4 layers99 × 53.3 mm
PSLab
fossasia/pslab-hardware
PSLab Hardware Design and Schematics https://pslab.io
199 parts1.7kApache-2.0
2 layers99.5 × 81 mm
Hackpad 3.0
6255127/Hack-PadA custom 3x4 macro keyboard I built from scratch - schematic, PCB, 3D printed case, and firmware, all done by me as a portfolio/hackathon project.
- Size
- 99.5 × 81 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 28
- Nets
- 42
- Pads
- 133
- Tracks, vias
- 213, 0
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 1 Jul 2026
- Updated
- 6 Jul 2026
Overview
Hackpad 3.0 is an open-source printed circuit board by 6255127, from the 6255127/Hack-Pad repository on GitHub. It is a 2-layer board of 99.5 × 81 mm with 28 parts on 42 nets, routed with 213 tracks and 0 vias.
It is built around the WS2812B. Its parts include 13 diodes, 13 switches and 1 IC. It belongs with the RP2040 and AVR (ATmega, ATtiny) boards of this library.
Main components
1README
README.mdHackpad
A custom 3x4 macro keyboard I built from scratch - schematic, PCB, 3D printed case, and firmware, all done by me as a portfolio/hackathon project. Built around an Arduino Nano RP2040 Connect, with a rotary encoder, OLED status screen, and per-key RGB backlighting.
Features
- 3x4 key matrix (12 keys)
- rotary encoder for scroll/navigation
- 0.91" OLED showing current layer, last key pressed, and time (synced over wifi)
- SK6812 addressable LEDs under each key
- two layers - numpad mode and a shortcuts mode (copy/paste/undo/save/etc)
- wired usb keyboard (bluetooth planned later, board already supports it)
1. Schematic
Designed in KiCad. Went through a few pin conflicts along the way (accidentally put the LED data line on the I2C bus at one point) before landing on the final wiring.
2. PCB routing
Routed as a 2-layer board - rows on the bottom copper, columns on top, vias where they cross. Ran into a mixed-up switch numbering issue during routing that caused some real weird ratsnest jumps, fixed by re-checking every switch against the row/column table by hand.
3. 3D case
Modeled in Fusion 360 / Onshape, sandwich-mount style. Bottom half holds the PCB and MCU, top half is the switch plate with cutouts for keycaps, the encoder, and the OLED window. Top plate designed to be printed in clear/frosted material so the LEDs glow through it.
4. Firmware
Written in Arduino for the Nano RP2040 Connect. Handles matrix scanning, encoder input, LED feedback, OLED display, and layer switching (numpad vs shortcuts) via the encoder click.
To-do
- bluetooth (board already has the chip, just needs the firmware side)
- battery + charging circuit
- silkscreen art on the back
Parts
28| Qty | Value | Footprint | References |
|---|---|---|---|
| 12 | 1N914 | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12 |
| 12 | SW_Push_45deg | Button_Switch_Keyboard:SW_Cherry_MX_1.00u_PCB | SW1, SW2, SW3, SW4, SW5, SW6, SW7, SW8, SW9, SW10, SW11, SW12 |
| 1 | Arduino_Nano_RP2040_Connect | Module:Arduino_Nano_WithMountingHoles | A1 |
| 1 | ER_OLEDM0.91_1x-I2C | Display:ER_OLEDM0.91_1x-I2C | U1 |
| 1 | RotaryEncoder_Switch | Rotary_Encoder:RotaryEncoder_Alps_EC11E-Switch_Vertical_H20mm | SW13 |
| 1 | WS2812B | LED_SMD:LED_WS2812B-Mini_PLCC4_3.5x3.5mm | D15 |
Questions
How big is the Hackpad 3.0 PCB?
It measures 99.5 × 81 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Hackpad 3.0 use?
28 parts, built around the WS2812B. 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 Hackpad 3.0 KiCad files?
From the 6255127/Hack-Pad repository on GitHub, at the commit this page was made from: the board is PCB/hackpad 3.0.kicad_pcb and its schematic PCB/hackpad 3.0.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Hackpad 3.0 design in my own project?
Its repository states no licence, so its author keeps all rights: ask 6255127 before reusing the design.
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