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2 layers134 × 106.7 mmChitin, the printed circuit board in 3D

A custom split ergomech keyboard

Size
134 × 106.7 mm
Copper layers
2
Thickness
1.6 mm
Parts
102
Nets
78
Pads
636
Tracks, vias
1,538, 128
Pours
1
Routed
Yes
KiCad
KiCad 9.0 (file 20241229)
Created
14 Dec 2025
Updated
19 Feb 2026

Overview

Chitin is an open-source printed circuit board by Scybin, from the Scybin/chitin repository on GitHub, published under the MIT licence. It is a 2-layer board of 134 × 106.7 mm with 102 parts on 78 nets, routed with 1,538 tracks and 128 vias.

Its parts include 58 diodes, 29 switches and 1 connector. It belongs with the keyboards and input boards of this library.

README

README.md

chitin

chitin

📚 Table of Contents

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⚠️ Disclaimer

This project has reached the fully working prototype stage. All core features have been tested and function as intended. However, as with any DIY hardware project, you should carefully review all files before manufacturing or assembly. The author(s) cannot guarantee flawless operation in every environment or configuration.

The author(s) take no responsibility for any damage, issues, or legal trouble that might result from using this project (see the license). Be sure to follow local laws regarding radio frequencies and DIY electronics.

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⌨️ Welcome

Chitin is a custom mechanical keyboard designed for ergonomic comfort, wireless functionality, and useful features. All hardware and software aspects of this project are open source and documented in this repository. Best of all, the build is completely hot-swappable, meaning assembly and disassembly can be done with ease. This includes the microcontroller, switches, lipo battery, and even the trackball. The chitin keyboard is based off my original keyboard design: scyboard.

The trackball used in this build is a Pimoroni PIM447 breakout with a Qw/ST connector. The connector is useful because you can use the trackball without needing to solder the mounting holes to the microcontroller. Included on the chitin PCB is a footprint for a JST SH connector, which you can use to connect the trackball to the board.

chitin_top_open

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⚙️ Features

  • Ergonomic split layout
  • ZMK firmware support
  • USB-C connectivity & battery charging
  • Bluetooth compatible
  • Customizable keymaps, layers, and macros
  • Trackball which can be programmed as a pointing device
  • Layout and case design is declared using Ergogen
  • KiCad traces auto-routed using Freerouting
  • Open source
  • Hot-swap and semi-modular

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💾 Firmware

To get started, I recommend forking my personal repository for chitin here: zmk-config-chitin.

  • To flash the keyboard, follow the flashing instructions in the ZMK docs.
  • Making modifications to the keyboard can be done within the config folder.
  • My build sets the central device to the right half of the keyboard, and the peripheral to the left half. Making changes to which half the trackball resides on, or excluding the trackball from the build requires many changes to the code in the chitin repository and source module.
  • The chitin ZMK repository also uses my Pimoroni trackball driver module (derived from mwandzik's driver) here: zmk-driver-pim447.

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📦 Parts List

I am not sponsored or affiliated with the vendors linked below. This is where I prefer to purchase my products.

PartQuantityDescriptionPurchase LinkDatasheet
Microcontroller2nice!nano v2.0Nice Keyboarrds nice!nano v2.0Nordic nRF52840
Pin Headers4Controller socketing system (4mm)MAC8 spring-loaded pin headersMAC8 spring-loaded pin headers specifications
Reset Button2Panasonic miniature momentary buttonPanasonic Reset ButtonEVQPUC02K
Power Switch2Alps miniature SPDT switchALPS Powr SwitchSSSS811101
Battery Connector2JST PH 2.0mmJST Battery JackJST_PH_S2B-PH-K_1x02_P2.00mm_Horizontal
Battery23.7V LiPo 1200mAh (w/ JST adapter)Lithium Ion Polymer Battery - 3.7v 1200mAh301230
Diode57SMD DiodeSemtech SMD DiodesSOD-123
Hotswap Socket57Kailh MX PCB SocketKailh Hotswap SocketsCPG151101S11
MX Switch57JWICK Linear SwitchesJWK JWICK Linear SwitchesMX Series Keyswitch
MX Keycap5755 x 1u, 2 x 1.5uDSA KeycapsDSA Keycap Project
M2x15 Standoff18Standoffs for plateNewark M2x15 StandoffFarnell Datasheet
M2x5 Screw8Screws to connect bottom case to top caseCO-RODE Screw Kit
M2x6 Screw18Screws for bottom case and top plateCO-RODE Screw Kit
M2.5x8 Screw4Screws to hold trackball in top caseCO-RODE Screw Kit
M2x3 Insert Nut8Inserts for top casesuxcell Knurled Insert Nuts
M2.5x2 Nut4Nuts to hold trackball in top caseNewark M2.5 Hex NutsFarnell Datasheet
Trackball Breakout1Pimoroni RGBW Trackball BreakoutTrackball Breakout by PimoroniTrackball Dimensions
Qwiic Connector1JST SH 4-pin Right Angle ConnectorJST SH 4-pin Right Angle Connector (10-pack) - Qwiic CompatibleKAWEEI TECHNOLOGY 1.0MM WAFER 90 SMT TYPE REEL PACKAGE
Bottom Case23D printed bottom caseCase Files Found Here
Top Case23D printed top case (tb case for trackball)Case Files Found Here

NOTE: The trackball replaces the position of 1 switch from the keyboard layout. If not incorporating a trackball in the build, add 1 quantity to each of the following parts:

  • Diode
  • Hotswap Socket
  • MX Switch
  • 1u MX Keycap

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🛠️ Build Images

chitin_pcb

chitin_plates

chitin_bottom_open

chitin_bottom_assembled

chitin_side

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📄 License

This project is licensed under the MIT License. See the LICENSE file for details.

Parts

102
QtyValueFootprintReferences
58ceoloide:diode_tht_sod123D1, D2, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23 +42
29ceoloide:switch_mxS1, S2, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23 +13
9ceoloide:mounting_hole_npthMH1, MH2, MH3, MH4, MH5, MH6, MH7, MH8, MH9
1scybin:mcu_nice_nanoMCU1
1ceoloide:battery_connector_jst_ph_2JST1
1ceoloide:reset_switch_smd_sideRST1
1logo_dual_chitinLOGO1
1ceoloide:power_switch_smd_sidePWR1
1qwiik_jstscybin:qwiik_jstJ1

Questions

How big is the Chitin PCB?

It measures 134 × 106.7 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Chitin use?

102 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 Chitin KiCad files?

From the Scybin/chitin repository on GitHub, at the commit this page was made from: the board is kicad/chitin.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.

Can I use the Chitin 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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