Control a Bluetooth Marpac Dohm sound machine from Home Assistant as a media player (on/off + volume). The BLE protocol was reverse-engineered from the official app; see docs/protocol.md and the docs/reverse-engineering.md runbook.

Upgrading from 0.1.x? The Dohm used to be a fan entity. It is now a media_player, because what you adjust on a sound machine is loudness, not airflow — and volume is something the rest of Home Assistant already understands. This changes the entity ID, so any automation, script, or dashboard card referring to fan.<your dohm> needs to point at media_player.<your dohm> instead. The old fan.* entity is left behind in the registry as unavailable — delete it yourself from Settings → Devices & Services → Entities.

1. In HACS, add this repository as a custom repository (category: Integration).
2. Install Marpac Dohm and restart Home Assistant.
3. The Dohm should be auto-discovered. If not, go to Settings → Devices & Services → Add Integration → Marpac Dohm.
4. Hold the top button on the Dohm for ~5 seconds to make it discoverable, then select it. After this one-time pairing, Home Assistant reconnects on its own.

One controller at a time. The Dohm stores exactly one pairing, and the top button grants a new one, replacing whatever was there. That button is only for pairing — it plays no part in normal operation, so pressing it while troubleshooting will break a working setup. If the phone app has the pairing, forget the Dohm there before adding it here.

• It connects but never responds. The Dohm only replies over a paired (encrypted) link, so this means the stored pairing no longer matches. Hold the top button ~5 seconds; the integration clears the stale pairing and re-pairs on its own within about a minute, and raises a repair notification if it can't.
• Adding it does nothing / says it's already configured. An existing config entry is blocking the add, and disabled entries are hidden by default. Turn on show disabled entries under Settings → Devices & Services, then delete the old one before re-adding.
• It went unavailable and stayed there. Check the logs for custom_components.dohm; the version history and diagnostic recipes are in docs/debugging.md.

• A media player entity (device class speaker): turn on/off and set volume across the device's 10 levels. Volume up/down step exactly one level rather than the usual 10%, so every press is a setting the device actually has, and the control snaps immediately to the level the Dohm took — drop the slider at 43% and it moves to 50% right away rather than after a round-trip.
• Voice control via the standard volume intents — "set the white noise to 40 percent", "turn the white noise down" — which a fan entity can't answer.
• A proper device entry (manufacturer Marpac, model Dohm), with firmware/ serial pulled from the device when available.

The Dohm has no silent setting, so volume 0 is the quietest level rather than off; use turn off for silence. It plays no media, so no transport controls, sources, or metadata are exposed and it is never offered as a playback target.

Scheduling is intentionally left to Home Assistant automations rather than the device's onboard timer — far more flexible, and it sidesteps the device's drifting onboard clock.

• A Bluetooth adapter on the Home Assistant host or an ESPHome Bluetooth Proxy within range of the Dohm. No external Python packages — the integration is self-contained and uses Home Assistant's bundled Bluetooth stack.

The reverse-engineering engine (protocol.py, client.py) is vendored inside custom_components/dohm/ and unit-tested without hardware:

uv run pytest

tools/ holds the BLE exploration helpers used to map the protocol (probe.py, explore.py, extract_writes.py).

MIT.