2 layers254.1 × 87.2 mm
2 layers303 × 104.5 mm
42 keys ergonomic keyboard
- Size
- 303 × 104.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 85
- Nets
- 71
- Pads
- 688
- Tracks, vias
- 854, 24
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 11 Mar 2018
- Updated
- 15 Jul 2026
Overview
42 is an open-source printed circuit board by nglgzz, from the nglgzz/42 repository on GitHub, published under the MIT licence. It is a 2-layer board of 303 × 104.5 mm with 85 parts on 71 nets, routed with 854 tracks and 24 vias.
Its parts include 42 diodes, 42 switches and 1 IC. It belongs with the keyboards and input boards and the AVR (ATmega, ATtiny) boards of this library.
README
README.md42 Keyboard
A mechanical keyboard with 42 keys.
Features
- 40% – Each key is at most one unit of distance from where the finger that should press it rests. In other words there's no awkward reaching for keys that are placed far from the home row.
- Staggered columns - Because a comfortable keyboard should follow the shape of your hands.
- Low profile - The PCB supports Choc (PG1350) switch mounts as well as Cherry MX/Alps.
Pics
- Finished keyboard
- PCB
Project Structure
-
Build – Build log, bill of materials, tips on where to source parts, assembling tips, learning resources I used while designing this keyboard.
-
Case – Fusion 360 project and STL files for 3D printing the enclosure.
-
Firmware – QMK configuration. There is a Makefile to build and load the firmware.
-
PCB – Kicad project and Gerber files for manufacturing the circuit board.
Why?
In January 2018 I wanted a keyboard with a specific set of features. The simplest options to get that keyboard were to wait for a group-buy or build my own. Waiting time and costs for both options seemed similar, so I went with the option where I would learn the most.
Needs and knowledge changed over time, so I made different iterations to add new features and account for the lessons learned from previous builds.
Feedback
If you have some feedback or questions, feel free to create an issue. Your input is more than welcome!
Previous Versions
- version 3.1 –
custom PCB, QMK firmware, USB C, Elite-C v4
- version 3 –
custom PCB, QMK firmware, Bluetooth, micro USB, Adafruit Feather 32u4 Bluefruit LE
- version 2 –
handwired, QMK firmware, Bluetooth, micro USB, Adafruit Feather 32u4 Bluefruit LE
- version 1:
custom PCB, Split, TMK firmware, USB C, Teensy 2.0
Parts
85| Qty | Value | Footprint | References |
|---|---|---|---|
| 42 | D | Keyboard_Parts:D_SOD123_axial | D0, D0A1, D0B1, D1, D1A1, D1B1, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19 +26 |
| 42 | KEYSW | Keebio-Parts:MX-Alps-Choc-1U-NoLED | K0, K0A1, K0B1, K1, K1A1, K1B1, K10, K11, K12, K13, K14, K15, K16, K17, K18, K19 +26 |
| 1 | Elite-C | Keebio-Parts:Elite-C-castellated-29pin-holes | U1 |
Questions
How big is the 42 PCB?
It measures 303 × 104.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the 42 use?
85 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the 42 KiCad files?
From the nglgzz/42 repository on GitHub, at the commit this page was made from: the board is pcb/kicad/pcb.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the 42 design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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