2 layers256.8 × 95.3 mm Cardo, the printed circuit board in 3D

Cardo

Custom ergonomic wireless keyboard

Size: 256.8 × 95.3 mm
Copper layers: 2
Thickness: 1.58 mm
Parts: 55
Nets: 69
Pads: 320
Tracks, vias: 723, 187
Pours: 5
Routed: Yes
KiCad: KiCad 9.0 (file 20241229)
Created: 18 Jun 2025
Updated: 10 Sep 2026

Overview

Cardo is an open-source printed circuit board by jbro, from the jbro/cardo repository on GitHub. It is a 2-layer board of 256.8 × 95.3 mm with 55 parts on 69 nets, routed with 723 tracks and 187 vias.

It is built around the SSAJ110100. Its parts include 40 switches, 6 ICs and 1 connector. It belongs with the keyboards and input boards of this library.

Main components

SSAJ110100
SMD-10℃~+60℃ 10,000 cycles 10mA 3.8mm 5V Rectangular Columnar SMD(SMT) Tab SPDT Surface Mount, Right Angle SMD Slide Switches ROHSALPSALPINESlide Switches

README

README.md

Cardo Keyboard

This is a custom ergonomic wireless keyboard. The design language is based on the Reviung41 and the key layout is based on the Atreus keyboard without thumb keys.

Features

Columnar layout
Low profile
- Kailh Choc V1 switches
Sub 40% layout
- 36 1u keys
- 1.5u space bar
Wireless connectivity
Low part count
- No diodes
- Shift register based with a single column
- Mostly SMD components
Seeed XIAO nrf52840 micro controller
3D printable case (TBD)

Keymap

keymap

Schematics

schematics

PCB

PCB front PCB front populated PCB back

3d model

BOM

Part	Quantity	Description	Link
S2B-PH-SM4-TB(LF)(SN)	1	JST PH2 connector	Mouser
SSAJ110100	1	Slide switch	Mouser
7305-0-15-15-47-27-10-0	74	Mill Max 7305 "hot swap" socket	Mouser
EC05E1220401	2	Rotary encoder	Mouser
SN74HCS596DR	5	TI shift register with open-drain outputs	Mouser
102010448	1	Seeed XIAO nrf52840	Mouser or Seeed studio
LPR-CHC-SNS-010	37	Kailh Choc Sunset tactile V1 switches	Splitkb
KSM-MGG-1UN-010	34	1u MBK PBT Coloured Blank Keycaps	Splitkb
KSM-MGG-1UH-002	2	1u MBK PBT Coloured Blank Keycaps (Homing)	Splitkb
KSM-MGG-1U5-002	1	1.5u MBK PBT Coloured Blank Keycap	Splitkb
AM3144y	1	Li-Pol battery 60mAh, 3.7V, 501015	Ampul

License

This project is licensed under the Unlicense. Feel free to use, modify, and distribute this project as you wish.

Parts

Qty	Value	Footprint	References
36	SW_Push	PCM_Switch_Keyboard_Kailh:SW_Kailh_Choc_V1_1.00u	SW1, SW2, SW10, SW11, SW12, SW13, SW14, SW15, SW16, SW17, SW18, SW19, SW20, SW21, SW22, SW23 +20
5	SN74HCS596DR	Package_SO:SOIC-16_3.9x9.9mm_P1.27mm	U1, U2, U3, U5, U6
2	RotaryEncoder	My:Alps EC05E1220401	SW38, SW39
1	Conn_01x02_Pin	Connector_JST:JST_PH_S2B-PH-SM4-TB_1x02-1MP_P2.00mm_Horizontal	J1
1	MODULE_102010448	Snapeda:Seeed Studio XIAO nRF52840	U4
1	SSAJ110100	Samacsys:SSAJ110100_1	S1
1	SW_Push	PCM_Switch_Keyboard_Kailh:SW_Kailh_Choc_V1_1.50u	SW37

The 47 most common of 55 parts.

Questions

How big is the Cardo PCB?

It measures 256.8 × 95.3 mm and has 2 copper layers, 1.58 mm thick.

What parts does the Cardo use?

55 parts, built around the SSAJ110100. 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 Cardo KiCad files?

From the jbro/cardo repository on GitHub, at the commit this page was made from: the board is pcb/cardo.kicad_pcb and its schematic pcb/cardo.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Cardo design in my own project?

Its repository states no licence, so its author keeps all rights: ask jbro before reusing the design.

Category and platform

Keyboards and input

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/jbro-cardo" title="Cardo in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/jbro-cardo.jpg" alt="Cardo" width="1200" height="900">

A picture that opens the board, for a README

[![Cardo](https://pcbkit.io/embed/boards/jbro-cardo.jpg?size=s)](https://pcbkit.io/boards/jbro-cardo)

Source

Repository: jbro/cardo
Board file: pcb/cardo.kicad_pcb
Commit: 8ed989a
Licence: Not stated

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