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:material-keyboard-variant: Open-Source Hardware & Firmware

mlego — Modular LEGO Ortholinear Keyboards

Custom ISO-friendly ortholinear mechanical keyboards, macropads, POS terminal conversions, and QMK/ZMK firmware experiments — all mounted in modular LEGO cases.

Explore Keyboards Assembly Guide GitLab Repository

mlego keyboard collection

  • What This Project Is

    • Fun & experimental — designed for learning electronics, PCB routing, and firmware
    • Educational — documented schematics, shift-register matrices, and QMK/ZMK configs
    • Functional daily drivers — full ISO keycap compatibility on compact ortho grids
    • Budget-friendly — cheap PCBs and LEGO plate enclosures (until switches & MT3 keycaps!)

  • What This Project Is Not

    • Not "endgame" — this is an evolving maker playground rather than a commercial CNC custom kit
    • Every revision explores a new microcontroller, display technology (OLED, e-ink, Sharp Memory, IPS LCD), or matrix scanning circuit

Explore the Collection

Motivation & Background

This project started as a fun exploration into building an ISO-friendly ortholinear keyboard. Initially conceived as a 6×13 grid, it settled into a 5×13 (and 5×14 with a dedicated rotary encoder column) layout as the sweet spot between compactness and standard ISO keycap compatibility. Read the original story on Alin's blog.

If you are exploring similar ortholinear ecosystems, check out the 6×13 Index-Tab, 4×13 Nack, mechkey.org, and mechdb.net.

What Makes mlego Keyboards Special?

  • Modular LEGO Case: PCBs are drilled to official LEGO stud pitch and thickness (1.6 mm), snapping directly onto LEGO plates and bricks for customizable height, tilt angle, and colors.
  • Accessible Reference MCUs: Built around off-the-shelf development boards — STM32F103 / GD32F303 BluePill, WeAct STM32F401/F411 BlackPill, STM32G431, Raspberry Pi Pico (RP2040), Pro Micro RP2040 (Splinky/Helios), nice!nano, and Seeed Studio XIAO RP2040 / XIAO nRF52840 BLE.
  • Shift-Register Matrix Scanning: Later revisions pack full 65–66 key matrices + displays + encoders onto tiny 11-pin XIAO controllers using chained 74HC595, 74HC165, and buffered 74HC589 SPI shift registers.
  • Rich Peripherals: Clickable EC11 rotary encoders, per-key and underglow RGB LEDs, 128×32 I²C OLEDs, WeAct SSD1680 e-ink displays, Sharp Memory displays, and ST7735 IPS LCDs.

Keyboard Lineup at a Glance

Model Layout Keys MCU Platform Peripherals Firmware
m66 5×14 Ortho 66 Pro Micro RP2040 / nice!nano / XIAO Clickable Encoder, Per-Key RGB, OLED / E-Ink / Sharp / LCD QMK & ZMK
m65 5×13 Ortho 65–66 XIAO RP2040 / BLE, Pico, BlackPill Rotary Encoder, OLED / E-Ink, RGB Strip QMK & ZMK
m60 5×12 Ortho 60 BlackPill STM32F401 / RP2040 Pico Rotary Encoder, OLED (Rev 2), RGB Strip QMK
m60 Split 5×12 Split 60 2× BlackPill STM32F401 / F411 Dual Encoders, RGB Strip, TRS/JST Split QMK
m48 4×12 Ortho 48 BlackPill STM32F401 / F411 Rotary Encoder, RGB Strip QMK
m20 5×4 Pad 20 RP2040 Pico / WeAct RP2040 Rotary Encoder, OLED, MX & Choc v2 QMK
m8 2×4 Pad 8 XIAO RP2040 + Shift Registers Clickable Encoder, SPI E-Ink & I²C OLED QMK
m4 2×2 Pad 4 XIAO nRF52840 BLE / XIAO RP2040 Rotary Encoder, OLED, 2× 74HC595 ZMK & QMK

Builder Tips & LEGO Tolerances

LEGO Dimensional Tolerances

PCB mounting holes are drilled to official LEGO stud dimensions. However, both PCB CNC drills and LEGO injection molds have manufacturing tolerances — and LEGO clutch power varies slightly by plastic color.

  • Use 1×2 and 1×4 plates along the perimeter for the best fit. Longer plates can exert surprising force and slightly bow the PCB.
  • For the 16×32 double-sided baseplate (or two 16×16 plates), gray compatible baseplates tend to sit flattest without flexing the PCB.

Typing Angle vs. Low-Profile Flat Base

If you prefer a zero-degree flat typing profile, use a single-sided baseplate with one intermediate plate layer (total thickness ≈ 8 mm). For a ~6° typing angle, stack a full LEGO brick + plate along the rear edge.

Acoustic Foam Dampening

Lining the bottom cavity of the LEGO case with inexpensive A4 hobbycraft EVA/neoprene foam sheets makes a dramatic improvement to typing acoustics and eliminates hollow plastic resonance.