Romu is a compact USB Type-A development board powered by the Raspberry Pi RP2354A microcontroller. Inspired by projects like Tomu, Somu, and Fomu, Romu brings a modern twist with more performance, built-in interactivity and all in the same tiny form factor.

• Simply plug Romu into your computer’s USB port and start experimenting. With MicroPython support, RGB LED, and capacitive touch input, Romu makes embedded development fun, fast, and accessible for everyone—no cables, no external programmer required.

Make, Learn, and Prototype With Ease

Romu is designed to give you the versatility and power of the popular RP2354A chip in the smallest package possible. There is no carrier needed - simply plug it into any USB Type-A port and start developing! Whether you are a seasoned embedded developer or a beginner hoping to learn MicroPython, Romu is an incredibly approachable option that fits right on your keychain.

Beyond prototyping, its built-in capacitive touch button and RGB LED unlock a wide range of practical daily applications. For example, Romu can easily act as a Universal 2nd Factor (U2F) hardware token, just load compatible software (like Pico FIDO) and use it to securely authorize your two-factor authentication (2FA) logins. Alternatively, you can program it as a custom USB macro key to instantly mute your microphone during video calls, act as a one-touch password injector, function as a mouse jiggler to keep your PC awake, or use the RGB LED as a glowing status indicator for unread emails and system notifications.

Romu eliminates the clutter of wires and programmers, making it the perfect quick-start tool for makers, educators, and engineers.

Features & Specifications:

Core Hardware:

• MCU: Raspberry Pi RP2354A (Dual-core Arm Cortex-M33 @ 150 MHz)
• Memory: 264 KB SRAM, 4 MB Flash
• USB: Native USB 2.0 Full-Speed interface (via Type-A connector)
• Power: 5V from USB, regulated to 3.3V onboard
• Indicators: RGB LED
• Input: Capacitive touch button
• Control: Boot button for firmware flashing
• Programming: USB DFU or SWD test points
• Debugging: UART TX/RX test points

Physical Details

PCB Dimensions: 15.5 mm × 12 mm × 1.65 mm

Enclosure: 3D-printed shim (included and preinstalled)

Advanced Development with the Romu Jig

For advanced users and developers who need deeper access to the RP2354A microcontroller, we have designed a custom Programming and Debugging Jig. While Romu is perfectly capable as a standalone plug-and-play device, the Jig unlocks a comprehensive suite of hardware debugging tools.

The Jig features a dedicated placement area for the Romu board. To secure the device, simply place Romu onto the bed and rotate the knob located at the rear of the Jig. This rotation lowers the front hood, firmly sandwiching the Romu PCB into place.

Once secured, a set of precision pogo pins make contact with the test points on the Romu board, routing them to accessible ports on the Jig:

• USB Type-C Connectivity: Provides access to power and USB data lines through a USB Type-C port, allowing you to connect Romu to your PC without plugging the board directly into a Type-A slot.
• Hardware Debugging (SWD): Exposes the SWD interface through a standard 20-pin JTAG connector, enabling deep hardware debugging and flashing with external programmers.
• Serial Communication (UART): Provides dedicated pin breakouts for UART (RX & TX), allowing for seamless serial port monitoring and communication.

Open Source:

Romu is open hardware. All design files and documentation will be published on GitHub under open-source licenses before products are shipped to backers.

This will include:

• Schematics and PCB design files
• Bill of materials (BOM)
• 3D enclosure & Jig assembly STL files
• Example MicroPython scripts

Package Includes:

• 1 x Romu