Microphone Satellite

The thinnest HiveMind satellite. Runs microphone capture and Voice Activity Detection (VAD) on-device; everything else — wakeword detection, STT, intent handling, TTS synthesis — runs on the hub.

What runs locally: Microphone + VAD

What the hub provides: Wakeword, STT, intent processing, TTS (requires hivemind-audio-binary-protocol on the hub)

When to use it

• Devices with very limited CPU/RAM (Raspberry Pi Zero, recycled phones)
• Scenarios where you want zero local model downloads
• Personal homelab with a handful of devices on a fast LAN

When not to use it

mic-satellite streams every detected voice segment to the hub continuously (VAD-gated but not wakeword-gated). This is bandwidth-intensive and puts the full STT load on the server for all speech activity. It is appropriate for a small homelab. For a deployment serving multiple users, prefer voice-relay — local wakeword means audio only leaves the device after activation.

Install

pip install hivemind-mic-satellite

Requires Python ≥ 3.10.

Hub requirements

The hub must have hivemind-audio-binary-protocol installed and configured. Plain hivemind-core does not handle audio.

See Audio Binary Protocol.

Quickstart

1. On the hub — register a client:

hivemind-core add-client --name my-mic-sat
# note the access_key and password printed

2. On the satellite — write the identity file:

hivemind-client set-identity \
  --key <access_key> \
  --password <password> \
  --host <hub_host_or_ip>

3. Run:

hivemind-mic-sat

Or pass credentials directly without storing them:

hivemind-mic-sat --key <key> --password <password> --host <host> --port 5678

Configuration

mic-satellite reads the standard OVOS configuration at ~/.config/mycroft/mycroft.conf.

Plugin type	Config key	Notes
Microphone	listener.microphone.module	Required
VAD	listener.VAD.module	Required
PHAL	PHAL.ovos-phal-...	Optional, platform support

Example mycroft.conf excerpt:

{
  "listener": {
    "microphone": {
      "module": "ovos-microphone-plugin-alsa"
    },
    "VAD": {
      "module": "ovos-vad-plugin-silero"
    }
  }
}

How audio flows

[Microphone] → [VAD] → raw audio chunks → [HiveMind Hub]
                                              ↓
                                    [hivemind-audio-binary-protocol]
                                              ↓
                                    WakeWord → STT → IntentService
                                              ↓
                                    TTS synthesis → audio back to satellite
                                              ↓
                                    [Satellite plays TTS audio]

Audio is sent as BINARY messages with payload type RAW_AUDIO (type 1). The hub's AudioBinaryProtocol.handle_microphone_input() processes the stream.