2023-06-05 (M) KeyBoardolier IO expander wiring

I grabbed an 8-conductor wire bundle and took a length that could reach from the IO expander to the far side of the keyboard, plus some extra for wire bending allowances. When I knew approximately where it would lie, I put some protective shrink tube around the bundle and fed it through one of the holes I drilled through the aluminum support. I trimmed the wires closest to the center, then stripped and tinned each column. I applied a shrink tube segment to each joint to isolate it from the frame.

I repeated the process on the other side, which had seven columns, where I repeated the wire order according to color. I trimmed the fifteen wires and terminated them on the IO expander. I connected the five rows with another bundle of wires through the central support, then ran more conductors to the microcontroller's digital IO pins.

In retrospect, I should have used an IO expander on the first side to avoid running eight wires. When I connected the microcontroller and LED cluster, I saw they did not rely on the same voltage, so I may have to add a booster and level shifter.
Switch matrix wired to IO expander

The rest of the posts for this project have been arranged by date.
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Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6
Completed projects from year 7
Completed projects from year 8

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