m48 — 4×12 Planck-Style LEGO Keyboard

A compact, Planck-style 4×12 ortholinear mechanical keyboard mounted in a modular LEGO enclosure with an optional rotary encoder and addressable LED strip.

Status: Tested All OK!

* [x] Gerbers designed
* [x] Firmware
* [x] Breadboard tested
* [x] Gerbers printed
* [x] Board tested

Features

• Layout: 4×12 ortholinear (48 keys, 5-pin PCB-mount MX switches)
• Controller: WeAct STM32F401 or STM32F411 BlackPill
• Peripherals: 1× EC11 rotary encoder, status LED, optional 3-pin RGB LED strip
• Firmware: QMK

3D Render & PCBs

3D Render

Printed PCB (Front & Back)

KiCad Layout

BOM

• 1× WeAct STM32F401 BlackPill with headers
• 1× 40-pin DIL/DIP socket
• 48× 1N4148 signal diodes (DO-35 through-hole)
• 48× 5-pin Cherry MX–compatible switches
• 1× EC11 rotary encoder
• 2× 220 Ω or 350 Ω resistors (for status LEDs and boot pull-up; see m65 BOM notes)
• 1× status indicator LED
• Optional: 3-pin addressable LED strip
• LEGO 16×32 baseplate and perimeter plates/bricks

Case & Assembly

• LEGO Enclosure: See the m65 Case & Thickness section.
• Soldering & Build: Follow the step-by-step Assembly Guide.

Gerbers & KiCad

Production-ready Gerbers for JLCPCB:

• Rev 1 Gerbers (STM32F401)

Full KiCad project files are available in m-lego/m48 on GitLab. Prebuilt UF2 firmware is available at mlego_m48_rev1_default.uf2.

Firmware

git clone --recurse-submodules -b mlego https://github.com/alinelena/qmk_firmware.git qmk-alin
cd qmk-alin

qmk compile -kb m-lego/m48/rev1 -km default

# or using make:
make m-lego/m48/rev1:default

Pinout Reference

• Columns (C0–C11): A10, A15, B3, B4, B5, B7, B6, A1, A2, A3, A4, A5
• Rows (R0–R3): A6, A7, B0, B10
• Encoder: Pad_A = A0, Pad_B = A8

Indicator / RGB	Pin
NUM_LOCK	B12
CAPS_LOCK	C13
SCROLL_LOCK	B13
RGB_DI	B15