Schematic Logic & Physical PCB Layout Complete!

Today was a massive build day for KG’s HACKPAD. I completely finished the electrical schematic and made the jump into the physical PCB design phase in KiCad.

Here is what I engineered today:

Mapped the brain: Wired the Seeed Studio XIAO RP2040 to handle a 3x3 mechanical switch matrix, utilizing a COL2ROW diode orientation to prevent ghosting.

Routed the peripherals: Hooked up the EC11 Rotary Encoder (pins D9/D10), an I2C SSD1306 OLED screen (D4/D5), and the data line for the SK6812 RGB underglow (D8).

Cleared the ERC: Resolved all unconnected pins, established the no-connect flags, and locked in the power flags for a flawless 0-error schematic check.

Built the physical layout: Pushed the 3D footprints to the PCB editor, established a custom 19.05mm grid (the golden rule for mechanical switches to prevent keycap collision), and snapped my 8 switches and the encoder into a mathematically perfect 3x3 square.

The logic is locked in, and the physical footprints are perfectly placed. Next up is routing the actual copper traces to connect everything!