AirPlay Audio
Two Raspberry Pis run AirPlay receivers so any Apple device in the flat can stream audio to the kitchen or the bathroom without a dedicated speaker app.
Setup
| Location | Hardware | AirPlay version | Runs as |
|---|---|---|---|
| Kitchen | Raspberry Pi 3B | AirPlay 2 | Docker container (shairport-sync) |
| Bathroom | Raspberry Pi Zero W | AirPlay 1 | Native systemd service (older OS, legacy repo) |
The volume-boost problem
Both Pis' analog audio output is too quiet at full hardware volume, so
a software mixer stage (+20 dB via an ALSA softvol plugin) sits between
shairport-sync and the hardware. The hardware mixer itself is deliberately
left fixed at 100% / 0 dB, and shairport-sync only ever adjusts its own
internal software volume — this avoids the volume jumps and mixer
conflicts that show up when multiple layers all try to control loudness.
Bathroom-specific integration
The bathroom Pi also runs a small custom tool that starts an internet radio stream automatically when its light sensor detects the light has been switched on. A simple flag file signals whether AirPlay is currently active, so the automatic radio stream politely stays off while someone is actively AirPlaying — and resumes its normal behavior as soon as the AirPlay session ends.
Why this design
- Software-only volume control avoids ALSA mixer conflicts across two different loudness sources.
- The flag-file handoff is trivial to implement and doesn't need a message broker for something this simple.
- Docker on the kitchen Pi keeps that receiver easy to update; the bathroom Pi's older OS made a native install more reliable than fighting Docker on legacy hardware.