Have been promising a long time to do this, so finally took a few hours to butcher another mini!
Some views are excellentAnother great view And the worst view
As you can see, for the most part, it’s pretty good, but NOT perfect
what I’ve discovered…..
2 part epoxy works best
Each keycap row is a different depth – the top one needs the least glue, row 3 the most
My errors here. I used a hard plastic glue from Bostick. it doesn’t grip well enough on the top of the keyswitches. I glued everything, waited a few hours, half the keycaps didn’t stick
glued the rest, waited, half again didnt’ stick…rinse and repeat about 6 times, adding more glue till finally they all stuck.
The 2 part epoxy stuck fast and hard! – but I used too much.
The repeated adding of more glue caused the multiple key levels you can see in the picture
Postage on most was actually slightly cheaper than last time! But the two heaviest ones were more, the largest one was quite a bit more than anticipated…so it all averaged out ok…
One repeat customer has a couple of freebies, only one assembled this time!
Also my first ever customer finally will have a spare kit and some stuff to practice with 🙂
Next small batch is coming as soon as the 20cm USB cables arrive.
If you want a kit without the short, tidy looking USB cables then shout and I’ll do a small discount 🙂
Correct orientation of the switchesCorrect orientation from the top. (Except the shift lock…oops! That’s why I put extra switches in :-p)
A funny story about multi sourcing components and the importance of testing before shipping!
I used a supplier on Aliexpress to purchase a few thousand switches in a few orders over a few months but their prices went up quite drastically after the last order (doubled!!) they weren’t the cheapest to start with but were reliable and friendly, worth the extra ££
I found another supplier who did a good deal for a full bag of 4000! Ordered them and waited, very quick delivery and friendly also (will buy again!)
I built my first test new keyboard with the new PCB and switches
It didn’t work. Well, actually, it did! Work perfectly…but in reverse :-p …..
If you mashed every key simultaneously then only released the key you want to press….it worked!! Yeah, the supplier sent me 4000 ‘inverted’ switches! My fault for not checking prior to ordering, they ‘look the same’ so ‘must be the same’ was a wrong assumption on my part! (At least they all weren’t the shift lock type!!)
It’s a VERY easy fix though (found after several panicked hours of testing and building Keyboards)…rotate the switch 180 degrees and it’s perfect!
In each kit I’ve included a small errata note and list of basic instructions to help. It’s an annoyance but for you guys it really just means the silk screen doesn’t quite match the switch orientation so just ask first. Look at the pictures and of any doubt, email/messenger/twitter/Reddit me 🙂
Cut one leg shorter on the diodes – Use scissors . About 1-1.5cm is good
bend the short leg side to a right angle
Note the orientation of the diode – The F Key diodes have a diode picture on them. The white bar matches the location of the black bar on the diode.
put diode in holes and bend slightly to lock in
repeat for all diodes
Solder all diodes
clip the excess legs back
you have a few spare diodes so don’t be afraid to experiment on one or two to get the right bend / fit
ARDUINO HEADERS
Probably best to solder these in now before you forget
I’ve found it useful to PLACE the arduino on the headers (DO NOT SOLDER YET) so it keeps the headers parallel
Make sure the black part of the headers is on the underside of the PCB
Solder one pin of each header
remove arduino
finish soldering
SWITCHES – STEP 1, JUST TACKING IN PLACE
Pay attention to orientation
don’t worry about straightening the switches at this stage, the goal is to just ‘tack’ them in with a single solder blob to hold them in place. They can be wonky, it doesn’t matter.
DO NOT SOLDER MORE THAN 1 PIN OF EACH SWITCH IN ONE GO
The switches are easily heat damaged – they become ‘sticky’ and no longer move smoothly if the plastic is melted due to excessive heat. During the entire soldering procedure for the switches, do ONE leg, move to the next switch. when all are done, move back to the first switch and repeat.
I’ve damaged only 2 switches this way soldering the prototypes but it can happen if you’re not careful
Note that the white part of each switch is asymetrical. One side has a ‘dip’ / inset which guides the switch up and down. the other side is smooth
there’s a marking on the PCB to represent this dip / inset.
ALL switches go the same way
Get a sheet of paper
Insert the top row of switches into the PCB
Place PCB on sheet of paper and fold paper over the top, tightly
flip the PCB over
hopefully all the switches stay in place
Solder just ONE leg of each switch – any one – say the top right
Repeat for Row 2
DO NOT FORGET TO SOLDER THE ARDUINO HEADERS IN PLACE
Repeat for Row 3
DO NOT FORGET TO SOLDER THE ARDUINO HEADERS IN PLACE
Repeat for for row 4
(Hopefully you didn’t forget to solder the Arduino headers in place?)
and finally the space bar
SWITCHES – STEP 2, Straightening
This is probably the most important step to getting a good looking keyboard with all the switches aligned. Spend some time getting this right, you have a handful of ‘spare’ switches so now’s the time to make mistakes and fix them whilst there’s only a single solder blob on them
I’ll post a few videos shortly but there’s a technique.
Hold the board in the air
Use your index finger to push in, and slightly down on each switch whilst soldering the previous blob. The goal is to move the whole switch slightly so that it’s slightly at the top, or the bottom of its footprint.
when you melt the solder whilst pushing in and down, the switch will move slightly, sometimes you’ll hear a little click or snap as the solder melts
repeat this for each switch, pushing in and down slightly – when you look at the final position, there’ll be some of the pad visible at the top of each switch
NOW IS THE TIME TO TEST EACH SWITCH FOR SMOOTH MOVEMENT
of the 5 keyboards i’ve soldered, I’ve had two defective switches, this is partly the reason why there’s a few extras in the kit
of the 5 keyboards i’ve soldered, I’ve broken 3 switches by either over-heating, or trying to remove after putting them in backwards. unless you’ve got a hot air gun, they’re tricky to remove intact, hence check NOW whilst there’s only one solder blob!
When you get close to one side of the keyboard, you’ll have to fiddle a bit to keep pushing the switches in the same direction. I’ve found that changing technique a little and ‘flip’ the board lengthwise works. hold the board against yourself and use your thumb to pull the switch down instead of push
repeat the alignment technique for ALL switches!
SWITCHES – STEP 3, Final soldering
This is the easy / relaxing bit!
DO NOT SOLDER MORE THAN ONE LEG OF EACH SWITCH AT A TIME
do it by rows, clusters, however works for you, but here’s what worked for me
Solder ONE pad of each switch, then move to the next
once all switches are done, start from the beginning
Solder another pad, etc etc
A SMALL CHEAT – You only actually need to solder 3 points. Two on the ‘bottom’ of the switch – these are the electrical contacts. ONE on the ‘top’ – this is for mechanical stability. As you look at the keyboard, the bottom two pins are the important electrical ones. Pick any on the top
on my prototype, I found soldering all 6 pins tiring, so on my second version I just soldered 3 and it worked perfect. Up to you, but DONT SOLDER MORE THAN 1 PIN AT A TIME
Arduino
Note the orientation of the Arduino by the Small USB socket and a mark on the PCB. Also the silk screen on the PCB will match the letters on the Arduino.
these need a little more heat to solder to the pins
BEFORE this point (or, worst case, at this point) I’d highly recommend you clean the keyboard thoroughly and go, purchase some clearcote / clear lacquer. I haven’t done it yet but will be spraying my next keyboard to get some longevity on the text and paint……...
The mould’s quite bubbly and not really useful for much other than being a support…But, if done with more care – who knows!, Maybe C64Mini Chocolate keyboards?
Next step, Power Tools!
ROUND 1
Mwahahahaha!
Still not entirely sure if it’s even possible to quickly and repeatedly butcher the C64Mini’s keyboard reliably with good quality.
For doing your own / one off’s, this step, you can take as long as you want. if you plan on doing a few though, taking a day or two individually dremmeling out the keys isn’t my idea of fun.
I do have a CNC – so, worst case I’ll have to learn how to actually use it, then I’d just need to make a protective jig, sit the keyboard on and just CNC the keys out. I’m not really in the mood to spend a few weekends firing that workflow up yet
Failure
The Angle grinder wasn’t really a success…..The blade’s too small and the sanding is going to be too uneven. There’s no way this will work .
Round 2………..
Larger surface area = larger chance of evenness?Too much vibration
Ok, first thoughts, it seems to work, abeit slowly and with making my hand a bit sore….
new sandpaper should do it
At this point, I figured if I use something soft and large, I could hold the keyboard in place and sand it without hurting my hands so much…..
Puzzled over this one for quite a while till I looked down……..
Found an incredibly inefficient lawn cutting method! – Orbital sanding
Seems to have done the trick!…Pressing down into the grass holds the keyboard in place and also helps resist the vibration of the sander, making it sand more efficiently…………Win Win….Also i’ll patent pend using oribital sanders for domestic grass management.
But……
Poor Lawn
I moved to another bit of the lawn to avoid totally destroying a good bit of the grass…….I found that sanding till you can see the blacks of its eyes…….the lines between the keys seems to work well. At this step, you’ll want to remove as much material as possible to avoid so much processing / sanding later on
Do resist the urge to twist / remove the keys, try to let them come out almost by themselves
oops
At this point I’d realised that an average household lawn is actually quite abrasive..Have a look at the whiteness of the edges of the keys!
Oops! – ah well, this is why i’m experimenting, so you don’t have to. I’m going to run with the theme though -these keys look a bit battle worn now, no going back so i’ll probably add a similar theme to my C64mini case 🙂 will be good to relive the old days of creating scenery and my Warhammer 40,000 airbrushing . never really did play it, just enjoyed hacking up the plastics……..Anyways…
Keep sanding, get as much material off as you can (it will save a LOT of time later)
Once you’ve got them all separated, make sure to lay them all out in order so you can admire all the keyboardy keycappy goodness that’s resulted from the dismemberment of an innocent miniature recreation of an 80’s 8 bit home computer.
Eeeeeeeeeeeeeeeeeeeee
Now, go spending several hours in the garden trying to find the most commonly used letter in the English alphabet!
I’d neglected to factor in the ability of these tiny keycaps to fling themselves a considerable distance in various directions whilst being vibrated several hundred times per second.
Suffice to say, if you’re doing the same thing, try to do it in a location where the floors relatively clean and uncluttered
A colourblind person trying to find a brown keycap in a green lawn that’s not too long, but just long enough to expose the also brown ground beneath……..Yeah, not fun.
After an HOUR of searching though………………..Eeeeeeee….A full keyboard
full c64 mini keyboard keycaps!
Next step – post processing. Removing supports.
This step i’d say is the most important. Sand down a bit the bottom and curves of each key. Get rid of all the burrs, bits, etc. you won’t get much of a chance to do this once they’re stuck. Spend a lot of time on this, cleaning each key, just getting it ‘right’
Mini Mould All filled
Once your keys are all looking great and sanded, smooth – arrange them again into a the keyboard layout. Then, one by one, transfer them into the mould.
you’ll wanna make sure you get this part right 😛
I did them line by line, starting left to right. I also had taken a picture of the keyboard prior to refer to. Check twice, place once……………
Now i’ve realised that I haven’t actually considered how to stick these things in! – i’ll need to go research glue, D’oh! gotta pause this for another week of research and buying bits
Time’s progressing and it’s still taking a long time to obtain a satisfactory print of my CAD keycaps. Some quotes have come in and…they’re quite a bit.
so, time to change focus for the short term to let me actually play games on the mini with all the keyboardy goodness that a working keyboard will allow
So, on to some butchering
The Plan….create a plaster of paris negative of the original keyboard – to hold the keys straight when attaching them.
Step 1 – Print out the case design from my last post
Fits like a glove……..or does it?
Step 2 – realise that I’m making a NEGATIVE and the keyboard needs to sit INSIDE the box, ‘upside down’ Redesign and re-print…
Better
Step 3 – Coat liberally in spray oil… Wife wasn’t too happy that I’d used her pricey artisnal olive oil from our trip to Italy, nothing but the best for my Mini though………
Step 4 – Knock up a batch of pancake batter Plaster of paris…About 50 grams of powder and 60ml water worked for mine….not too viscous.
fill the keyboard case just over 1/2 way to measure what you need
Step 5 – Fill up the mould
Screw on the keyboard – making sure the keys are aligned and straight with the F Keys and wait overnight…
Use the holes either side to top up the plaster so it overflows a little
Give the whole combo a dozen or so short sharp drops / knocks on the table to free up any air bubbles
Did an attempt at a jig to make hacking up your own keyboard just a little easier….
it’s fairly easy to hack up the existing keyboard into bits….(get hacky thingy, cutty thingy, hack, cut…maybe smooth off burrs if you’re feeling artsy)
Getting the brand new hacked up bits of plastic that once looked like a keyboard to sit straight on the switches and resemble the previous keyboard resemblance …..not so much.
Turns out that making things ‘straight’ is hard……..so, some ideas
3D design and print new keycaps with locking mechanisms that work with my chosen keyswitches (still onging, it’s been MONTHS of work)
My first other idea…….. create a form to fill with plaster of paris, press the plastic full keyboard into that form, leave to set…
Remove keyboard and admire a perfect negative image of the keyboard.
Two things that could be done with this
Use that plaster of paris as a form to create resin keycaps (without any lettering) – I’m working on that!
second – it can be used as a perfect ‘form’ to sit the newly butchered keycaps in, fill with epoxy glue, sit keyboard PCB on top and let the keycaps become glued on, all nice and straight like!
it’s fairly easy to export the keyboard PCB outline from EasyEDA as a DXF then import to Fusion, extrude and…voila!
But…There’s an ever so tiny mistake in the image above
That’s the printed version…The holes line up great!
But….
Yeah, the keyboard should be face down!, D’oh!
i’ll see if the snips’ll work
The other thing….
Fits like a glove….
Nice and snug – Note the top row of keys is level…..
Some small design work needed but the idea has promise!. I just need to re-jig the hole widths a little to accommodate the angle of the keyboard better!
I’ve purchased another couple of C64 Minis so that I can improve this jig more. I’m not quite certain where the keys will ‘fall’ once they’re seperated from the base of the plastic moulding.
The more I think about it, i’m thinking that there could be a shedload more work in this jig – one ‘saving grace’ though – due to the way injection moulding works – there’s a slight taper on the existing fake switches. And, I suspect that the rear of them has been modded so that they’re almost perpendicular to the base. this will help the whole mould ‘pop off’ the injection machine…
That also helps me with this jig as it really means that, at the base of the keys, all the keys seem to have the same uniform rear rising, almost perpendicular taper and front curving taper. kinda like the below diagram
That could turn the whole change into just re-extruding the jig key holes at the 8 degree angle of the keyboard as above……..
It’s taking way too long, but I think I now have the lettering ‘just right’ – at least on the screen.
This was printed a bit too hastily at 0.08mm layer height on an Ender 3 printer. I’d used a brand new roll of untested filament and didn’t bother changing any settings. – it’s dimensionally ‘spot on’..
I’ve purchased a 0.2mm nozzle for my next trial , it’ll take ages but i’m hoping that those fine details on the characters come out a little better.
Why it’s taking so long……..
I’m learning as I go. I’m ‘tracing’ letters i’m finding on the net, creating them as a new sketch along the whole rows. There’s 4 differently angled rows so each needs to be extruded in a different direction to ‘cut’ the key.
This first run matches the C64 keyboard font as close as I can get. I’ll then ‘archive’ this layout for future use and create a second ‘3D print’ version.
This version will forgo the accuracy of the font and make features much wider, more rounded to allow the characters to come out better once 3D printed. The complex ones like ‘run stop’ won’t ever come out great on a standard filament printer, but the letters already come out pretty good…that’s a win for me!
a full keyboard!
The full keyboard is above – and you can see part of one of the adaptors i’m designing to click them onto the keyswitches. each keycap is hollow. that small grey part will sit inside the keycap
Where the time’s being spent…..
And finally – part of what’s taking so long.
Each key/character is taking on average about 1/2 an hour to an hour to design. Lets say 45 minutes.
65 keys to label
That’s a LOT of minutes…and i’m only getting an hour or two every few nights – a good solid weekend ‘free’ would be great and have this sorted.
On top of that labelling (which is now finished) I have to try to make each letter more legible and easier to 3D print. Generally that means ‘bevels’ everywhere – you can see above that i’ve done ‘Run Stop’ and ‘Shift Lock’ but SHIFT is still to do….it’s not as easy either as ‘copy, paste’ the Shift from Shift lock – that’s a different sized font on a different sketch plane.
Just one example of the issues I’m seeing…The Letter B
The Letter B – trying to create a fillet – rounding off the edges
The Letter B above has an issue with the geometry – just by the 0.1 – there’s a part internally up towards the arrow that shouldn’t be there – that’ll could play havoc with a slicer when set to really small layer heights
B – Alternate view
But, the Fillet also creates a zero thickness surface which looks unsightly and will probably cause issues if I don’t correct it now
So, Back to the sketch
Letter B – The Sketch
As you can see, i’ve kept the characters with few (if any) constraints. this way has been easier to freehand and eyeball as I can drag stuff around till it looks right by ‘locking and unlocking’ lines. most constraints used to create right angles, etc have been removed after to help with the process of making it 3D
Anyways, the ‘issue’ with the fillet seems to be around the place where the two control point splines meet – i’ve highlighted one in blue above.
I re-coincide each spline (have found deleting and un-deleting works, as well as hitting coincident )
That change should hopefully roll back up the timeline to allow me to make the fillet work.
To Create the key lettering I the character by 1mm elsewhere in my workspace, then move it to over the key.
Then extrude the face of the character into the key and ‘cut’ ….
this may seem odd, but it’s a really quick and easy way of consistently creating cutouts on a row of keys and making quick changes later.
That didn’t work, so, jump into surface mode – delete the entire inner arc of the B. Re-create the arc as a ‘patch’. Stitch together the lower part of the B. Then stich the whole keycap, then re-apply fillet and…..Voila…..3/4 an hour later, one filleted B…And a learned workflow if the same thing happens on another key!
Note, as-is, the keyboard fonts are a bit innacurate. I’ve sized everything based upon the smallest characters that need to fit – i.e. run stop, etc. The individual letters could be bigger – but any bigger and they’d look too big compared to those……….
Next steps,
DFM – Design for manufacture.
Just because you design a 3x2mm hole, doesn’t mean it’ll print at 3×2. Generally Filament printers do outer perimeters a little larger, inner perimeters a little smaller. The first few tests i’ve done now prove this. so, After a few months of ‘out of the box working’ on my Ender, I’ve finally gotta bite the bullet and calibrate it. The plan is to create an offset in the CAD file so that I still design the holes accurately based on measurement, BUT, can add a accurate ‘calibration figure’ Fudge figure to make them a little larger or smaller as necessary.
Right now my Printer is doing slightly oval prints – which should be easy enough to sort out if my D9 Adventures were anything to go by
Lovely and sunny outside. I’m in the conservatory kinda enjoying the outside………Through Hole Diodes should make for an easier assembling kit
My Kids hate me, my wife’s lonely but the march towards C64-Mini Keyboard workery continues – That and they let me have a few hours to tinker on the weekend!
Figured whilst assembling the new boards, I’d see just how long it takes to solder them….
Quite a while as it turns out
1/2 hour to solder in 65 through hole diodes
1 hour to solder 67 switches
another 1/2 hour testing and programming
So, about all up, we’re probably talking 2.5 hours for me to fully assemble one of these…….
Except, that 1/2 hour of testing and programming actually turned into a 5 hour ‘session’ of bug fixing / fault finding – one of which…..
One of these is not like the other………..
A back to front key causing lots of characters to repeat accross the screen…..M, Space – which are both on the same column of the matrix too!
Fixed that and have discovered that it’s not really possible to re-use the switches once you’ve soldered them in – UNLESS you use a hot air gun to remove them. I’ll definitley include a few ‘spares’ in each kit
The next problem – A sticky, grindy P key – I lifted a pad removing it , fortunately, the pad wasn’t electrically connected – only 2 actually are – which will save you some time! – just solder 3 holes for each switch – that’s 201 solder connections for switches instead of 402!
The next problem…the Fantastic QMK Just refused to work and compile 😦
Kept getting “qmk avrdude.exe: butterfly_recv(): programmer is not responding” the thing just wouldn’t work over USB like the others had
which turned out to be a couple of things.
You can’t use AVRDude when the Arduino IDE is open…
Arduino Leonardo type devices (well, the clones anyway) can be a bit finiky with the USB…
Generally sending them a ‘blink’ sketch does the job…BUT, they very often need a quick ‘double tap’ reset pin to ground whilst uploading……..that’s why I have a RESET header on this board – if you want to solder one in, feel free, it’s mainly to help me when developing it.
Another issue was the frequency setting in the rules.mk file – I’d previously used a 5V Arduino pro Micro (Atmega 32u4) , somehow a 3.3v one had snuck into my spares box – these run at 8MHz, not 16MHz
Changed the firmware, recompiled and……..It’s alive!
First row lined up – second just tacked on with a single joint, ready for lining upFinally added a bit of heat shrink
Straight!, got the technique sorted – Note the two that are slightly ‘off’ to demonstrate what happens when you change the way you ‘hold’ the switches when flipping the PCB to solder
The case fits the keyboard like a glove!
Also got a bit of a chance to progress with the CAD……
This one day may turn out to look like pretty rough keycaps! mini ones! for a mini computer!
Now waiting on enough Arduino Pro micros and switches to start making kits up!
Each DIY kit will probably contain the following – i’ll firm up with pictures once i’m done test populating a rev2 board
70 Standard switches
70 Diodes – Through hole (possible SMT option also depending on price)
1 USB Hub
1 PCB – Rev 2 or later
1 USB cable
two small pieces of heatshrink tubing
a couple of pieces of wire
1 Arduino Pro micro – Pre-programmed with QMK firmware and custom Keymaps
Some instructions
a set of FDM – Filament printed keyswitches – These probably won’t be ‘perfect’ so i’ll be chucking them in as effective freebies as I won’t be releasing the keycaps as a digital file.
About that last part – I’ve spent countless hours on creating these keycaps, and still have more to go. I’ll eventually release them as a Digital file, but for now, you’ll be able to at least use the freebies to see if new keycaps are for you.
If you wanted a professionally printed set, i’ll be arranging something with a printing bureau somehow… It’s also likely i’ll be able to source reasonably costed SLA resin prints of these…watch this space
And for the money shots…….I’ve finished the top row of key text!
Now I’ve gotten the first row done, the next three should be significantly quicker.
The text is recessed into the key by about 0.4-0.6mm – between 2 and 6 layers of 3D print, not really enough to be clearly felt – but enough to be ‘seen’
After that, there’s the optimisation for printing – Filleting the edges – trialling depths and generally finding out what actually works, looks and feels good
Not much of an update, I put a shorter USB cable inside so thought I’d take some pictures of the top of the USB cable wiring…..
I’ve not installed heatshrink yet on the sticky-outy USB Pins – this WILL be needed to provide strain relief – being truthful, I hadn’t expected it to work first time so didn’t bother 🙂
Spent a few hours this week adding an internal USB Hub, getting ready to start on a basic instruction sheet for the kits
As can be seen – you can’t see it’s modded externally (well, other than the keyboard). Both external USB ports still work and internally there’s a free USB port for a USB Stick 🙂
After couple of weeks of work, I’ve finally cracked surface modelling with Fusion360 (a bit)
Here’s a bit of a step by step in creating your very own f1 Key! This is a very brief summary of what I should have done if starting from scratch, I’ve left out the trials, errors and headbanging……….
Not much really – Shift Lock keys just arrived off the slow boat. The pinouts are confirmed, I’m going to hit ‘go’ to manufacture after another quick check on the PCB
Also, from a bit of researching, i’m not so sure the Diodes are needed.
I may have to make two batches of board, one with, one without
After spending a while lining up the buttons and generally making the PCB layout a bit tidy, I figured I’d print a 1:1 and see just how well it aligns….
After a few days, I’ve now got something workable – The switches being Thru-hole allow ease of routing on both the top and the bottom layers. I’ve named each switch and diode with the keyboard’s actual Symbol to make placing them on the PCB much easier. you’re seeing the results of a few days work (maybe about 4 hours all up) of starting from scratch on the design.
Next step will be aligning the PCB layout and spacing with the plastic buttons
I’ve done what I can based upon rough assumptions above – the top row of switches for example – its row of buttons ‘just’ fits within my calipers – so it’s about 151mm wide
As mentioned before, there’s loads of ‘keyboard matrix’ tutorials out there, so, i’m going to not bother with any of those yet and work backwards a bit.
IF i’m making a micro C64 Keyboard for a mini C64, I mayaswell make the thing backwards compatible so that it could be used on a real C64…
The Shift Lock key looks a bit ‘odd’ as it just parallels up with the shift key.
I’ve thrown in some Debounce diodes also – because all the top mechanical keyboards have it, so why can’t I (no idea if this is a good idea yet, but easily removed before I get a PCB finalised) I’m not too worried about the Arduino bits yet – i’ll bolt on the decoding circuitry later – this is still just an excercise to see if it’s possible!
This isn’t the first version – The pic shows the newest footprint before I figured out the issue below
After creating my own custom SMT switch footprint / component and arranging the parts on the board – I hit a few snags – Have a look at the layout below…. you’ll see that the SMT legs just stick too far out
Easy enough, rotate every other switch so some are ‘up / down’ , some are ‘left / right’ with the pads.
That does fit – just, BUT, i’m going to have to cut a leg off 5 or more switches to stop them mechanically fouling and electrically shorting!……D’oh!, Possibly back to the drawing board with the switch choice?
The diodes i’ve chosen (for now) are a larger SOD123 package, about 2.6 x 1.5mm or so…one of the larger packages and I just happen to have a few in the shed (somewhere!)
The row of connectors on the right is just a generic 2.54mm space 20 way header. This’ll probably not be populated in my ‘final’ version that sits inside the Mini, BUT, i’ll leave the pads on the PCB so it could be turned into a genuine working C64 Keyboard 🙂
Small updates –
