2 layers30 × 61.3 mm
2 layers113 × 72.6 mm
Twin Key
Sadrita404/Twin-KeyThis split keyboard basically fixes everything that sucks about standard typing. We took the logic of an ortholinear grid—where everything is perfectly predictable—and mashed it with a column stagger that actually matches how long your fingers are. Honestly, this form factor is a lifesaver for long hours of typing.
- Size
- 113 × 72.6 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 47
- Nets
- 41
- Pads
- 185
- Tracks, vias
- 282, 27
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 6 Jul 2026
- Updated
- 6 Jul 2026
Overview
Twin Key is an open-source printed circuit board by Sadrita404, from the Sadrita404/Twin-Key repository on GitHub, published under the MIT licence. It is a 2-layer board of 113 × 72.6 mm with 47 parts on 41 nets, routed with 282 tracks and 27 vias.
Its parts include 18 diodes, 18 switches, 1 IC and 1 connector. It belongs with the keyboards and input boards and the RP2040 boards of this library.
README
README.md|
|
| Title | Twin Key |
|---|---|
| Author | Sadrita Neogi |
Website for Twin Key go check it out - Live URL
what I have built
This split keyboard is basically fixes everything annoying about standard typing. We took the logic of an ortholinear grid (where everything is predictable) and mashed it together with a column stagger that actually matches how long your fingers are. For me this type of form factor keyboard is good for long hours of typing.
Why I choose this project?
So behind choosing this project is basically I love split keyboard and the way it just fold and compact. It is easy to carry and it is good for writing for long hours, so I wanted to make one for myself not to buy it but to make it for myself and customisable, so this is the reason I choose this project.
what I have learned
Through out making this project I have learned a lot of thing but the main that I gain strengh is listed below
- PCB design using KiCad
- Mechanical keyboard architecture
- KMK scripting
- Fusion 360 CAD Work
- How to choose Part's for project in budget
Features
- It's an 18 - 18 layout Split Keyboard .
- The connection between two keyboard are using 3.5mm TRRS to TRRS Cable.
- The main micro controller of this keyboard is RP2040-Zero and RP2040-Tiny.
- The PCB of this keyboard is reversible so that we can reduce the PCB wastage.
- This is an wired Keyboard
- This Keyboard is made for good ergonomic
- QMK Firmware support for this keyboard
- Hot-swappable ( for every keys )
- This is a low profile keyboard
- Custom 3d printed case and top plate
Components Used in this Build
| Item |
|---|
| PCB (MOQ 5) |
| RP2040-Zero (left side) |
| RP2040-Tiny (right side) |
| Kailh Choc v2 Low Profile Switches |
| Kailh Choc PG1350 Hot Swap Sockets |
| CFX MX Low Profile Keycaps |
| 1N4148 SOD-123 SMD Diode |
| PJ-320A TRRS Jack |
| M2×3 heat-set threaded inserts |
| M2×5 countersunk screws |
| 3.5mm TRRS to TRRS cable |
| Type-C to Type-C cable |
Firmware
Precompiled VIA-enabled firmware:
- Flash
twin_key_sadrita.uf2under Firmware/ to the RP2040 MCUs. - Load the via.json file in
Designtab for VIA configuration.
QMK source is available under firmware/QMK/keyboards/Twin-Key.
Journal - Journal.md
| Building Process | ||
|---|---|---|
Final PCB
|
▲ Left Side
|
▲ Right Side
|
Final Render
Bill of Materials
| Component Name | Purpose | Qty | Unit Price | Total Price | Source Link |
|---|---|---|---|---|---|
| PCB (moq5) | The Main Board | 5 | $1.54 | $7.70 | JLC PCB |
| RP2040-Zero (left side) | Micro Controller | 1 | $4.43 | $4.43 | Robu |
| RP2040-Tiny (right side) | Micro Controller | 1 | $6.26 | $6.26 | Robu |
| Kailh Choc v2 Low Profile Switches | The switches to press | 40 | $0.63 | $25.00 | Neomacro |
| Kailh Choc PG1350 Hot Swap Sockets | To put the switches | 40 | $0.18 | $7.00 | Neomacro |
| CFX MX Low Profile Keycaps | For the Switches | 1 | $26.30 | $26.30 | Neomacro |
| 1N4148 SOD-123 SMD Diode | For the PCB Board | 40 | $0.03 | $1.00 | Stackskb |
| PJ-320A TRRS Jack | For the Wire Connection | 2 | $0.50 | $1.00 | Stackskb |
| M2×3 heat-set threaded inserts | For fixing the case | 20 | $0.02 | $0.40 | Self Sourced |
| M2×5 countersunk screws | For fixing the case | 20 | $0.03 | $0.60 | Self Sourced |
| 3.5mm TRRS to TRRS Cable | For the keyboard connection | 1 | $4.80 | $4.80 | Amazon |
| Type C to Type C Cable | For the micro controller | 1 | $2.00 | $2.00 | Amazon |
| 3D Print | For the Case | 1 | $0.00 | $0.00 | #printing-legion |
| Shipping | Including PCB shipping | - | - | $13.40 | - |
| Total | $99.89 | ||||
| Round Off Budget | $100 |
I have provided the links for the parts I will be self-sourcing, so that if readers want to recreate this, they will be able to get all the parts.This is also updated on the bom.csv
Copyright and License
Copyright (c) 2026 Sadrita Neogi. All rights reserved.
All files are licensed under the MIT license. For more information, see the LICENSE.
Project Under Hack Club
Parts
47| Qty | Value | Footprint | References |
|---|---|---|---|
| 18 | Diode | ScottoKeebs_Components:Diode_SOD-123 | D1, D2, D3, D4, D5, D6, D7, D10, D11, D12, D13, D14, D15, D16, D17, D18 +2 |
| 18 | Keyswitch | PCM_marbastlib-xp-choc:SW_choc_Reversible_1u | S1, S2, S3, S4, S5, S6, S7, S10, S11, S12, S13, S14, S15, S16, S17, S18 +2 |
| 6 | MountingHole | MountingHole:MountingHole_2.2mm_M2 | H1, H2, H3, H4, H5, H6 |
| 3 | LOGO | LOGO | G***, G***, G*** |
| 1 | AudioJack4 | PCM_marbastlib-xp-various:CON_MJ-4PP-9_Reversible | J1 |
| 1 | RP2040_Zero | ScottoKeebs_MCU:RP2040_Zero | U1 |
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Questions
How big is the Twin Key PCB?
It measures 113 × 72.6 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Twin Key use?
47 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 Twin Key KiCad files?
From the Sadrita404/Twin-Key repository on GitHub, at the commit this page was made from: the board is PCB/Twin key.kicad_pcb and its schematic PCB/Twin key.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Twin Key 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).