C64 Mini Keyboard Mod – The Electronics

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 C64 Matrix…………(image pinched from THIS PAGE) 



This it’s quite quick to knock this up in EasyEDA

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!

C64 PCB Matrix

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 🙂

C64 Mini Kebyboard Mod – Switches

Tactile Buttons Google

A quick bit of googling suggests that ‘Tactile Switches’ are what’s needed…..I’ve used these before on other projects, Continue reading “C64 Mini Kebyboard Mod – Switches”

C64Mini – Keyboard Mod

The Bottom Side of the C64 Mini Keyboard

There’s Plenty of Volume – But what switches can be used to put inside the keyboard?

I’m not too worried about the electronics  side right now, there’s plenty of Arduino keyboard emulator tutorials out there.


Continue reading “C64Mini – Keyboard Mod”

C64Mini – Quiet but still Tinkering…Keyboard Mod

Some time back I purchased a Lovely little Commodore Retro item – A C64 Mini


Borrowed off the Retro Games website – The C64 Mini


It’s a TINY C64…….With a non-functional, cosmetic appearances only keyboard 😦

Lets fix that…………….

Continue reading “C64Mini – Quiet but still Tinkering…Keyboard Mod”

Finally – A Fully Parametric Transmission Line….

1 - Final Parametric - 1

Doesn’t look like much but this is the culmination of several days of cursing & Learning!

This enclosure (pictured sideways here) dynamically changes its height and depth depending on the speaker SD and the enclosure width you chose.

You can alter the following parameters , I’ve set the above to be the number in Brackets for my PS95-8.

Continue reading “Finally – A Fully Parametric Transmission Line….”

More parametric stuff – another design

I decided to create another grid and try some  alternate ‘maze’ waveguide ideas to see if I can optimise the path…….I think I have!

The grid is made of formulas – waveguide height and wall width and entirely construction lines.

To create the purple ‘walls’ it’s easy enough to drag the mouse, highlighting the required walls and press ‘X’ twice to toggle construction lines on / off

Speaker Parametric 9

Some experimenting with sizes eventually gives a waveguide length of 770mm near enough…..so I can fairly easily tune this enclosure by changing the position of the hole on the rear and blocking the last part of the line.

  • 106.588
  • 79.941
  • 26.647
  • 106.588
  • 133.235
  • 26.647
  • 133.325
  • 26.647
  • 133.25

= 771, near enough to the 720mm that I want!

I now have an enclosure that’s 170mm tall by 200mm deep by 190mm wide. 6.4 Liters. Can’t see really how I can reduce the outer size by much more than this…..