Introduction
Imagine carrying the iconic Nintendo GameCube in your pocket—not as a full-sized console, but as a fully functional keychain. Thanks to the Nintendo Kawaii project, a group of dedicated modders has managed to shrink the boxy GameCube down to a tiny, portable form factor using genuine Nintendo silicon. The design includes a custom dock for connectivity and is shared openly on GitHub for enthusiasts to replicate. This how-to guide will walk you through the process of building your own keychain-sized GameCube, from sourcing original Nintendo components to assembling the miniature system. Whether you're a seasoned hardware hacker or a curious beginner, these steps will help you bring this remarkable mod to life.
What You Need
Essential Components
- Genuine Nintendo GameCube motherboard (preferably a trimmed, smaller revision for easier fitting)
- Nintendo silicon chips (CPU, GPU, and memory controller) – must be sourced from an original GameCube to ensure authenticity
- Custom PCB or breakout boards for interconnecting the chipset
- Small OLED or LCD screen (compatible with GameCube’s native video output, e.g., using a GCVideo adapter)
- Keychain-friendly enclosure (3D-printed case based on the GitHub files)
- USB-C or similar connector for power and dock interface
- Dock unit (provided in the GitHub design; includes HDMI, USB, and controller ports)
- Lithium-polymer battery (3.7V, capacity based on your power needs)
- Power management module (e.g., Adafruit PowerBoost or similar)
Tools
- Soldering iron with fine tip
- Hot air rework station (for removing chips from donor board)
- 3D printer (or access to a printing service)
- Multimeter
- Small screwdrivers, tweezers, and a magnifying lamp
- Flux, solder wick, and high-quality solder
- Micro USB cable for testing
Step-by-Step Instructions
Step 1: Research and Download the Design
Start by visiting the official Nintendo Kawaii GitHub repository. Fork or download the latest release to get the enclosure 3D models, circuit schematics, and bill of materials. Thoroughly read the project’s README and any documentation—this will save you from costly mistakes later. Pay special attention to the dock design, as it’s an integral part of the system.
Step 2: Source Genuine Nintendo Silicon
The heart of the keychain GameCube must be authentic Nintendo components. Obtain a donor GameCube (any region) and carefully desolder the main CPU, GPU, and memory controller using a hot air station. You can also purchase pre-removed chips from reputable retro gaming salvage stores. Verify each chip’s markings against the GitHub documentation to ensure you have the correct revisions.
Step 3: Prepare the Custom PCB
Order the PCB from the gerber files provided in the GitHub repository. If you’re designing your own, replicate the exact pad layout for the Nintendo chips. Once the boards arrive, inspect for short circuits and apply solder paste on the chip pads. Use a stencil if available to keep the paste consistent. Reflow the board in a toaster oven or with a hot air station, then check continuity with a multimeter.
Step 4: Assemble the Core System
Solder the Nintendo CPU, GPU, and memory controller onto the PCB following the orientation markings. Attach the OLED/LCD screen to the video output header—use a GCVideo board if the native video signal needs conversion. Connect the battery and power management module according to the schematic. Add the USB-C port for charging and data. Before sealing the case, test the board by powering it from a bench supply (3.3V and 1.8V rails) and verifying that the screen displays a BIOS or startup screen.
Step 5: Print and Modify the Enclosure
Use a high-resolution SLA or FDM printer to fabricate the keychain case and dock housing from the provided STL files. Sand and smooth the parts if needed. The enclosure should have precise cutouts for the screen, button holes, and the USB port. Also print the dock’s base—this holds HDMI and controller ports. Apply a thin layer of superglue or epoxy to reinforce thin sections, especially where the keychain ring attaches.
Step 6: Wire the Controls and Dock
Solder the GameCube controller port pins (data lines, power, ground) to corresponding pads on the main board. The dock includes a USB hub for external controllers—connect these lines to the GameCube’s controller interface. For video output, route the RGB or YPbPr signals from the GCVideo board to the dock’s HDMI transmitter module. Ensure proper impedance matching for video to avoid signal degradation.
Step 7: Final Assembly and Testing
Place the populated PCB inside the enclosure, securing it with small screws or standoffs. Insert the screen, buttons, and keychain ring. Close the case halves and test all functions: power on, load a game from an SD gecko adapter (if you’ve integrated that), check display output, and verify controller inputs through the dock. Use the dock to connect to a TV to confirm video and audio work. If everything passes, seal the case permanently or use a small screw for battery access.
Tips for Success
Handle static-sensitive parts with care – Nintendo’s silicon is ESD-sensitive; always use a grounded mat and wrist strap.
Start with a known-good donor board – Test the GameCube fully before harvesting chips to avoid wasting time on dead components.
Consider a microSD card slot – For loading games without original discs, add an SD gecko mod (schematics may be in the GitHub repo).
Use a heat sink on the CPU – Even in a tiny case, the chip can get warm; a small copper shim and thermal pad improve reliability.
Double-check polarity – Reversing battery connections can destroy the power module instantly.
Update firmware – If the project includes an FPGA or microcontroller for video conversion, flash the latest firmware from GitHub.
Join the community – The Nintendo Kawaii Discord or subreddit often has troubleshooting tips and case design improvements.
With patience and careful soldering, you’ll have a fully functional keychain GameCube that’s a true conversation starter. The combination of genuine Nintendo hardware and a modern, compact enclosure makes this mod a triumph of retro engineering. Now go ahead and shrink your game collection—one keychain at a time!