Important: Please read the Qt Code of Conduct -

Sometimes connection times out when trying connecting QT BLE central applic with BLE peripheral applic if no long term key is loaded at central side

  • Hi,

    I have made a simple BLE setup between two embedded boards both with BLE connectivity.


    On the Beagle Bone Black with LINUX OS I run a simplified QT BLE central application that connects with a heart rate peripheral application running on a nRF52 DK board with ZEPHYR RTOS.

    The BLE connection between both applications is only successfully when on the Linux board I load in first the Long Term Keys (via the btmgmt tool and the ltks command) before setting up the BLE connection with the HR peripheral application running on the nRF52 board.

    Is there a way this authentication process and exchange of keys (loading in the long term key) can be done in QT when setting up the BLE connection and I don't have to rely on the btmgmt tool for loading in the LTKs?

    Using QT 5.11.3 on (Yocto distribution) Linux (4.14) for BBB.
    Bluez v5.50


    Best regards,

    UPDATE 16/01/2019

    UPDATE 12/01/2019

    It seems in some way Linux kernel related.
    With the Linux kernel V4.14 I have to load in the long term keys.
    With the Linux kernel V4.20 I no longer have to do this.

    UPDATE 12/01/2019

    Not sure why but sometimes it works without having to load in the long term keys... .
    Today I restarted all, peripheral and central, and I no longer have to run btmgmt for loading in the long term keys... (ltks).
    Makes it very strange all...

Log in to reply