# Gemma Translator > Source: > Published: 2026-08-11 14:29:51+00:00 This repo was built with the assistance of [Google Antigravity](https://antigravity.google/) and includes code to run an on-device, fully offline voice translator powered by [Gemma 4](https://ai.google.dev/gemma/docs/core) and [LiteRT-LM](https://github.com/google-ai-edge/LiteRT-lm). This project features a web frontend optimized for small handheld displays (e.g., 480x320) and a Python API server (`http.server` ) that communicates with Gemma. Text-to-speech is powered by [Moonshine](https://github.com/moonshine-ai/moonshine). ## demo.mp4 **On-Device Inference**: Uses LiteRT-LM to run the`gemma4-e2b` model entirely locally. No internet required after setup.**Voice Interface**: Captures microphone audio, processes it, and sends it to the local model.** Optimized UI**: Retro-terminal styling custom-built for small hardware screens (like Raspberry Pi displays).** Unified Startup**: One script to launch the LLM server, the Python API, and the React frontend. - Python 3.10+ - Node.js 18+ (20 LTS recommended) & npm — installed automatically by `deploy-pi.sh` on Raspberry Pi OS / Debian - Linux or macOS **Compute**: Raspberry Pi 5 with 8GB RAM** Audio Input**: Microphone or USB audio capture interface** Audio Output**: Speaker or headphone output device** Display**: Display monitor or touchscreen (e.g., 480x320 kiosk display) - **Make Scripts Executable** Ensure the setup, download, start, and deployment scripts have execute permissions: ``` chmod +x setup.sh download_model.sh start.sh deploy-pi.sh ``` - **Install Dependencies** Run the setup script to create a Python virtual environment (`venv` ) and install all required packages: ``` ./setup.sh ``` - **Download the Model** Run the model downloader script to fetch the`gemma4-e2b` model from Hugging Face and import it into LiteRT-LM: ``` ./download_model.sh ``` Start all services (LiteRT-LM, the Python API server, and the Vite Web UI) in development mode: ``` ./start.sh ``` To run in production mode (skipping Vite dev server and serving compiled UI assets from `frontend/dist/` via `backend/server.py` on port 3000): ``` ./start.sh --prod ``` The application will be accessible at: **Web UI (Dev)**:`http://localhost:5173` **Web UI (Prod) / API server**:`http://localhost:3000` **LiteRT-LM**:`http://localhost:9379` To deploy as a permanent systemd kiosk service on a Raspberry Pi 5 (8GB): ``` ./deploy-pi.sh ``` This automated script installs Debian audio/venv packages, sets up the Python environment, builds production UI assets, downloads the LiteRT model, registers the systemd unit from `deploy/gemma-translator.service` , and configures LXDE GUI autostart (`~/.config/lxsession/rpd-x/autostart` ) to launch Chromium in kiosk mode pointing to `http://localhost:3000` . `frontend/` - React (Vite) web frontend (`index.html` ,`src/` , styles, and Vite configuration).`backend/` - Python API server (`server.py` and`requirements.txt` ) for Moonshine STT, moonshine-voice TTS, and model proxying.`deploy/` - Parameterizable systemd service unit template (`gemma-translator.service` ).`stl/` - STL files for 3D printing the hardware case.`setup.sh` - Automates Python virtual environment creation and dependency installation.`download_model.sh` - Fetches the required LiteRT model.`start.sh` - Multi-process launcher supporting`--prod` and development modes.`deploy-pi.sh` - One-command Raspberry Pi automated deployment script. The Gemma Translator supports **two keyboard modes**. Switch between them anytime from the **Settings panel → "Keyboard Mode"** dropdown. The choice is remembered across restarts (stored in the browser's `localStorage` under the key `keyboardMode` ). The app has two lanes (two people facing each other on the kiosk): **Lane 1 / Person 1**— the left/top lane.** Lane 2 / Person 2**— the right/bottom lane. Each lane has a rotating language "revolver" and records speech, which is transcribed (Moonshine STT), translated (Gemma), and spoken back in the other lane's language (moonshine-voice TTS). One lane is the **active person** at a time. The active lane is framed with **corner brackets on all four corners**. You drive everything from a single set of keys and switch focus with Space. | Key | Action | Description | |---|---|---| Spacebar | Switch active person | Toggles the active lane (Person 1 ⇄ Person 2). Disabled while recording. | Z | Record (push-to-talk) | Hold to record the active person; release to transcribe & translate. | ← Left Arrow | Previous language | Rotates the active person's language backward. | → Right Arrow | Next language | Rotates the active person's language forward. | Notes: - The active lane shows four-corner brackets; while it is recording, the brackets invert to black along with the lane's color reversal. - Best for one-handed / single-operator use. Each lane has its **own dedicated keys** — there is no active-person concept and **no bracket highlight**. Both people can be controlled independently. | Key | Action | Description | |---|---|---| Z | Record — Person 1 (push-to-talk) | Hold to record Lane 1; release to transcribe & translate. | X | Record — Person 2 (push-to-talk) | Hold to record Lane 2; release to transcribe & translate. | ← Left Arrow | Previous language — Person 1 | Rotates Lane 1's language backward. | → Right Arrow | Next language — Person 1 | Rotates Lane 1's language forward. | − Minus (`_` ) | Previous language — Person 2 | Rotates Lane 2's language backward. | + Plus (`=` ) | Next language — Person 2 | Rotates Lane 2's language forward. | Notes: - No corner-bracket selection highlight in this mode. - Best for two operators, each handling their own side. **Input focus guard:** all shortcuts are ignored while focus is on a configuration field (`` ,`