

a small compact 3x5+3 split ortho keyboard
- Size
- 243.2 × 106 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 113
- Nets
- 121
- Pads
- 586
- Tracks, vias
- 1,164, 151
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 7 Mar 2021
- Updated
- 12 Dec 2022
Overview
3W6 is an open-source printed circuit board by weteor, from the weteor/3W6 repository on GitHub. It is a 2-layer board of 243.2 × 106 mm with 113 parts on 121 nets, routed with 1,164 tracks and 151 vias.
It is built around the ATMEGA32U4-AU and PCA9555PW. Its parts include 41 diodes, 37 switches, 9 capacitors, 9 resistors and 3 connectors. It belongs with the keyboards and input boards and the AVR (ATmega, ATtiny) boards of this library.
Main components
2ATMEGA32U4-AU
QFP-44(10x10)-40℃~+85℃ 10bit 16MHz 1KB 2.5KB 2.7V~5.5V 26 32KB 8 Bit AVR Built-in FLASH QFP-44(10x10) Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)PCA9555PW
TSSOP-24-40℃~+85℃ 1.1uA 16 2.3V~5.5V 3mA 400kHz 8 I2C、SMBus Interrupt Output Reset function、Cascade and address expansion TSSOP-24 I/O Expanders ROHSNXP SemiconductorsI/O Expanders
README
README.md
3w6 - split ortholinear keyboard
The 3w6 is a low profile, split ortholinear keyboard with 36 keys.
I needed a keyboard for work and wasn't really satisfied with the available alternatives (namely Corne, Kyria and Ferris), mostly because they were rather large and didn't had the spacing I would like.
It's designed to be a no frills, cheap and small keyboard to be taken everywhere.
So no hotswap, no multiple switchtypes, no encoders, no LEDs.
BUT with onboard controllers (so no extra ProMicros, Elite-C), production files including SMT assembly files, and sturdy through hole mounted USB-C connectors.
revision 2.2
changes:
- combi footprint to be able to use the AU or MU variant of the AtMega32U4.
- add BOM files for each AU and MU variant, so you can choose the cheaper one.
revision 2
changes:
- new middle plate (1.6mm, better 2.0mm) instead of diodes. Uses Aluminium PCBs as a cheaper alternative to lasered aluminium.
- pimoroni trackball support (can only be used combined with the new middle plate when used with the plate)
- plate is now 1.2mm thick, to fit the chocs better. Needs middle plate, since the cutouts of the USB-Connectors were left out. There is enough space for them under the plate, when the middle plate is in place.
- added mounting holes to support tenting puck from splitkb.com. Due to insufficient space not all 4 holes are supported, but 3 screws should be enough to hold everything comfortably in position. Can only be used plateless!
- package for the MCU was changed from QFN44 to TQFP44, since the previous one wasn't available. Can now be soldered/replaced by hand if need.
- IO-expander was changed from TCA9555RTWR to TCA9555PWR (alternativly PCA9555PW), since the previous one wasn't available. Package changed from WQFN24 to TSSOP24. Can now be soldered/replaced by hand if need.
- Board can now be soldered by hand if needed (challenging though, 0402 components).
try it
You may also compare the layout with other layouts of other layouts at https://jhelvy.shinyapps.io/splitkbcompare/ .
Or you can print this file to test if you like the layout. Or mount it to some cardboard and test it with your favourite switches.
production files
If you want to build one yourself, grab the Gerber files here and give it a go.
And if 3d printing is your thing, files for plate and midlayer can be found here (made by the great bomtarnes, thanks a lot!)
build instructions
you may find instructions here:
- rev1 (deprecated): build instructions rev1
- rev2 (current) : build instructions rev2
firmware
This keyboard uses QMK firmware. You can find everything you need to build a firmware for this board in the QMK Repository.
Here are some instructions on how to set up your QMK environment and a few notes specifically for the 3w6.
the rest
Everything in this repository is free to use however you might see fit. If you want to support me and my projects, please consider linking back to this repository if you build/change/use anything.
If you would like to send me a tip, you could do it here (Please don't feel like you have to).
rev2(current)

rev1

Parts
113| Qty | Value | Footprint | References |
|---|---|---|---|
| 41 | D | Weteor:D_SOD-123 | D2, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23, D24 +25 |
| 33 | SW_Push | Weteor:Kailh_Choc_1u | SW2, SW10, SW11, SW12, SW13, SW14, SW15, SW16, SW18, SW19, SW20, SW21, SW22, SW23, SW24, SW25 +17 |
| 5 | 0.1uF | Weteor:C_0402_HandSolder | C3, C4, C5, C6, C7 |
| 3 | 10k | Weteor:R_0402_HandSolder | R5, R8, R9 |
| 2 | 22R | Weteor:R_0402_HandSolder | R6, R7 |
| 2 | 22pF | Weteor:C_0402_HandSolder | C1, C2 |
| 2 | 4.7k | Weteor:R_0402_HandSolder | R3, R4 |
| 2 | 5.1k | Weteor:R_0402_HandSolder | R1, R2 |
| 2 | SW_Push | Weteor:Kailh_Choc_1.5u | SW33, SW37 |
| 1 | 16MHZ | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
| 1 | 1uF | Weteor:C_0402_HandSolder | C9 |
| 1 | 4.7uF | Weteor:C_0402_HandSolder | C8 |
| 1 | 500mA | Fuse:Fuse_1206_3216Metric | F1 |
| 1 | ATmega32U4-AU | Weteor:AtMega32U4-Combie | U1 |
| 1 | PCA9555PW | Package_SO:TSSOP-24_4.4x7.8mm_P0.65mm | U2 |
| 1 | SW_Push | Weteor:Micro_Push_Button_3x6x2.5mm | SW1 |
| 1 | Trackball_Choc_Combi | Weteor:trackball_choc_combi | SW17 |
| 1 | USB_C I2C_L | Weteor:USB-C-12-Pin-MidMount | J2 |
| 1 | USB_C I2C_R | Weteor:USB-C-12-Pin-MidMount | J3 |
| 1 | USB_C Main | Weteor:USB-C-12-Pin-MidMount | J1 |
The 103 most common of 113 parts.
Questions
How big is the 3W6 PCB?
It measures 243.2 × 106 mm and has 2 copper layers, 1.6 mm thick.
What parts does the 3W6 use?
113 parts, built around the ATMEGA32U4-AU and PCA9555PW. 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 3W6 KiCad files?
From the weteor/3W6 repository on GitHub, at the commit this page was made from: the board is pcb/3w6/3W6.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the 3W6 design in my own project?
Its repository states no licence, so its author keeps all rights: ask weteor before reusing the design.
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