A working controller the size of your thumb
In the quiet tradition of makers who find possibility where others see mere decoration, a creator known as Brux has transformed a GameCube novelty keychain into a fully functional pocket-sized controller — small enough to hold between two fingers, capable enough to play real games. Using an RP2040 microcontroller, surface-mount tactile switches, and 3D-printed internal components, he collapsed the distance between nostalgia and engineering. It is a reminder that constraints of scale need not be constraints of capability, and that the most interesting innovations sometimes begin with the humblest objects.
- A GameCube keychain — the kind of trinket that collects dust on a backpack zipper — has been rewired, hollowed out, and brought to life as a working game controller.
- The engineering challenge was immense: fitting tactile switches, custom 3D-printed mounts, and a capable microcontroller inside a shell the size of a thumb demanded both precision and patience.
- Skeptics had reason to doubt, but demonstration footage of the device successfully running Fortnite and Mario Kart Wii silenced the obvious objections.
- The project is already expanding outward — N64, SNES, and a miniature 3DS are all in development, each presenting its own distinct engineering puzzle.
- What began as a single novelty conversion is quietly becoming a broader argument: that retro hardware, reimagined at miniature scale, can still be fully, genuinely functional.
A creator named Brux has done something that looked impossible until he demonstrated otherwise: he took a GameCube novelty keychain and turned it into a working controller small enough to fit in a pocket. The device plays real games — Fortnite, Mario Kart Wii — without lag or missed inputs.
The build required hollowing out the keychain shell with a rotary tool, then designing and 3D-printing custom internal components to house the electronics. Surface-mount tactile switches handle button input, all wired carefully to an RP2040 microcontroller, which connects to the GameCube console via a single wire. The result is a fully functional controller that weighs almost nothing.
What distinguishes the project isn't merely that it works, but that it works without meaningful compromise. The buttons respond. The stick registers. The constraint of size did not become a constraint of capability.
Brux has already signaled what comes next: functional keychain controllers for the N64 and SNES, and an ambitious miniature 3DS. Each will demand its own engineering approach. But if the GameCube build is any measure, the question is no longer whether he can do it — only which console he reaches for next.
A YouTuber named Brux has done something that seemed impossible until he actually did it: he took a GameCube keychain—the kind of novelty item you buy at a gift shop and forget about—and turned it into a working controller small enough to fit in your pocket. The thing actually plays games. Fortnite. Mario Kart Wii. Real, playable games on a real console, using a controller the size of your thumb.
The build itself is a study in miniaturization and patience. Brux started with the hollow keychain shell and cleaned out its interior using a rotary motor, creating space for the actual electronics. He then designed and 3D-printed custom internal components to hold everything in place. For the buttons, he chose surface-mount tactile switches—tiny mechanical switches that register input when pressed. These are wired, with meticulous care, to an RP2040 microcontroller, a small but capable processor that handles all the input logic. A single wire runs from the RP2040 to the GameCube console itself, completing the circuit. The result is a fully functional controller that weighs almost nothing and takes up barely any space.
What makes this project noteworthy isn't just that it works—it's that it works *well*. In his demonstration video, Brux plays through actual game sequences without lag or missed inputs. The buttons respond. The stick registers movement. There's no compromise in functionality, only in size. You won't win a Super Smash Bros. Melee tournament with it, but that was never the point. The point was to prove that the constraint of space doesn't have to mean the constraint of capability.
Brux has already signaled that this is just the beginning. At the end of his video, he teases other projects in the works: a functional N64 controller keychain, a SNES controller keychain, and perhaps most ambitiously, a working 3DS in miniature form. Each of these would require its own engineering approach, its own custom parts, its own careful wiring. But if the GameCube controller is any indication, he's capable of pulling it off.
What's interesting about this kind of maker project is that it exists in a space between nostalgia and genuine innovation. The GameCube controller itself is now two decades old; the keychain version is a novelty item that's been around for years. But by combining off-the-shelf components like the RP2040 with custom 3D-printed parts and meticulous assembly, Brux has transformed something decorative into something functional. It's the kind of work that makes you reconsider what's possible when you're willing to spend the time and develop the skill. The next question isn't whether he can do it—it's which retro console he tackles next.
Citas Notables
Brux demonstrated the controller playing through actual game sequences without lag or missed inputs, proving the miniaturization doesn't compromise functionality.— Project demonstration video
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Why does this matter? It's a tiny controller. Surely the actual experience of playing on something that small would be frustrating.
You'd think so, but the videos show him actually playing through game sequences without issues. The buttons register, the stick responds. It's not about comfort—it's about proving the constraint doesn't have to exist.
So it's more about the engineering challenge than the practical use case.
Exactly. The practical use case is almost beside the point. What matters is that someone looked at a novelty keychain and asked: what if this was real? And then figured out how to make it real.
The RP2040 microcontroller—that's the key component here, right? That's what makes this possible?
It's one piece. The RP2040 is small and capable, sure, but the real work is in the 3D-printed housing, the tactile switches, the wiring. It's the integration of all those pieces into something that fits in your pocket.
And he's planning to do this for N64, SNES, and 3DS. Does each one get harder, or is the process repeatable once you've done it once?
Each console has different button layouts, different stick mechanisms, different power requirements. So yes, each one is its own puzzle. But he's proven he can solve the puzzle. Now it's just a matter of doing it again.