I just bought an old Apple Extended Keyboard II made in Ireland in the 1989.
I want to upgrade it to a new level with a new microcontroller and a programmable firmware, I painted the pcb (thank God they didn't know double sided technology back then) and I want to wire it to a little arduino.
The fact is, this keyboard is advertised as full N-rolling rollover. But my calculations shows a 16x8 matrix + 10 dedicated keys (-32 unused path crosses) and only a handful of diodes. I can't count them since they are behind a metallic shell, but they can't be more than say 20.
Is that possible to rolling 106 keys simultaneously with only that many diodes? I think not, but I may be wrong (I'm not an electronic engineer).
So I though I could cut the tracks and add plenty of diodes (maybe even LEDs for the win).
Rewiring the microcontroller is gonna be tough, but I think most of the pins could remain in place, besides the arduino micro is much smaller than the apple chip. Furthermore I want to switch the latch/4to16 decoder with a modern i/o expander (or maybe even a daisy chain of registers for the lulz).
To mantain the vintage look I have to find a way to transform that sassy ADB to a disguised USB.
What do you think? I have zero experience with this.
Some key are easy to clean, other, like the fancy 'K' have scratches that needs some more work.
Here you can see the adb connector
The arduino micro fits just fine
I deliberately painted the tracks that connect the keys, in case I want to rewire them directly to the microcontroller. I'm also thinking about connecting all the 106 keys to individual pins of daisy chained expanders.