C64 Mini Keyboard – Rev2 assembly

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 up
Finally 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!

Author: bleughbleugh

Early Fourties, Wife, two kids in primary school. Both of us work full time...3 years now Back in Blighty after a decade away...It's a new country for everyone! Still finding time to tinker!

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