Devices

BLU devices and Bluetooth

BLU devices have no Wi-Fi. Without a gateway they'll never show up in the app.

Shelly BLU is the family of battery-powered Bluetooth devices: BLU Button1, BLU Door/Window, BLU Motion, BLU H&T and others.

They're cheap, they last for years on a coin cell, and they need no wiring. The price for that is that they have no Wi-Fi.

The gateway requirement

A BLU device can't talk to Shelly's cloud on its own. All it does is broadcast short Bluetooth messages. Something has to listen and pass them on.

That something is another Shelly device with Bluetooth — a Plus, Pro, Mini, Gen3 or Gen4 — acting as a gateway. Or a dedicated Shelly BLU Gateway Gen3.

In plain terms:

• If all you have is BLU devices and nothing else: they won't get into the app.
• The gateway has to be within Bluetooth range of the BLU device. Reckon on roughly 10–15 metres indoors, less through walls — that's metres, not rooms. A single wall in between can be enough to stop it working.
• The gateway has to be powered and online.

Gen1 devices can't be a gateway. They have no Bluetooth.

Enabling the gateway

The feature is off to begin with and is set per device, on the device that's going to be the gateway — not on the BLU device.

1. Open the Shelly that's going to be the gateway.
2. Go to the device's settings and from there to Bluetooth.
3. Turn on the Bluetooth gateway (Enable Bluetooth gateway).

Only then can the BLU device be found.

Firmware difference: older firmware also had a separate Enable Bluetooth switch that had to be turned on first. On newer firmware (2.0 and later) Bluetooth turns on automatically when the gateway function needs it, so that step may be absent.

Adding the BLU device

Once the gateway is running, the BLU device is added via Add device → Add via Bluetooth.

You need to have the phone close to the device. Many BLU devices need to be woken with a button press before they start broadcasting — a BLU Button1, for example, only broadcasts when someone presses it.

When the BLU device loses contact

BLU problems are almost always gateway problems. Work through these in order:

1. Is the gateway online? If it's offline, there's no way in for the BLU device.
2. Is the distance too great? Move the gateway closer, or add another one. Several devices can act as gateways at the same time.
3. Is the battery dead? BLU devices report battery level. A dying coin cell gives intermittent contact long before it runs out completely.
4. Was Bluetooth turned off on the gateway? A firmware update or a reset may have cleared the setting.

Delay is normal

BLU devices sleep to save battery. A door sensor reports immediately when the door opens, but a temperature sensor checks in at sparse intervals. The value not updating in real time isn't a fault — it's why the battery lasts for years.