2 layers173.4 × 161.4 mm
ExtraDox Left
blastrock/ExtraDox
An ergonomic custom keyboard design inspired by the ErgoDox
121 parts45
2 layers173.4 × 161.4 mm
ExtraDox Right
blastrock/ExtraDox45An ergonomic custom keyboard design inspired by the ErgoDox
- Size
- 173.4 × 161.4 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 140
- Nets
- 106
- Pads
- 611
- Tracks, vias
- 861, 129
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 6 Dec 2022
- Updated
- 22 Apr 2026
Overview
ExtraDox Right is an open-source printed circuit board by blastrock, from the blastrock/ExtraDox repository on GitHub. It is a 2-layer board of 173.4 × 161.4 mm with 140 parts on 106 nets, routed with 861 tracks and 129 vias.
It is built around the ATMEGA32U4-MU. Its parts include 48 diodes, 45 switches, 27 resistors, 8 capacitors and 2 connectors. It belongs with the keyboards and input boards and the AVR (ATmega, ATtiny) boards of this library.
Main components
1README
README.mdExtraDox (v2)
The ExtraDox is a split keyboard based off the ErgoDox. The main difference is that it has an additional row of keys on the top. Also, it is a low-profile keyboard designed for Choc v1 switches.
It features:
- An additional row of keys over the ErgoDox
- An USB-C port
- A single-board design (actually two boards), no extra controller board
- A TRRS connection between the two sides
- The 3 usual status LED
- The case is only 8mm thick, the keys are 18mm high from the desk
What you need to build this keyboard
- The PCBs and their components (the MCU is soldered on the main board)
- The 3D-printed case
- 14x M2.5x8 screws and nuts
- 10x rubber pads to put under the keyboard to prevent slipping
- 90x Kailh Choc Hotswap sockets
- 90x Kailh Choc switches
- 82x 1u key caps
- 4x 1.5u key caps
- 4x 2u key caps
- 3x SMD status LED (see the Kicad project for details)
- 2x TRRS connector (see the Kicad project for details)
- 1x TRRS cable
- 1x USB-c cable
About this keyboard
PCB
The PCB is designed in Kicad. It is a SMD design and the project includes component references from JLCPCB.
Case
The case is designed to be 3D-printed. The case is screwed together with 7 M2.5x8 screws on each side, and their corresponding bolts.
Firmware
Here is a a fork of the QMK firmware with support for the ExtraDox.
Known issues
Some capacitors are located right under an hotswap socket. It is still possible to solder it, but the socket gets a little tilted.
License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Parts
140| Qty | Value | Footprint | References |
|---|---|---|---|
| 45 | D | Diode_SMD:D_SOD-123F | D10, D11, D12, D13, D14, D15, D16, D20, D21, D22, D23, D24, D25, D26, D27, D28 +29 |
| 41 | SW_Push | additional-footprints:KailhHotswapChoc1 | SW0:7, SW0:8, SW0:9, SW0:12, SW1:9, SW1:10, SW1:11, SW1:12, SW1:13, SW2:8, SW2:9, SW2:10, SW2:11, SW2:12, SW2:13, SW3:10 +25 |
| 15 | 470 | Resistor_SMD:R_0402_1005Metric | R11, R12, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27 |
| 3 | 0.1uF | Capacitor_SMD:C_0402_1005Metric | C4, C7, C8 |
| 3 | 100 | Resistor_SMD:R_0402_1005Metric | R7, R8, R14 |
| 2 | 12pF | Capacitor_SMD:C_0402_1005Metric | C1, C2 |
| 2 | 1uF | Capacitor_SMD:C_0402_1005Metric | C3, C6 |
| 2 | 2.2k | Resistor_SMD:R_0402_1005Metric | R9, R10 |
| 2 | 22 | Resistor_SMD:R_0402_1005Metric | R2, R3 |
| 2 | 5.1k | Resistor_SMD:R_0402_1005Metric | R4, R5 |
| 2 | SW_Push | additional-footprints:KailhHotswapChoc2 | SW0:10, SW0:11 |
| 2 | SW_Push | additional-footprints:KailhHotswapChoc15 | SW2:7, SW4:7 |
| 1 | 10k | Resistor_SMD:R_0402_1005Metric | R6 |
| 1 | 10uF | Capacitor_SMD:C_0402_1005Metric | C5 |
| 1 | 16MHz | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
| 1 | 180 | Resistor_SMD:R_0402_1005Metric | R13 |
| 1 | 1K | Resistor_SMD:R_0402_1005Metric | R1 |
| 1 | ATmega32U4-M | additional-footprints:QFN-44-1EP_7x7mm_P0.5mm_EP5.2x5.2mm_ThermalVias_JLCPCB | U1 |
| 1 | Blue | Diode_SMD:D_0603_1608Metric | D19 |
| 1 | Green | Diode_SMD:D_0603_1608Metric | D18 |
| 1 | Red | Diode_SMD:D_0603_1608Metric | D17 |
| 1 | SW_Push | additional-footprints:TS-1087S | SWB1 |
| 1 | TRRS | additional-footprints:TRRS-PJ-320A | J2 |
| 1 | USB_C_Receptacle_USB2.0 | additional-footprints:HRS_CX90M-16P | J1 |
The 133 most common of 140 parts.
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Questions
How big is the ExtraDox Right PCB?
It measures 173.4 × 161.4 mm and has 2 copper layers, 1.6 mm thick.
What parts does the ExtraDox Right use?
140 parts, built around the ATMEGA32U4-MU. 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 ExtraDox Right KiCad files?
From the blastrock/ExtraDox repository on GitHub, at the commit this page was made from: the board is PCB/Right/ExtraDox-Right.kicad_pcb and its schematic PCB/Left/ExtraDox-Left.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the ExtraDox Right design in my own project?
Its repository states no licence, so its author keeps all rights: ask blastrock before reusing the design.