
OSO SWAT B1-jig
joeycastillo/Sensor-Watch
A board replacement for the classic Casio F-91W wristwatch

HackPad is a custom-built 9-key macropad featuring a rotary encoder, an OLED display, a custom-designed PCB, and a fully 3D-printed enclosure.
HackPad is an open-source printed circuit board by Tanmay-1122, from the Tanmay-1122/HackPad repository on GitHub. It is a 2-layer board of 96 × 94.5 mm with 31 parts on 24 nets, routed with 202 tracks and 5 vias.
Its parts include 10 switches, 9 diodes and 2 ICs.
HackPad is a custom-built 9-key macropad featuring a rotary encoder, an OLED display, a custom-designed PCB, and a fully 3D-printed enclosure.
The project was designed from scratch, including the schematic, PCB layout, custom PCB artwork, enclosure, and firmware.


The PCB was designed in KiCad and contains the complete hardware for the HackPad, including the 3×3 switch matrix, rotary encoder, OLED display, and Seeed Studio XIAO RP2040.
The front of the PCB contains the main components and custom silkscreen artwork, including the Hack Club flag and other design elements.

The back of the PCB features large custom monochrome artwork integrated directly into the PCB silkscreen.
| Component | Quantity |
|---|---|
| Seeed Studio XIAO RP2040 | 1 |
| Mechanical switches | 9 |
| Keycaps | 9 |
| Rotary encoder | 1 |
| 0.91-inch I2C OLED display | 1 |
| Diodes | 9 |
| Custom PCB | 1 |
| 3D-printed top enclosure | 1 |
| 3D-printed bottom enclosure | 1 |
| M3 screws | 6 |
| M3 heat-set inserts | 6 |
The firmware is written in CircuitPython and is located in:
Firmware/main.py
The firmware handles the 9 mechanical switches, rotary encoder, OLED display, and macropad functionality.
To use the firmware, install CircuitPython on the XIAO RP2040 and copy the required libraries and main.py to the board.
HackPad/
├── CAD/
│ └── Hackpadoverall.step
│
├── Firmware/
│ └── main.py
│
├── PCB/
│ ├── Hackpad.kicad_pcb
│ ├── Hackpad.kicad_pro
│ └── Hackpad.kicad_sch
│
├── Production/
│ ├── Bottom.stl
│ ├── Top.stl
│ ├── gerbers.zip
│ └── main.py
│
├── images/
│ ├── caseback.png
│ ├── caseside.png
│ ├── casetop.png
│ ├── pcbback.png
│ └── pcbtop.png
│
└── README.md| Qty | Value | Footprint | References |
|---|---|---|---|
| 9 | 1N4148 | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D1, D2, D3, D4, D5, D6, D7, D8, D9 |
| 9 | SW_Push | Button_Switch_Keyboard:SW_Cherry_MX_1.00u_PCB | SW1, SW2, SW3, SW4, SW5, SW6, SW7, SW8, SW9 |
| 7 | LOGO | LOGO | G***, G***, G***, G***, G***, G***, G*** |
| 1 | ER_OLEDM0.91_1x-I2C | Display:ER_OLEDM0.91_1x-I2C | U2 |
| 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_CircularMountingHoles | SW10 |
The 28 most common of 31 parts.
It measures 96 × 94.5 mm and has 2 copper layers, 1.6 mm thick.
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.
From the Tanmay-1122/HackPad repository on GitHub, at the commit this page was made from: the board is PCB/Hackpad.kicad_pcb and its schematic PCB/Hackpad.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Its repository states no licence, so its author keeps all rights: ask Tanmay-1122 before reusing the design.

joeycastillo/Sensor-Watch
A board replacement for the classic Casio F-91W wristwatch

hoglet67/RGBtoHDMI
Bare-metal Raspberry Pi project that provides pixel-perfect sampling of Retro Computer RGB/YUV video and conversion to HDMI

hackclub/OnBoard
💡 Join 1,000 teenagers and make your first PCB with a $100 grant!

openwch/ch32v003
CH32V003 is an ultra-cheap RISC-V MCU with 2KB SRAM, 16KB flash, and up to 18 GPIOs that sells for under $0.10

Luos-io/luos_engine
Open-source and real-time orchestrator for cyber-physical-systems, to easily design, test and deploy embedded applications and digital twins.
BlueAndi/Pixelix
Full RGB LED matrix, based on an ESP32 and WS2812B LEDs or emulated LEDs on TFT.

