2 layers36.8 × 34.7 mm
Tinylab proto1
espotek-org/Labrador
EspoTek Labrador is a USB device that transforms your PC or smartphone into a fully-featured electronics lab. This repo holds all of the source code!
79 parts1.2k
2 layers149.5 × 111.4 mm
Left side
WGRL/split-keyboardSplit keyboard with ble and usb. Custom pcb based on nrf52840 mcu module with specific firmware written in C (Zephyr)
- Size
- 149.5 × 111.4 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 79
- Nets
- 53
- Pads
- 228
- Tracks, vias
- 352, 5
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 13 Oct 2026
- Updated
- 13 Oct 2026
Overview
Left side is an open-source printed circuit board by WGRL, from the WGRL/split-keyboard repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 149.5 × 111.4 mm with 79 parts on 53 nets, routed with 352 tracks and 5 vias.
Its parts include 30 diodes, 30 switches, 6 capacitors, 6 ICs and 1 resistor. It belongs with the keyboards and input and radio and wireless boards and the nRF52 and nRF5x boards of this library.
README
README.mdsplit-keyboard
Split keyboard with ble and usb. Custom pcb based on nrf52840 mcu module with specific firmware written in C (Zephyr)
Firmware
All the firmware is stored in software directory. It also contains all the configs for Zephyr, Kconfig, CMAKE, scripts etc.
The source code is stored in software/src.
The right side connects to the left one using Bluetooth. It sends the hid codes of clicked keys with approximately 12 ms intervals. The left side takes together keys clicked on left and right side and sends it to the PC using eithter Bluetooth or USB. USB and Bluetooth are automatically switched. If the USB connection is detected it is a chosen communication method. If there is no USB connection then left side starts Bluetooth advertising or automatically connects to the PC if there is bonding already.
The name of the device is automatically WGRL_KEYBOARD, but you can change it in software/config/prj_left.conf in the # Names section.
Compilation
To program the mcu you use eithter
./scripts/run.sh left or ./scripts/run.sh right
depending on the side
Electronics
The files for printed PCBs are stored in hardware directory.
This is for personal use so note that the boards don't have any ESD, reverse polarity, overvoltage protection etc. Also it lacks extra capacitor to sustain battery voltage.
PCB
Printed PCBs. The files are in hardware directory. They are based on only THT elements for easier soldering.
Parts
79| Qty | Value | Footprint | References |
|---|---|---|---|
| 30 | 1N4148 | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D1, D2, D15, D16, D17, D18, D19, D20, D21, D22, D23, D24, D25, D26, D27, D28 +14 |
| 30 | SW_Push | Button_Switch_Keyboard:SW_Cherry_MX_1.00u_Plate | SW1, SW2, SW10, SW11, SW12, SW13, SW14, SW15, SW16, SW17, SW18, SW19, SW20, SW21, SW22, SW23 +14 |
| 5 | 100n | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P2.50mm | C1, C3, C4, C5, C6 |
| 5 | ~ | nrf52840:PL9823-F8 | U2, U3, U4, U5, U6 |
| 4 | MountingHole | MountingHole:MountingHole_2.7mm_M2.5_DIN965_Pad | H1, H2, H3, H4 |
| 1 | 100 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R7 |
| 1 | 470u | Capacitor_THT:CP_Radial_D8.0mm_P3.50mm | C2 |
| 1 | Li-Pol Battery | Connector_PinSocket_2.54mm:PinSocket_2x01_P2.54mm_Vertical | B1 |
| 1 | SS22T25 | nrf52840:slider | SW_POW1 |
| 1 | XIAO-nRF52840-DIP_SMD | nrf52840:XIAO-nRF52840-DIP_SMD | U1 |
Questions
How big is the Left side PCB?
It measures 149.5 × 111.4 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Left side use?
79 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 Left side KiCad files?
From the WGRL/split-keyboard repository on GitHub, at the commit this page was made from: the board is hardware/left_side/left_side.kicad_pcb and its schematic hardware/left_side/left_side.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Left side design in my own project?
Its repository publishes it under the GPL-3.0 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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