Some quick steps right now – photos to follow.. Suggest have two tabs open, this one and the other PICTURES tab for reference
Some videos are up on youtube also
SUMMARY- SOLDER PARTS ONLY IN THIS ORDER
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
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
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
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!
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
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 .
Ok, first thoughts, it seems to work, abeit slowly and with making my hand a bit sore….
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.
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
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.
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
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’
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
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!
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……..
Just over a year ago I purchased my Creality Ender 3 Pro…an absoloute steal at about £140 after discounts and Topcashback special offer at the time.
I was having so much ‘fun’ with my Wanhao Duplicator 9 that I didn’t open the box for nearly 1/2 a year. and I only fired the thing up a few months ago!
I have to say, I’m impressed. The printer deserves its rabid fanbase following. It printed flawlessly out of the box without any setting up.
It’s surprising the difference having a reliable ‘work horse’ printer makes to the hobby. I need a bit – I just go print it. no faffing about with levelling and bed adhesion.
Till it doesn’t…….
Note, if your previously reliable printer seems to under-extrude, even on known great filament – try the extruder arm.
Something seemed ‘off’ when printing standard stuff – almost overnight the printer just seemed to under-extrude, not be reliable and, well, become more like my Wanhao D9 (a bit crap)
Even bizzarely, the printer would print OK over to the left, but under-extrude to the right. Took an hour to diagnose this! When the head was over to the right – it would pull the mechanism slightly which dislodged the arm enough to slip the filament.
Luckily, This extruder tech hasn’t moved in years…….An unassembled, missing parts kit I picked up off facebook a couple of years ago (syntek, sintek or something similar) which itself was a few years old had just the part..(which complete, looks identical to this Aliexpress one …..
Back a couple of years ago, I lucked out on a facebook marketplace post. Someone was selling an unassembled 3D printer kit, that was tatty and had missing parts………Woo!
I did a 30 mile detour on my voyage home from Wales and grabbed it. excitedly pulling all the bits out of the oversized, filthy box and….Putting them into a rather smaller, cleaner box for a couple of years whilst not doing much with it.
Well, today, that £40 investment paid off.
by hacking a chunk off the 8mm threaded rod, using a few bolts and washers, and a quick mod using a spare Hama-beads square that we had lying around, I was able to fix the broken hamster wheel!
or, in other words, I’ve massively over-engineered a fix by butchering a 3D printer (kit).
On the plus side, I’ve a happy hamster AND saved £2.87 by not needing to buy a new one!
Also, It’s gotten me thinking….HAMSTER STATISTICS.
Scroll down to 19884 – See just what processors are sitting in the same area – what their retail price was! – this processor sits at exactly the same position as the intel i7-10700KF
A 125W DESKTOP processor that costs £400 on its own on ebay right now. Add all the other stuff needed to make a fully functional PC and you’re getting close to a GRAND on a DESKTOP!
In summary – I’m besotted….This laptop’s happily rendering in REAL TIME what my old laptop took tens of minutes in Fusion360
if you’ve been holding off buying a laptop, you really can’t go wrong with the Renoir series of processors.
and, for games – seems to run Fortnight,Starcraft 2, and a few others just fine at maximum settings! performance apparently is about the same as the Geforce MX250 which isn’t sloppy considering this is integrated graphics and has just a 25W TDP when under extreme performance. The MX250 graphics card has a 25W TDP on its own for this benchmark!
Fawning over, normal service will resume shortly 🙂 – in the meanwhile, ask away any questions, happy to answer them
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!
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
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 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
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
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……….
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
I Purchased 10 controller boards with the SMT components ready assembled There’s a few small bugs……But, that’s what prototyping is for.
First major annoyance – I’d goofed and left VCC on the arduino as 3.3v in the schematic. so, the board wouldn’t power up inside a next. Quick fix is to short RAW – to the VCC pin on the Arduino
(RAW is a 5V OUTPUT when plugged into USB, or 5 and a bit Volts INPUT to power the Arduino)
This has the potential downside of back-powering the Next via USB via the 5V Line when it’s sitting inside a Next and someone uploads a sketch
Another change needed – The Arduino’s USB port fouls the case when fitted inside. With a USB cable in, the lower part of the keyboard inlay blocks the port. – it’s ‘just’ about bodgeable however if you really wedge it in there. But, not ideal So, i’ve tried with soldering the arduino ‘upside down’ on the wrong side of the board – that seems to work. The board’s mounted just far enough ‘up’ into the case that a USB cable can sit under it.
For the production version i’ll re-arrange the board completely
Another further change –
Removing the RAW pin entirely from the Arduino and shorting the Next 5V directly to the VCC pin on the Arduino
That’s about it for these pictures,
From top to bottom –
Original board – has a resistor bodged in and the RED led installed on the wrong side. Also has my ‘impossible to solder straight’ PCB fingers.
Third board – upside down mounted arduino with missing RAW pin
Second board – my ‘go to’ working one right now – also has the first run of my ‘quick fit’ connectors……i’ve done about 20 cycles of inserting now and they’re still working!
Due to my previous goof-up of having made the old LED insterts ‘backwards’, I designed new ones!
They’ve arrived and are all round much better
Slimmer – just 2.2mm wide
Here’s what they look like – the features are a bit too small for JLCPCB to handle on their mass production – their mill uses a 1mm bit – guidelines are minimum of 3mm between milled out slots
I’ve ordered 50 of these – should be plenty to fill up the 10 prototype control boards i’ve gotten made and leave a few over for experimentation / errors
There’s a small problem however with mousebites this small – each board takes a good five minutes or so of dremmeling to get ready!. I can do about 7 boards to a charge of my battery powered cutting tool….I’ve ordered 50 prototype PCB’s so that’s lots of minutes of work ahead! good thing we’ve a handful of N95 facemasks picked up from back in March just as the world went loopy!
Here they are in all their glory, powered up the RIGHT way round on a controller PCB.
I hand soldered all 4 of them using some new (expensive) solder paste,d 3 worked first time! the last one had two LED’s mis-aligned…Quite a good improvement!
Each insert so far on the prototype is taking easily 20 minutes from receipt of parts to working device. Each new controller PCB is taking over an hour of soldering and wire cutting for the quick contacts. That should come down quite a bit once i’ve figured out a process.
Yeah, spot the mistake 😛 Still, quite chuffed – these are powered up and working INSIDE the next! –
There’s no control YET – this is just a single routine that runs upon powerup in the Arduino….
And, just as a final superb moment – look at these results of a quick i2c Scan (there’s a lot of numbers due to using an HDMI monitor)….That 3rd Device at address 0x45 – That’s the Spectrum Next Super LED Blinkenator 2000 just waiting for a .DOT command to control it 🙂
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…..
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!
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
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
to use some PCB grounding spring contacts to provide a quick fit connection didn’t really pan out – the contacts simply didn’t solder on easily, too difficult to align correctly and quite weak – I tore a few pads off trying to get them aligned and correctly ‘grippy’ on the insert.
multiply that by 16 each board – the first one took me about 2 hours to get to be in an ‘ok’ state – Not really acceptable for a mass production product – not that this’ll be mass production but I’d rather not spend half a day on each of these getting them ready for sale……..
The second slight issue – See the photo below
The PCB is laid out on top the next board in the position it’ll be installed in.
There’s a prize for someone that spots the goof-up
Have a further look at the PCB powered up………..
Yeah, I got the inserts ‘back to front’ – That’s the result of working on a bottom mount PCB from the bottom…….
There’s two ways I can fix this
Simply rotate each LED by 180 degrees on the PCB and install a bodge wire to swap the input and outputs around………
I can simply re-design the LED insert and improve upon it!
a few reasons to re-design,
The first 6 LED version still has a bit of point brightness – I fear that even with the SLA printed inserts it won’t be diffuse enough..
8 LED’s – This should spread out the light more, reducing the hotspots a bit
0.4mm Slimmer – this lowers the LED’s further into the case, allowing much more plastic to sit above. I’m hoping this will de-focus the light more
Reversed connections to match the reversed controller board!. reversed is the new non-reversed now 🙂
New insert PCB’s are on order and should be here in a couple of weeks, I’ve bitten the bullet and ordered FIFTY….Also a few hundred more LED’s and a large tube of solderpaste.
Doing these first 10 dev boards is going to be fun – 320 1.5mm LED’s to be hand soldered!
The Controller board fits inside the case almost perfectly
I’ve slightly offset the J15 connector on my PCB to the one on the next. This offset gives a lot of friction, but needs some long term testing – the standard header I installed on one of my boards seems to work well as a friction fit. BUT, i’m not convinced that 32 LED’s, each pulling 5-20mA, (depending on which datasheet I refer to) – or between 160-800mA total depending on how I end up setting the brightness…..800mA is a LOT to pull
I’ve purchased a new gadget – A Riden RD6006 Benchtop ‘power supply’ so once i’m set up, i’ll charaterise the LED’s and current draw to set the software limits appropriatley
I doubt i’ll take nearly an amp on this board 😛
One further small mistake on the dev board –
When originally designing this controller board, I was to use a 3.3v Arduino to make it compatible with the Next’s 3v3 i2c.
For a few reasons, I’ve changed to using a 5V arduino and putting on-board a level translator device – this gives a 5V buffered i2c output that anyone can easily plug into
I forgot to change the net names….The board still ‘thinks’ the Arduino is either powered from RAW (it’s ‘unregulated input’) or 3V3 VCC…
The RAW input drops a few volts through a voltage regulator on the arduino to give the arduino a nice regulated 5V.
The next output is 5V….it’s not enough to power the Arduino through the RAW pin…
Took me quite a while – and a bit of soldering hackery to figure that one out as the speccy picked the board up perfectly when patch wired in place..
USB powered, it works perfectly
in the Next it doesnt….
The fix – I think I can just short the RAW pin to the unconnected VCC pin on this first batch –
See that i2c device, found at address 0x45………..That’s the Blinkenlight 2000 PCB :-), alive and inside the Next!!!
Had a little bit of a play with the daughterboard to see if there’s any possibility of putting a ‘push push’ SD card inside…
Unfortunately it isn’t without chopping at a couple of supports inside. I’m trying to keep my Next case fairly minty – untill it’s possible to get another, i’m going to avoid this mod.
The reasons it won’t fit – The case was designed with two ‘helper’ guide rails for the SD card – shown in yellow in the images above. Those rails stop any push-push mechanisms from working – there’s just not enough mounting depth for the card reader.
Now, if someone were prepared to snip those rails off….then it’s entirely possible to knock up a new daughterboard……I’ve already done most of the EDA before I thought to take the next apart and check 🙂