C64Mini Keyboard – PCB Layout Success

After a loooong weekend and sneaking in a few hours – Success with the keyboard layout dimensions!

There’s few tweaks here and there remaining to align things perfectly and also to add some nice Silk Screen artwork

And, how I got there!

C64 Mini Keyboard mod – More Electronics Part II – OOPS

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….

 

Oops…

C64 Mini Keyboard mod – More Electronics

Looking a LOT better!

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

Whipping out the calipers again…….

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!

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

A quick bit of googling suggests that ‘Tactile Switches’ are what’s needed…..I’ve used these before on other projects,

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.

 

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…………….