Sensolus trackers Bluetooth visibility

Learn the general principle of using a magnet to make a tracker visible and connectable to mobile app via Bluetooth Low Energy (BLE).

Updating firmware on the tracker or extracting debug logs out of the tracker can be done over the Bluetooth connection between your mobile phone and the tracker. Before you can do this, it is important to make your tracker connectable over Bluetooth. How to do this is explained here.

Quick steps to make trackers Bluetooth connectable using mobile app

As part of certain technical tasks, the mobile app needs to connect to a tracker using Bluetooth communication. To conserve energy, by default the trackers deactivate this Bluetooth channel unless activated by a magnet. Follow these instructions:

  1. You will need the following:
    • Have a small magnet at hand.
    • You must be in close proximity to the tracker (ideally less then 5m). Otherwise, the Bluetooth connection might be unstable or too slow.
    • You have a smartphone with the Sensolus mobile app installed (Mobile app installation and login).
  2. Briefly hold the magnet on the tracker (1 second is enough). You should see a green LED light as sign of confirmation.
  3. The tracker is now visible via Bluetooth to the mobile app during 60 seconds (by default).
  4. Continue the steps in the mobile app.
Note: Note that holding the magnet longer than 5 seconds over an unactivated tracker will cause it to be activated. If the tracker was already activated, the tracker will connect to the cloud platform and check if a new configuration is available. This is also described in the short installation manual for each tracker model.

How it works

For local communication to the tracker, the mobile app uses a Bluetooth connection (more specifically: Bluetooth Low Energy - BLE). To initiate a connection, the tracker must first advertise itself over the BLE. Too conserve battery life, most trackers will only start BLE advertising when the magnet activation procedure is performed. A magnet activation will cause BLE advertising during 60 seconds by default, after which the advertising is switched off again.

In some specific use cases, the tracker BLE advertising may be switched on permanently (to make trackers permanently visible to other BLE scanning devices). It is still needed to use the magnet to make the tracker connectable (unless the trackers are configured to be always connectable).

Note: Do not confuse this BLE advertising activation of tracker with the BLE sensor measurement interval. This is handled differently, by the trackers firmware logic.