Device Discovery

Devices are added automatically to Home Assistant the first time they send a message. You may need to trigger doorbells and motion sensors manually to register them. New devices trigger a notification inside Home Assistant. Note that weak signals may show up as unexpected devices or as devices with missing fields.

Post-Connection Registration

Only devices heard after the integration connects are automatically registered. On connect, the rtl_433 server replays its recent backlog. The integration uses frame timestamps to seed runtime state from that backlog without flooding the device registry with devices that transmitted before Home Assistant connected.

A previously unknown device is added the first time it transmits after the connection. This assumes the rtl_433 server and Home Assistant clocks are roughly in sync.

Discovery Toggle

Each hub has its own discovery toggle. Turning discovery off stops new devices on that hub from being added. Devices that already exist keep updating. Turning it back on lets new and previously deleted devices appear again when they transmit.

Deleting Devices

To remove an unwanted device, open it under Settings → Devices & Services → rtl_433 → the device → Delete.

If unwanted devices keep registering, disable device discovery in the hub settings. This is highly recommended in urban areas!

Replacing a Device That Changed Id

Many battery-powered sensors pick a new random transmitter id every time their batteries are changed. rtl_433 identifies a device by that id, so the sensor comes back as a brand-new device with new entities and no history, while the original stops updating and eventually goes unavailable.

To move the original device onto its new id, open Settings → Devices & Services → rtl_433 → Configure → Replace device. Pick the Device to keep — the existing device whose history you want to preserve — then pick the New device, the one that appeared after the batteries were changed. Devices of the same model are listed first, since a battery swap does not change the model.

The device you keep takes over the new id, and the duplicate device and its entities are removed. The kept device's entity ids do not change, so its history, statistics, dashboards and automations carry straight through, and its calibration, availability timeout override, motion clear delay and event types come with it. Any field the replacement has already reported is added to the device's known fields. The short history the duplicate recorded before the replace is discarded along with it.

Because those entity ids are kept exactly as they were, they still spell out the old id — an entity named sensor.acurite_986_1a2b_temperature keeps that name after being re-pointed at id 9f3c. That is what preserves the history, so it is worth leaving alone. You can rename the entity if the stale id bothers you, but renaming it starts a new history under the new entity id.

This works with device discovery turned off, which is recommended above for urban areas. The replacement only has to have been heard by the receiver at least once — it does not need to have been registered as a device. If the replacement is not in the list yet, wait until it transmits again and reopen the step.

To confirm you are picking the right device, check the Serial number on the device info card: it is the id rtl_433 decoded for that device, plus its channel and subtype when it has them. Unlike the device name, the serial number is not affected by renaming the device, so it always shows the transmitter the device is currently tracking — the old id before a replace, the new one after.