2 layers44.5 × 46.9 mm
OSO SWAT B1-jig
joeycastillo/Sensor-Watch
A board replacement for the classic Casio F-91W wristwatch
31 parts2.1k
2 layers94.5 × 94 mm
Slackpad
faded-debug/SlackpadA programmable pad that includes 12 keys used for keyboard shortcuts in apps like Slack and OBS.
- Size
- 94.5 × 94 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 31
- Nets
- 26
- Pads
- 109
- Tracks, vias
- 179, 0
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 8 Aug 2026
- Updated
- 13 Aug 2026
Overview
Slackpad is an open-source printed circuit board by faded-debug, from the faded-debug/Slackpad repository on GitHub. It is a 2-layer board of 94.5 × 94 mm with 31 parts on 26 nets, routed with 179 tracks and 0 vias.
Its parts include 13 switches, 12 diodes and 1 IC. It belongs with the keyboards and input boards of this library.
README
README.mdSlackpad
A programmable pad that includes 12 keys used for keyboard shortcuts in apps like Slack and OBS.
Specifications
| Microcontroller | Seeed XIAO RP2040 |
| Keys | 12 (4x3 switch matrix) |
| Rotary encoder | 1x EC11 with push button |
| Switches | Cherry MX compatible, 1u keycaps |
| Diodes | 12x 1N4148 (DO-35, through-hole) |
| PCB | 94.5 x 94.0 mm, 2 layers |
| Mounting | 4x M3 screws |
| Case | 3D printed, tray with a top plate, 99.5 x 99.0 x 14.5 mm |
| Firmware | KMK (CircuitPython) |
Pinout
| Signal | XIAO pin |
|---|---|
| COL1 | D3 |
| COL2 | D4 |
| COL3 | D5 |
| COL4 | D6 |
| ROW1 | D7 |
| ROW2 | D8 |
| ROW3 | D9 |
| Encoder A | D0 |
| Encoder B | D1 |
| Encoder switch | D2 |
Diode direction is COL2ROW — current flows from the column, through the
switch and its diode, into the row.
Note: on the PCB the physical columns run right to left, so COL1 is the
rightmost column.
Case
The case is a tray with a lid. The PCB drops into the tray and is surrounded by walls on all four sides; the top plate closes it from above and carries the switches.
| Outer dimensions | 99.5 x 99.0 x 14.5 mm |
| Wall thickness | 2 mm |
| Clearance around the PCB | 0.5 mm per side |
| Space under the PCB | 3 mm, for the through-hole leads |
| Space between PCB and top plate | 3.5 mm, the Cherry MX plate mount standard |
| Top plate | 1.5 mm, 14 x 14 mm switch cutouts on a 19.05 mm grid |
The PCB rests on a 3.5 mm wide ledge that runs around the inside of the tray, and is held by 4x M3 screws that come in from underneath.
Three openings:
- USB-C — 13 mm wide cutout in the wall next to the XIAO. The connector overhangs the edge of the PCB by 1.2 mm, so the cutout goes through the full thickness of the wall.
- Rotary encoder — 13.5 x 12.5 mm cutout in the top plate. The EC11 body is 12 x 11.6 mm and taller than the gap under the plate, so the whole body has to pass through it; a round hole would have to be 16.7 mm across to clear the same body, which is why this one is rectangular. The knob covers it.
- XIAO — window in the top plate, which keeps the BOOT button reachable without opening the case.
Images
Schematic
PCB
Case
From the top, with the top plate in place. The switch cutouts, the encoder cutout and the window over the XIAO all look through onto the PCB, which sits inside the tray:
The whole thing at an angle — the tray, the wall around the PCB and the USB cutout in it:
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| Seeed XIAO RP2040 | 1 | main microcontroller |
| Cherry MX compatible switch | 12 | plate mount |
| 1u keycap | 12 | |
| 1N4148 diode | 12 | DO-35, through-hole |
| EC11 rotary encoder | 1 | with push button |
| Encoder knob | 1 | |
| M3 screw | 4 | |
| Custom PCB | 1 | 94.5 x 94.0 mm, 2 layers |
| 3D printed top plate | 1 | 1.5 mm |
| 3D printed tray | 1 | 8 mm floor with a 3 mm recess, 2 mm wall around the PCB |
Firmware
The firmware is written in KMK, which runs on CircuitPython.
To flash it:
- Put the XIAO RP2040 into bootloader mode (hold BOOT while plugging it in).
- Drag the CircuitPython
.uf2onto theRPI-RP2drive that appears. - Copy the
kmkfolder from the KMK repository onto theCIRCUITPYdrive. - Copy
Firmware/main.pyonto theCIRCUITPYdrive.
Editing the keymap only means editing main.py and saving it — no compiling.
Repository layout
| Folder | Contents |
|---|---|
CAD/ | complete case model in STEP format, including the PCB |
PCB/ | KiCad project: schematic, board and footprint library |
Firmware/ | KMK firmware source |
Production/ | everything needed to actually make one: STLs, firmware, gerbers |
images/ | screenshots used in this README |
Production files
Production/ holds the files you send to a fab house or a printer:
| File | What it is |
|---|---|
gerbers.zip | 2 copper layers, both silkscreens, both solder masks, edge cuts, and separate PTH/NPTH Excellon drill files |
Bottom plate.stl | the tray, 99.5 x 99.0 x 13 mm |
Top plate.stl | the top plate |
firmware/ | CircuitPython .uf2 for the XIAO RP2040, plus the kmk library and main.py that go onto the CIRCUITPY drive |
KMK runs on CircuitPython, so there is no binary to compile — the .uf2 is the
runtime and the two Python files are the keyboard. Together they are the
flashable firmware.
Parts
31| Qty | Value | Footprint | References |
|---|---|---|---|
| 12 | D | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12 |
| 12 | SW_Push | Button_Switch_Keyboard:SW_Cherry_MX_1.00u_PCB | SW2, SW3, SW4, SW5, SW6, SW7, SW8, SW9, SW10, SW11, SW12, SW13 |
| 1 | LOGO | footprints:flaga3 | G*** |
| 1 | MOUDLE-SEEEDUINO-XIAO | footprints:XIAO-Generic-Hybrid-14P-2.54-21X17.8MM | U1 |
| 1 | RotaryEncoder_Switch | Rotary_Encoder:RotaryEncoder_Alps_EC11E-Switch_Vertical_H20mm | SW1 |
The 27 most common of 31 parts.
Questions
How big is the Slackpad PCB?
It measures 94.5 × 94 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Slackpad use?
31 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 Slackpad KiCad files?
From the faded-debug/Slackpad repository on GitHub, at the commit this page was made from: the board is PCB/Slackpad.kicad_pcb and its schematic PCB/Slackpad.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Slackpad design in my own project?
Its repository states no licence, so its author keeps all rights: ask faded-debug before reusing the design.
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