Deployment

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systemd service

Create /etc/systemd/system/hivemind-mic-sat.service:

[Unit]
Description=HiveMind Microphone Satellite
After=network-online.target sound.target
Wants=network-online.target

[Service]
Type=simple
User=pi
ExecStart=/home/pi/.local/bin/hivemind-mic-sat
Restart=on-failure
RestartSec=10
Environment=PYTHONUNBUFFERED=1

[Install]
WantedBy=multi-user.target

Adjust User and the ExecStart path to match your system. Find the installed binary:

which hivemind-mic-sat

Enable and start:

sudo systemctl daemon-reload
sudo systemctl enable hivemind-mic-sat
sudo systemctl start hivemind-mic-sat

View logs:

journalctl -u hivemind-mic-sat -f

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Passing credentials to the service

Option 1: identity file (recommended): run hivemind-client set-identity ... as the service user before you start the service. The satellite reads the file automatically.

Option 2: environment variables in the unit:

[Service]
Environment=HM_KEY=abc123
Environment=HM_PASSWORD=secret
Environment=HM_HOST=192.168.1.10
ExecStart=/home/pi/.local/bin/hivemind-mic-sat --key ${HM_KEY} --password ${HM_PASSWORD} --host ${HM_HOST}

Or use EnvironmentFile=/etc/hivemind-mic-sat.env to keep secrets out of the unit file.

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Raspberry Pi Zero notes

The Raspberry Pi Zero, and the Zero 2 W, are the target hardware for this satellite.

Recommended OS

Raspberry Pi OS Lite (64-bit for Zero 2 W; 32-bit for Zero W). Install Python 3.10 or later through the official packages or the deadsnakes PPA.

Audio hardware

The Pi Zero has no built-in audio output. Common options:

Option	Notes
USB audio dongle	Cheapest; plug-and-play
I2S DAC HAT (for example pHAT DAC, IQaudio)	Better quality; requires a device tree overlay
USB microphone + speaker combo	Single device, simplest wiring
ReSpeaker 2-mic HAT	Microphone array, built-in speaker output

Identify ALSA devices after you connect hardware:

arecord -l   # input devices
aplay -l     # output devices

Set the correct device index in mycroft.conf (see configuration.md).

ALSA default device

If the USB audio device is not the default, either configure it in mycroft.conf or create /etc/asound.conf:

defaults.pcm.card 1
defaults.ctl.card 1

Replace 1 with the card number from arecord -l.

Performance tips

• Use ovos-vad-plugin-webrtcvad instead of Silero on a Zero W to use less CPU.
• Disable unnecessary services on the Pi to free RAM.
• Avoid running a desktop environment on the satellite.
• The satellite uses roughly 40-80 MB RAM under typical load (mic + VAD + WebSocket client).

Network

Wi-Fi works on the Pi Zero W and Zero 2 W. For latency-sensitive deployments, a USB-to-Ethernet adapter is more reliable.

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Autostart without systemd (user session)

Add to ~/.bashrc or ~/.profile for single-user systems:

hivemind-mic-sat &

Or use a cron @reboot entry:

crontab -e
# add:
@reboot /home/pi/.local/bin/hivemind-mic-sat >> /home/pi/mic-sat.log 2>&1

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Docker

A minimal Dockerfile:

FROM python:3.11-slim

RUN apt-get update && apt-get install -y alsa-utils libportaudio2 && rm -rf /var/lib/apt/lists/*

RUN pip install hivemind-mic-satellite ovos-microphone-plugin-alsa ovos-vad-plugin-silero

COPY mycroft.conf /root/.config/mycroft/mycroft.conf

CMD ["hivemind-mic-sat", "--host", "host.docker.internal"]

Note: audio access inside Docker requires ALSA device passthrough (--device /dev/snd).

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