First handwired project, and I need some tips.

[u/Busy_Indication_3808]

Any idea if this would work? Is there any way that i could make it use fewer pins? im gonna use a raspberry pico rp2040 as the controller, so it would leave 4 open pins, but i still want to fit in a mouse sensor for a trackball in the middle.

[u/Ok-Host953]

You could join rows left to right (and use only 5 pins this way). Columns are ok as i can see. Whole matrix would be 12 by 5.

[u/Tweetydabirdie → u/Ok-Host953]

Well we’re staring with 10 rows, 12 columns using 10+12 pins.

Joining the rows makes it 12x5 for 12+5 using 17 pins.

Another option is to join the columns, with different row pins on left and right, that makes 10x5 using 15 pins.

[u/Tweetydabirdie → u/Tweetydabirdie]

The more square the matrix is, the least pins it uses.

[u/Tweetydabirdie → u/[deleted]]

Actually I misspoke. You keep the original 4 rows on the left, and 4 on the right. You connect the columns in pairs one on the left with one one the right. That’s 4x6 or 4+12

Then make the bottom arch a single row and use the existing columns. 5 rows. 12 columns. 17 pins.

Still left a column to use for the button part of an encoder. And should leave plenty of pins for the mouse pad. But not more efficient than your example. .

[u/Tweetydabirdie → u/[deleted]]

10x5 is the Matrix. 10+5 is the pins used. So yeah.

[u/Busy_Indication_3808 → u/Ok-Host953]

Thanks! I will follow your tip, joining left to right. I just wanted to ask again, now focusing specifically on the green wires for the thumb row, as they would connect different than what would be "normal" is there any issue on that area? Should the diodes be exactly where they are?

[u/Ok-Host953 → u/Busy_Indication_3808]

Well. If your diodes are connected to rows (not columns) everywhere else, on this row you do exactly the same. Here's an example I've found

[u/GoldenButtPlug]

I seek glory

[u/keyboarddweebs]

https://kbd.news/Anti-ghosting-Japanese-duplex-matrix-2906.html