C64 Mini Keyboard – More!

img_3245-1C64 MINI KEYBOARD SCHEMATIC 1Small updates –

Slowly but surely –

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Spectrum Next – A little distraction – Push Push SD card?

specnext PCB PUSH PUSH 2

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 🙂

C64 Mini Keyboard, 1/2 alive and Some CAD

Bit of a change of pace from the electronics, onto the CAD…Here’s a first draft of the first key on the C64 Keyboard – the Left Arrow!

Done at full scale, then at 50% scale

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C64 Mini Keyboard – Some progress!

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

 

C64Mini Keyboard – PCB Layout Success

C64Mini - Final PCB Revision Maybe

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!

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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…

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C64 Mini Keyboard mod – More Electronics

Thru Hole Keyboard PCB - First spin
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……. Continue reading “C64 Mini Keyboard mod – More Electronics”