Project 5: The Full Stack “XiaoZhi” Clone
- File:
05_full_stack_xiaozhi.md- Main Programming Language: C (ESP-IDF)
- Coolness Level: Level 5: Pure Magic
- Difficulty: Level 4: Expert
- Knowledge Area: System Architecture / Full Duplex Audio
- Software: Websockets, Opus Encoding, Specialized Firmware
What you’ll build: A complete, standalone voice assistant that mimics the official XiaoZhi firmware. It listens for a wake word, records audio, streams it (compressed via Opus) to a server (or direct to API), receives an audio stream back, and plays it—all in real-time with interruptibility (you can cut it off while it’s talking).
Why it teaches Architecture: This combines everything: multitasking, double-buffering audio, network streaming, and state management. This is “production grade” firmware engineering.
Core challenges you’ll face:
- Full Duplex Logic: Handling “Listening” and “Speaking” states. What if the user speaks while the bot is speaking? (AEC - Acoustic Echo Cancellation).
- Opus Compression: Raw audio is too slow for some networks. You’ll implement Opus encoding to squeeze audio data.
- Latency Optimization: Shaving milliseconds off every step to make it feel “human”.
Real World Outcome: You have a conversation. “XiaoZhi, what is the weather?” -> “It is sunny.” -> “And what about tomorrow?” -> “Tomorrow will be…” It remembers context (if you code the backend right) and feels like a real product.
Project Comparison Table
| Project | Difficulty | Time | Depth of Understanding | Fun Factor |
|---|---|---|---|---|
| 1. The Eye | Low | Weekend | Graphics & Memory | ⭐⭐⭐ |
| 2. The Parrot | High | 1 Week | Low-level Audio & DMA | ⭐⭐ |
| 3. Dumb Chatbot | Med | Weekend | HTTPS & APIs | ⭐⭐⭐ |
| 4. HA Satellite | Med | Weekend | IoT Ecosystems | ⭐⭐⭐⭐⭐ |
| 5. Full Clone | Very High | 1 Month+ | System Engineering | ⭐⭐⭐⭐⭐ |
Recommendation
Start with Project 4 (ESPHome Satellite). Why? It gives you an immediate “Quick Win”. You get the board working, the screen drawing, and the microphone listening within hours. It validates your hardware is working (not broken).
Then, move to Project 1 & 3 if you want to learn coding (C++). Move to Project 5 only if you want to become an embedded systems engineer.
Final Overall Project: The “Offline-First” Privacy Bot
Project: The Local Command Center Combine the ESP32-S3 with a local server (like a PC running Ollama + Whisper).
- Wake Word: Runs on ESP32 (using “ESP-SR”).
- Speech-to-Text: Stream audio to local PC (Whisper).
- Brain: Local Llama 3 / Mistral model on PC.
- Text-to-Speech: Local Piper TTS on PC, streamed back to ESP32.
Why?: Zero latency (local network), Zero privacy concerns (no cloud), Zero subscription costs. You build the ultimate private assistant.
Summary
This learning path covers the XiaoZhi ESP32-S3 Robot through 5 hands-on projects.
| # | Project Name | Main Language | Difficulty | Time Estimate |
|---|---|---|---|---|
| 1 | The “Eye” (Display) | C++ (Arduino/LVGL) | Beginner | Weekend |
| 2 | The Parrot (Audio) | C (ESP-IDF) | Advanced | 1 Week |
| 3 | Dumb Chatbot (API) | C++ | Intermediate | Weekend |
| 4 | HA Satellite | YAML (ESPHome) | Intermediate | Weekend |
| 5 | Full Stack Clone | C (ESP-IDF) | Expert | 1 Month+ |
Recommended Learning Path
For IoT Enthusiasts: Project #4 -> Enjoy your smart home. For Programmers: Project #1 -> #3 -> #2 -> #5.
Expected Outcomes
After completing these projects, you will:
- Understand DMA & PSRAM usage in the ESP32-S3.
- Master I2S Audio pipelines (Recording and Playback).
- Know how to drive Round Circular Displays.
- Build real-world Voice-to-LLM integrations.