朋友 Game Boy Color 被偷后，我用 Gemma 3 4B 做了个浏览器版

Hacktoberfest Weekend Challenge: Build for a Friend Submission 🤝

This is a submission for the Hacktoberfest Weekend Challenge: Build for a Friend

My friend's Game Boy Color got stolen. Rude. Then he went looking for a replacement and found out that decent used ones are now rare, overpriced, or "mint condition" in the way that means "mint-flavored lie."

So I built him a new one that can't be stolen: a Game Boy Color in the browser. It's teal, it has a D-pad that clicks, and it plays real Game Boy games.

The twist is that he never has to scroll through a ROM list. He just tells it what he's in the mood for:

"I want to play a game involving Pokémon."

A small AI reads the request, picks a game from the collection, and boots it. He can type the request or tap the mic and say it out loud. A bit like a game store clerk who lives inside the console.

Demo

Code

Browser-based Gameboy Color Emulator

with AI game search capabilities using Google gemma 4b

Note: For the AI feature to work you need to have https://ollama.com/library/gemma3:4b installed and running on your machine.

in the package.json file there is a script called "start:ai" which will start the ollama server.

How I Built It

Emulator: The mGBA core compiled to WebAssembly, wired up in a Vite + TypeScript project. It loads ROMs straight from public/gameroms, including ones packed inside ZIP files.
Controls: Keyboard (Z/X/Enter/Shift), touch buttons on the on-screen console, and gamepad support.
The AI picker: Gemma 3 (4B), running locally through Ollama. When he makes a request, the app sends it along with the list of available games. Gemma picks the best match and the emulator loads it.
Voice: The browser's built-in speech recognition fills in the prompt and submits it when he stops talking. It's not an AI model, but it makes the whole thing feel like magic.
Escape hatch: If he knows what he wants, "Choose a game instead" opens a normal list.

The prompt is simple: "here's what the player wants, here's the game list, pick one." The game list is just a file (src/games.ts), so adding a game means dropping a ROM in a folder and adding its name.

Why Does Open Innovation Matter?

This project needed an AI that could do one small job well: match a vibe to a filename. A giant cloud model would be overkill, and a cloud API would have made it worse in a few ways:

It costs nothing. No API key, no per-request bill, no "you've hit your limit" while someone is trying to play Pokémon. For a gift to a friend, that matters.
It runs locally. His requests never leave the machine. Nobody needs to know what he plays at 2 AM.
It's swappable. Gemma 3 4B was small and fast enough. If a different model picks better, it's one line to change.
It doesn't break on me. No deprecation emails, no pricing changes, no surprise outages. The model is on the disk, and it stays there.

A 4B open model on a normal machine turned out to be plenty for this. It does the job without anyone's permission or a credit card.

Prize Categories

Best Use of Gemma: Gemma 3 (4B) running locally through Ollama powers the natural-language game picker.