Secondary Bluetooth Low Energy (BLE) allows a device to be located if it loses power (due to critically low battery) or is powered off. The location of the device is detected by the seeking device that listens for signals transmitted from the secondary BLE beacon of the powered off device. Attempts to locate the lost device must occur soon after the device loses power, prior to loss of power from the secondary BLE radio.
There are 2 types of secondary BLE:
- Device-based - The secondary BLE radio is located on the device. In addition to the Device Tracker license, a separate BLE license is required for the secondary BLE to operate. Although the Device Tracker license is monitored by the web portal, this does not apply to the BLE license.
- Battery-based - The secondary BLE radio is located on the battery. When purchasing the BLE battery, it comes with a 3-year term Device Tracker license for full operation of Device Tracker. A BLE license is not required.
Secondary BLE is used to find a device that is powered off. This should not be confused with the built-in device primary BLE, used for finding devices that are powered on.
Secondary BLE must be enabled during setup to be able to locate the device when it has no power. Configuration differs slightly depending on the location of the secondary BLE radio:
- Device-based - The secondary BLE radio is located on the device. To enable the secondary BLE beacon, see Secondary BLE Configuration.
- Battery-based - The secondary BLE radio is located on the battery. There is a difference in behavior when using battery-based secondary BLE, see battery-based BLE behavior. To enable the secondary BLE beacon, see Secondary BLE Configuration and ensure the Reference RSSI value is set as specified.
There are behavioral differences between device-based and battery-based secondary BLE. See battery-based BLE behavior. When locating a device based on its secondary BLE beacon, the Play Sound feature is disabled during device search since it cannot function due to the loss of device power. The Secondary BLE state is viewed from the Device Details screen. See Secondary BLE for reference.