Choco

A voice-powered language tutor for kids.

This repo contains two products that share a common core:

Product	Description	Target
chocopi	Always-on kiosk app with on-device wake word detection	Raspberry Pi (dedicated device)
chocoweb	Browser-accessible server app with WebRTC audio	Any host, accessed from any browser

Both apps consume chococore — the platform-agnostic package that handles conversation logic, LLM providers, session memory, and prompts.

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chocopi — Raspberry Pi Kiosk

ChocoPi listens for a wake word, then holds a live conversation to help children practice English, Korean, Spanish, or Chinese. Each language has its own wake word, sleep word, and teaching style — all configurable.

chocopi-demo.mp4

How It Works

1. Wake word detection runs on-device using OpenWakeWord (TFLite on ARM, ONNX elsewhere)
2. Once triggered, a live voice conversation starts via a configurable provider (OpenAI Realtime, Gemini Live, or Ultravox)
3. The assistant adapts to the child's age, native language, and comprehension level
4. Sessions end with a language-specific sleep word or timeout
5. Conversation history is summarized and persisted for continuity across sessions

Features

• 4 languages — English, Korean, Spanish, and Chinese
• On-device wake words — "Hey Choco", "Anyeong Choco", "Hola Choco", "Nihao Choco"
• Multiple voice providers — OpenAI Realtime (default), Google Gemini Live, or Ultravox; swap via config.yml
• User profiles — per-child age, native language, and learning levels
• Session memory — remembers jokes, vocab, topics, and progress across conversations
• Display support — animated character and live transcript panel (pygame-ce); also works headless!

Requirements

• Microphone and speaker (Bluetooth or wired)
• API key for your chosen voice provider (OpenAI by default — see pricing)
• Python 3.11 (required — tflite-runtime has no wheels for 3.12+)

Raspberry Pi Setup

Tested on Raspberry Pi 4+ with 64-bit Raspberry Pi OS Lite (Trixie and Bookworm).

1. Flash Raspberry Pi OS Lite (64-bit) with rpi-imager (configure user, SSH, WiFi)

2. SSH into your Pi and run:

   bash <(curl -fsSL https://raw.githubusercontent.com/codesmax/choco/main/pi/install.sh)

   Or clone first:

   git clone https://github.com/codesmax/choco.git
   cd choco
   ./pi/install.sh

   The installer handles system dependencies, audio stack setup, Python environment, and systemd service creation.

macOS Setup

bash <(curl -fsSL https://raw.githubusercontent.com/codesmax/choco/main/pi/install.sh)

Or clone first and run locally:

git clone https://github.com/codesmax/choco.git
cd choco
./pi/install.sh

Manual Setup (Linux / macOS / Windows)

git clone https://github.com/codesmax/choco.git
cd choco

# Install uv if needed
pipx install uv

# macOS: also install portaudio
brew install portaudio

# Set up workspace (creates .venv and installs all packages)
uv sync

# Configure
cp .env.example .env       # add your API key
vi config.yml              # set profile, provider, languages, etc.

# Run
./pi/chocopi/chocopi

Note: On Windows, skip the bash launcher and run directly with python -m chocopi instead. WSL is also an option.

Configuration

All settings live in two files:

File	Contents
.env	API key(s) — OPENAI_API_KEY, GOOGLE_API_KEY, ULTRAVOX_API_KEY
config.yml	Profiles, languages, provider, wake/sleep words, prompts, audio settings, display settings

Voice Provider

Set provider in config.yml to switch between backends:

Provider	provider value
OpenAI Realtime	openai (default)
Google Gemini Live	google
Ultravox	ultravox

Profiles

Profiles let multiple users share one device. Each profile specifies age, native language, and learning languages with comprehension levels. Set profile in config.yml to switch.

Bluetooth Audio

# Pair your device
sudo -u chocopi bluetoothctl
scan on
pair <MAC_ADDRESS>
trust <MAC_ADDRESS>
connect <MAC_ADDRESS>
exit

# Restart WirePlumber and ChocoPi
sudo -u chocopi XDG_RUNTIME_DIR=/var/run/user/$(id -u chocopi) systemctl --user restart wireplumber
sudo systemctl restart chocopi

Service Management (Pi)

sudo systemctl start chocopi    # Start
sudo systemctl stop chocopi     # Stop
sudo systemctl status chocopi   # Check status
sudo journalctl -u chocopi -f   # View logs

Development

CHOCO_LOG_LEVEL=DEBUG ./pi/chocopi/chocopi    # verbose logging
CHOCO_DISPLAY=0 ./pi/chocopi/chocopi          # disable pygame-ce UI

Audio Debugging

python -m sounddevice              # list audio devices
pactl list sinks short             # list output devices (Linux)
pactl list sources short           # list input devices (Linux)
wpctl status                       # PipeWire/WirePlumber status
bluetoothctl                       # manage Bluetooth connections
sudo journalctl -u chocopi -f      # service logs on Pi

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Repo Structure

choco/                          # uv workspace root
├── pyproject.toml              # workspace definition (members: core, pi)
├── config.yml                  # runtime configuration (shared)
├── assets/
│   ├── models/                 # wake-word models (.tflite + .onnx)
│   ├── images/                 # character sprites, UI elements
│   ├── sounds/                 # SFX and jingles
│   └── fonts/                  # bundled fonts
├── core/
│   └── chococore/              # platform-agnostic package
│       ├── config.py           #   config + env loading, path constants
│       ├── conversation.py     #   Pipecat pipeline + turn logic (transport-injected)
│       ├── providers.py        #   LLM service factories (OpenAI, Gemini, Ultravox)
│       ├── memory.py           #   session memory persistence
│       └── pipecat_utils.py    #   FrameProcessor subclasses + observer
├── pi/
│   ├── chocopi/                # Pi kiosk package
│   │   ├── chocopi             #   bash launcher (entry point)
│   │   ├── chocopi.py          #   orchestrator + signal handling
│   │   ├── wakeword.py         #   OpenWakeWord integration
│   │   ├── audio.py            #   audio I/O (sounddevice + simpleaudio)
│   │   └── display.py          #   optional pygame-ce UI
│   └── install/                # Pi-specific installation
│       ├── install.sh          #   cross-platform installer
│       ├── systemd/            #   systemd service unit
│       ├── wireplumber/        #   Bluetooth audio configs
│       └── pipewire/           #   echo cancellation config
└── data/                       # per-profile memory files (gitignored)

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Known Issues

• Wake word false activations — nearby environmental noise can trigger false activations. Limit supported languages to those in use and keep the mic away from TVs and other continuous audio sources.
• Python 3.11 only — tflite-runtime (required by OpenWakeWord) has no wheels for Python 3.12+. Upstream limitation with no current workaround.
• Windows — works, but the bash launcher isn't usable; run python -m chocopi directly or use WSL.
• Bluetooth mic dropouts — if the mic stops working after a reboot, the device may have reverted to A2DP. Re-connect and confirm HSP/HFP via bluetoothctl.

Roadmap

• chocoweb UI improvements
• Support remote deployment of chocoweb (authentication, NAT traversal)
• Support tool calling for image display during instruction

Contributing

Contributions are welcome. A few good starting points:

• Add a language — add an entry under languages in config.yml with a wake word, sleep word, and model name. Wake word models (.onnx / .tflite) come from OpenWakeWord.
• Improve tutor prompts — the prompts section in config.yml drives all tutor behavior and is easy to iterate on without touching Python.
• Bug reports / feature requests — open an issue on GitHub.

See AGENTS.md for architecture notes, key files, and change guidelines.

License

MIT