys!

and the Darker coloured keys

I’ve sliced these for my old school Anycubic Photon Mono – the original 2k one. It’s been super reliable. once tested, i’ll likley print these on the much larger Photon Mono-X – should be able to do 3 or 4 sets of lighter coloured keys at a time on that.

And the printers are all setup and ready to start too!…

Now to take the huge step of pouring some resin in, transferring the sliced files over and actually printing…..

Some other bits arrived for testing the new keycaps also! – it’s all happening (slooowly)…

New A500Mini keycaps – ready for prototype printing!

*any colour available as long as it’s beigey brown

Have spent the last week tweaking, adjusting…probably too much really. Likely i’m actually procrastinating about making this thing physical. The new stems and locking mechanisms are are all aligned and merged in with the keycaps!

There really ain’t too much left now on the keycaps. Some minor adjustments will be needed to the stem – It’s parametric – so I print, fit, adjust one parameter which changes all keycaps at the same time (unless something breaks) and re-print.

Have made final tweaks also to the main PCB – I’m on version 11 of revision 9 now!…Again, too many little tweaks here and there, I really must fire the printers up!

Till the next time!

Quick hack to align PCB and CAD

Quite chuffed with myself on this one

Alignment squiggles!

I’ve been tweaking away, adjusting the EDA (the PCB via EASYEDA) and the CAD (the keycaps via Fusion360)…There’s nearly 100 bits that need to line up for it to all go well.

Previously, with my C64mini kits design, i’ve broken out the vernier calipers , measured, tweaked, printed, measured, tweaked, printed…….until everything fits just right!

For the A500 Mini Amiga, the ‘about 43%’ scale means the keycaps are just too tiny to shove underneath my ‘go to’ 5.8mm x 5.8mm switches . In addition, soldering 60 odd switches, another 60 odd diodes, and the arduino is a tad arduous, so change was needed.
I’ve jumped to Surface mount style components

One advantage of Surface mount – Machine assembly – I’ll be buying in the boards mostly populated!.

The machines that assemble the boards use a file called a ‘pick and place’ file. Essentially a CSV file with co-ordinates!.

I had a ‘play’ with that CSV file, imported it into excel and plotted the co-ordinates

That looks suspiciously like a keyboard!

Imported them into Fusion as a Spline – The control points are the exact centre of where the keycaps are!

I just needed to align a point with one i’d already ensured was perfect in the CAD….and

The ESC key is perfectly located….

The centre of the stem of every key is perfectly aligned with every spline control point….Which comes directly off the Pick and place data of the PCB!

By overlaying the co-ordinates used to place the switches on the CAD model, I can now be very assured that the stems are located within the keycaps correctly, which are located within the keyboard…

or, in otherwords, it should all align, and hardly any 3D printing fake PCBS / jigs, samples, reworks needed…

Well, that’s the theory 😛

Lots of CAD work to do…A500Mini

Everything ‘fits’ – Lots of tweaking needed

I keep working with EASYEDA from JLCPCB as it’s just ‘easy’ and their PCB part has a great Export 3D model. For us metric types, just scale it by 0.254 and it fits like a glove. Very useful to align electronics and plastics in more complex models.

The new switches arrived

So, now to tweak the CAD to match the switches, make sure my resin printers are running, hand solder up a bunch of the sample switches onto an early revision keyboard, test and…

Keyboards! – Progress on the A500 Mini working keyboard.

Version 9 – Looks just like all the other ones 😛

Version 9 – Testing for interference fits – the support column is exactly underneath the RP2040 , D’oh!

Continue reading “Keyboards! – Progress on the A500 Mini working keyboard.”

More home Automation!

We had an LG Ducted Aircon system fitted in our Australian house back in 2015 – an LG B55AWY-7G6 I believe , a 15.1Kw Beast.

Well, turns out they take a lot of power…

And this is on a warmer day!

With Australian energy prices spiralling ever upwards… it gets expensive to run this. It draws just over 5kW…or, around $2.5o per hour to run during peak hours.

To make things more efficient, 3 zones were installed. Just hooked up to a 3 way electrical light switch, entirely manually controlled.

  • Zone 3 – the 4 bedrooms
  • Zone 1 – The main living area
  • Zone 2 – The Lounge / TV area

This isn’t enough zones – our ‘middle’ bedroom gets too hot – this is the outlet closest to the internal Aircon unit

The furthest bedroom doesn’t heat much at all – the furthest.

So, Enter Home Assistant

Normal people would call a professional and get an intelligent home climate control system installed (like This, or This) to take care of the ducts automatically.

That’d be too easy

I Purchased a couple of Zigbee relays

And grabbed a whole bunch of Zigbee Temperature and Humidity sensors

I found some cheap damper actuators which have an annoying RJ12 connection on them, they use internally a simple 50TKyj24-2.5-4700 AC Synchronous motor which has a ‘common’ and two other wires, one for driving clockwise, the other for driving anti clockwise

And, those RJ12’s are the reason for my Adaptor PCB. I need to feed 4 actuators with AC on either the red or the yellow lines, AND have the other side of the AC ‘common’ …it would quite a mess if it were all cabled up!

So, Thankyou to JLCPCB for having such a well priced PCB service.

The other PCB – is inspired by a number of people – https://github.com/Flameeyes/esphome-lg-pqrcuds0/tree/main

https://www.instructables.com/Hacking-an-LG-Ducted-Split-for-Home-Automation/

and the latest one – https://github.com/JanM321/esphome-lg-controller/tree/main

It just converts the LG controller’s protocol into MQTT so Home assistant can make it easy to integrate….Not much to write really, LG’s old wifi implementation (circa 2013/4) is pretty flakey nowadays, this ESP32 based local wifi connection should be much more stable.