Some VR cycling APP can't recognize and connect my control point characteristic.

[JohnCC]

Hi,

     We developing a fitness machine about cycle bike sensor. We create a FTM service include a control point characteristic and We use some VR app(Zwift/Rouvy) to test it. It look like working very well.

But now I tested other apps(RGT and Fulgaz). I found that they can connect to my FTM services but cannot recognize or connect to my control point characteristic. Why?

Here is my control point init code.

//Control point for FMS
    ble_add_char_params_t add_char_params;
    ftm_cp_char_format_t cp_char_init_data = {0};
    char init_value_encoded[64];
    
    cp_char_init_data.parameter_size = Max_Fitness_Machine_Control_Parameter_Size;

    // Add Fitness Machine Control Point characteristic
    memset(&add_char_params, 0, sizeof(add_char_params));
    add_char_params.uuid            = BLE_UUID_FITNESS_MACHINE_CONTROL_POINT_CHAR;
    add_char_params.max_len         = MAX_FTMS_LEN;
    add_char_params.init_len        = fitness_Machine_Control_encode(&cp_char_init_data, init_value_encoded);
    add_char_params.p_init_value    = init_value_encoded;
    add_char_params.is_var_len        = true;
    add_char_params.char_props.write = 1;
    add_char_params.char_props.indicate = 1;
    add_char_params.write_access      = p_ftms_init->control_point_wr_sec;
    add_char_params.cccd_write_access = p_ftms_init->control_point_cccd_wr_sec;

    err_code = characteristic_add(p_ftms->service_handle, 
                                  &add_char_params, 
                                  &p_ftms->control_point_handles);

Thank you.

[Kenneth]

Difficult to know, do you by any chance the possibilty to make an on-air sniffer log of working vs. failing?
https://www.nordicsemi.com/Products/Development-tools/nRF-Sniffer-for-Bluetooth-LE

Then I can at least look at whether there is somethin one app is trying to do that the other does not. If there is no difference to see I think it may be difficult to find out what the problem may be.

It could be possible to try the pts software from Bluetooth to verify your profile if you haven't already:
https://www.bluetooth.com/develop-with-bluetooth/qualification-listing/qualification-test-tools/profile-tuning-suite/ 

Kenneth

[JohnCC]

Hi Kenneth,

     

     I fixed this issue. I found that I don't advertising Fitness profile UUID during advertising period. I only advertising Cycling power profile. Like as below

ble_uuid_t m_adv_uuids[] = {BLE_UUID_CYCLING_POWER,  BLE_UUID_TYPE_BLE};

After I add some code like as below, some VR app can recognize and connect to me.

ble_uuid_t m_adv_uuids[] = {{BLE_UUID_CYCLING_POWER,  BLE_UUID_TYPE_BLE},
                               {BLE_UUID_FITNESS_MACHINE, BLE_UUID_TYPE_BLE}};

I think that some VR app will search our capability during advertising period.

Thank you. 

John