add read me

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2026-01-09 10:28:44 +11:00
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# Voice Assistant Bridge (Docker Backend)
This repository contains the backend infrastructure for the local Voice Assistant system. It acts as the middleware between the ESP32 audio stream and Home Assistant.
## 🏗️ Architecture
```mermaid
graph LR
ESP32[ESP32 Hardware] -->|MQTT Audio Stream| Bridge
Bridge[Python Bridge] -->|HTTP Request| Whisper[Faster-Whisper Container]
Whisper -->|Text| Bridge
Bridge -->|MQTT Text Command| HA[Home Assistant]
Bridge -->|MQTT Status| ESP32
```
## 🧩 Components
### 1. `docker-compose.yml`
Orchestrates two containers:
* **`voice-bridge`**: The logic handler. Listens to MQTT audio, buffers it, detects Wake Words via `OpenWakeWord`, and handles routing.
* **`whisper-api`**: A lightweight Flask API wrapping `faster-whisper` for Speech-to-Text conversion.
### 2. `mqtt_audio_bridge.py`
The main Python script running inside the `voice-bridge` container.
* **Input:** Listens to raw PCM audio on `voice/audio_stream` (Broker .13).
* **Processing:**
* Uses **OpenWakeWord** to detect "Hey Jarvis".
* Buffers audio and sends to Whisper API.
* Safety mechanisms (Memory limits, Log rotation).
* **Output:** Publishes transcribed text to `homeassistant/voice/text` (Broker .30).
### 3. `app.py`
The Whisper API endpoint.
* **Model:** `small.en` (Optimized for CPU usage with `int8` quantization).
* **Language:** Locked to English to prevent hallucinations on static/silence.
## 🚀 Deployment
1. **Requirements:** Docker & Docker Compose.
2. **Configuration:** Update IP addresses in `mqtt_audio_bridge.py` for your MQTT brokers.
3. **Run:**
```bash
docker compose up -d
```
## 🔧 Debugging
**View Logs:**
```bash
docker compose logs -f voice_bridge
```
**Restart Stack:**
```bash
docker compose restart
```

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from flask import Flask, request, jsonify
from faster_whisper import WhisperModel
import os
import tempfile
app = Flask(__name__)
# Load Model
model_size = "small.en"
model = WhisperModel(model_size, device="cpu", compute_type="int8")
@app.route('/transcribe', methods=['POST'])
def transcribe_audio():
if 'audio' not in request.files:
return jsonify({"error": "No audio file provided"}), 400
audio_file = request.files['audio']
temp_file_path = None # Initialize variable
# Save file
with tempfile.NamedTemporaryFile(delete=False, suffix=".wav") as tmp_audio:
audio_file.save(tmp_audio.name)
temp_file_path = tmp_audio.name
try:
# Now we can safely use temp_file_path
segments, info = model.transcribe(temp_file_path, beam_size=5, language="en")
transcript = " ".join([segment.text for segment in segments])
print(f"Transcript: {transcript}")
return jsonify({"transcript": transcript})
except Exception as e:
print(f"Error: {e}")
return jsonify({"error": str(e)}), 500
finally:
# Cleanup
if temp_file_path and os.path.exists(temp_file_path):
os.remove(temp_file_path)
if __name__ == '__main__':
app.run(host='0.0.0.0', port=5000)

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services:
whisper-api:
image: python:3.9-slim
container_name: voice_whisper
restart: unless-stopped
working_dir: /app
volumes:
- ./app.py:/app/app.py
command: >
sh -c "pip install flask faster-whisper && python app.py"
ports:
- "5000:5000"
voice-bridge:
image: python:3.9-slim
container_name: voice_bridge
restart: unless-stopped
deploy:
resources:
limits:
memory: 500M
depends_on:
- whisper-api
working_dir: /app
volumes:
- ./mqtt_audio_bridge.py:/app/mqtt_audio_bridge.py
environment:
- XDG_CACHE_HOME=/root/.cache
command: >
sh -c "pip install paho-mqtt requests 'numpy<2' openwakeword tflite-runtime &&
python -c 'import openwakeword; openwakeword.utils.download_models()' &&
python mqtt_audio_bridge.py"

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import paho.mqtt.client as mqtt
import requests
import wave
import io
import numpy as np
import openwakeword
from openwakeword.model import Model
import collections
import threading
# --- CONFIG ---
# 1. VOICE SERVER (Audio IO)
VOICE_BROKER = "192.168.20.13"
VOICE_TOPIC_AUDIO = "voice/audio_stream"
VOICE_TOPIC_STATUS = "voice/status"
# 2. HOME ASSISTANT (Text Output)
HA_BROKER = "192.168.20.30"
HA_TOPIC_TEXT = "homeassistant/voice/text"
MQTT_USER = "MQTT_USER_REDACTED"
MQTT_PASS = "MQTT_PASS_REDACTED"
WHISPER_URL = "http://whisper-api:5000/transcribe"
WAKE_WORD = "hey_jarvis"
# --- STATE ---
BUFFER_SIZE = 1280 * 4
audio_buffer = collections.deque(maxlen=BUFFER_SIZE)
command_buffer = bytearray()
is_command_mode = False
print("Loading Models...")
owwModel = Model()
# --- HELPER FUNCTIONS ---
def transcribe_and_send(raw_data):
wav_io = io.BytesIO()
with wave.open(wav_io, "wb") as wav_file:
wav_file.setnchannels(1)
wav_file.setsampwidth(2)
wav_file.setframerate(16000)
wav_file.writeframes(raw_data)
wav_io.seek(0)
try:
files = {'audio': ('cmd.wav', wav_io, 'audio/wav')}
res = requests.post(WHISPER_URL, files=files)
if res.status_code == 200:
text = res.json().get("transcript", "").strip()
print(f"TEXT: {text}")
if text:
# PUBLISH TO HOME ASSISTANT BROKER
ha_client.publish(HA_TOPIC_TEXT, text)
# FEEDBACK TO ESP32 (Via Voice Broker)
voice_client.publish(VOICE_TOPIC_STATUS, "OK")
except Exception as e:
print(f"API Error: {e}")
# --- CALLBACKS ---
def on_voice_message(client, userdata, msg):
global is_command_mode, command_buffer
if msg.topic == VOICE_TOPIC_AUDIO:
payload = msg.payload
# 1. COMMAND MODE (Recording for Whisper)
if is_command_mode:
# Safety Check: Prevent Memory Overflow (cap at ~3MB)
if len(command_buffer) > 3000000:
print("Error: Buffer overflow. Resetting.")
is_command_mode = False
command_buffer = bytearray()
owwModel.reset()
return
# Append the audio chunk
command_buffer.extend(payload)
return
# 2. LISTENING MODE (Wake Word Detection)
# Convert bytes to numpy int16 for OpenWakeWord
audio_int16 = np.frombuffer(payload, dtype=np.int16)
# Feed the model
prediction = owwModel.predict(audio_int16)
if prediction[WAKE_WORD] > 0.5:
print(f"--- WAKE WORD DETECTED ---")
is_command_mode = True
command_buffer = bytearray()
client.publish(VOICE_TOPIC_STATUS, "WAKE")
elif msg.topic == "voice/status" and msg.payload.decode() == "processing":
# ESP32 stopped recording
if is_command_mode:
print("Processing...")
transcribe_and_send(command_buffer)
is_command_mode = False
command_buffer = bytearray()
owwModel.reset()
# --- MAIN ---
# Client 1: Voice Server (The Listener)
voice_client = mqtt.Client(client_id="Bridge_Voice")
voice_client.username_pw_set(MQTT_USER, MQTT_PASS)
voice_client.on_message = on_voice_message
voice_client.connect(VOICE_BROKER, 1883)
voice_client.subscribe([(VOICE_TOPIC_AUDIO, 0), ("voice/status", 0)])
# Client 2: Home Assistant (The Sender)
ha_client = mqtt.Client(client_id="Bridge_HA")
ha_client.username_pw_set(MQTT_USER, MQTT_PASS)
ha_client.connect(HA_BROKER, 1883)
print("Bridge Running (Dual Broker)...")
# Run loops in threads or blocking
# Since loop_forever blocks, we run HA loop in background and Voice loop in main
ha_thread = threading.Thread(target=ha_client.loop_forever)
ha_thread.daemon = True
ha_thread.start()
voice_client.loop_forever()