Advertise UID

Advertises a UID via the Eddystone protocol over Bluetooth.

bluetooth.advertiseUid(42, 1, 7, true);


This API is deprecated. The Eddystone beacon format is no longer supported, see Google Beacon format (Deprecated).


Bluetooth beacons are used to indicate proximity to a place or object of interest. Beacons use Bluetooth advertising to broadcast a small amount of data, which can be received and acted upon by anyone in range with a suitable device and software, typically a smartphone and application.

There are various beacon message formats, which define the way Bluetooth advertising packets are used as containers for beacon data. iBeacon is Apple’s beacon message format. Eddystone comes from Google.

Read more at .


  • namespace last 4 bytes of the namespace uid (6 to 9)
  • instance last 4 bytes of the instance (2 to 5)
  • power - a number representing the power level between 0 (short) and 7 (maximum range).
  • connectable - a boolean indicating whether or not the micro:bit should accept connections.


The bytes of namespace and instance are encoded to generate the 10 bytes UID namespace and 6 bytes UID instance.

UID namespace: [0, ..., namespace]
UID instance: [0, ..., instance]

See Also

stop-advertising, advertise-uid-buffer