Microstream

Bidirectional audio streaming between Particle microcontrollers and Node.js servers. Build voice assistants, intercoms, and audio IoT devices with real-time push-to-talk communication.

Overview

Microstream provides two components that work together:

Component	Package	Installation
Server	microstream-server	npm install microstream-server
Firmware	microstream	particle library add microstream

flowchart TB
    subgraph Server["☁️ Node.js Server"]
        direction LR
        S1["Transcribe"] --> S2["Process"] --> S3["Synthesize"]
    end

    subgraph Device["Particle MCU (Photon/Argon)"]
        direction LR
        Mic["🎤 Microphone"]
        Speaker["🔊 Speaker"]
    end


    Mic -- "PCM @ 16kHz" --> S1
    S3 -- "PCM Response" --> Speaker

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Quick Start

1. Server Setup

npm install microstream-server

const { MicrostreamServer } = require('microstream-server')

const server = new MicrostreamServer({ port: 5000 })

server.on('session', (session) => {
  console.log(`Device connected: ${session.id}`)

  session.on('audioEnd', (wavBuffer) => {
    // Process audio (speech-to-text, AI response, etc.)
    // Then send audio back to device:
    session.play(responseAudioBuffer)
  })
})

server.listen(() => console.log('Listening on port 5000'))

2. Firmware Setup

particle library add microstream

#include "Microstream.h"

#define MIC_PIN      A0
#define SPEAKER_PIN  A3
#define BUTTON_PIN   D3

Microstream stream;
bool buttonDown = false;

void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  MicrostreamConfig cfg;
  cfg.sampleRate = 16000;
  cfg.bitDepth = 16;
  cfg.micPin = MIC_PIN;
  cfg.speakerPin = SPEAKER_PIN;

  stream.begin("YOUR_SERVER_IP", 5000, "/", cfg);
}

void loop() {
  stream.update();

  bool pressed = (digitalRead(BUTTON_PIN) == LOW);

  if (pressed && !buttonDown && stream.isConnected()) {
    buttonDown = true;
    stream.startRecording();
  }

  if (!pressed && buttonDown) {
    buttonDown = false;
    stream.stopRecording();
  }
}

3. Hardware

Component	Connection	Notes
Electret mic + MAX4466 amp	A0	Any analog pin
Speaker + amp	A3 (Photon) or A6 (Argon)	DAC output
Push button	D3	Optional, active low

Documentation

• Server API Reference - Full Node.js API, events, protocol details
• Firmware API Reference - Particle library API, hardware wiring, callbacks

Examples

Example	Description
Basic Firmware	Minimal push-to-talk
Chatbot Firmware	Voice assistant with LED feedback
Voice Assistant Server	OpenAI Whisper + GPT + TTS integration
Echo Server	Loopback testing

Features

Server

• TCP and WebSocket on same port (auto-detected)
• Automatic PCM → WAV conversion
• Multiple concurrent device sessions
• Event-driven API

Firmware

• Interrupt-driven audio capture
• Ring-buffered playback
• Automatic reconnection with backoff
• Playback level callbacks for visualizations

License

MIT License - see LICENSE