Peripheral connect with Windows BLE

[martial123]

Hi everyone,

I have make a little application to connect my computer (laptop Windows with intern BLE) with a peripheral device in BLE.

I am able to detect this device.
After that, I create a central role and pass as arguments my device peripheral detected.
And after that i launch connection with :

void QLowEnergyController::connectToDevice()

and i wait my connect active :

&QLowEnergyController::connected

but in fact, nothing is happening.
If I look on my icon BLE on windows 10 (manage notification tab) I see my BLE icon switch between connected(1) / not connected...

So I understand there is something wrong.
My peripheral device need code (password 123456) to pair before connect on it service.
I thinks this is the problem .. but on Qt ,
I did not see any connection function where you could pass the password.

Is there such a function?

Thanks.
Martial

[martial123]

Any idea team ??

[J.Hilk]

@martial123 Is the password required before or after the service discover ?

If it's after the discovery, you could potentially the writeDescriptor function to transfer data. I use it to subscribe to the service.

Is this what you mean?

[martial123]

@J-Hilk
Hi ! , unfortunatly, this is before discover services, here my code to better understand ( inspire from example of Qt heart game ):

    m_deviceDiscoveryAgent = new QBluetoothDeviceDiscoveryAgent(this);
    connect(m_deviceDiscoveryAgent, &QBluetoothDeviceDiscoveryAgent::deviceDiscovered, this, &MainWindow::addDevice);

void MainWindow::on_m_scanBLEButton_clicked()
{
    qDebug()<< " we are in scan ble button "<<endl;
    //m_deviceDiscoveryAgent->setLowEnergyDiscoveryTimeout(5000);
    m_deviceDiscoveryAgent->start(QBluetoothDeviceDiscoveryAgent::LowEnergyMethod);
}
// I push on scan button, this slot start(just above) and the connect are true when agent discover low energy device. when we have this, we jump in slot addDevice:

void MainWindow::addDevice(const QBluetoothDeviceInfo &device)
{
    // If device is LowEnergy-device, add it to the list
    if (device.coreConfigurations() & QBluetoothDeviceInfo::LowEnergyCoreConfiguration)
    {
        if(device.name() == "CERTIF") // I filter because i just want to add my device named CERTIF.
        {
            ui->m_deviceAvailableTextBox->append(device.name());
            ui->m_deviceAvailableTextBox->append(device.address().toString()); //append my device CERTIF and his mac address
            m_control = QLowEnergyController::createCentral(device, this); //here I creat a central (my pc ) with this device (CERTIF)
            m_control->setRemoteAddressType(QLowEnergyController::RandomAddress);
            //or
            //m_control->setRemoteAddressType(QLowEnergyController::PublicAddress);
        }
    }
}

//so after that, I see on my TextBox (m_deviceAvailableTextBox) CERTIF and his adress.
//Now I click on an other Pushbutton : 

void MainWindow::on_m_connectBLEButton_clicked()
{
    qDebug()<< " we are in connect ble button "<<endl;
    m_control->connectToDevice(); //main point were FAILLED.
}
// slot in case or we are connect or error appears: 

    connect(m_control, QOverload<QLowEnergyController::Error>::of(&QLowEnergyController::error),[this](QLowEnergyController::Error error)
    {
        qDebug()<< "cannot be connect to the controller "<<error<<endl;
        ui->m_deviceAvailableTextBox->append("cannot be connect to the controller...");
    });

    connect(m_control, &QLowEnergyController::connected,[this]()
    {
        qDebug()<< "we are in connect controller "<<endl;
        ui->m_deviceAvailableTextBox->append("Controller connected. Search services...");
        //m_control->discoverServices();
    });

the point is, none of the slots are triggered, connected no and Error no, I have just my app runing ,and if i check my tab on my laptop On bluetooth icon I see my BLE icon switch between connected(1) / not connect.

What i know, with nRF connect software and dongle nRF, I am able to connect with my device CERTIF because after scan, i try to pair (connect) with this and nRF software open window were i can write down my password (123456) and just after that, I am connected and i can connect to a service ..

In Qt I am bloqued just before ..
I hope this is more clear..

Thanks

[J.Hilk]

@martial123
well, this seems more like an BLE issue than Qt.

The windows api is still, meh
can you pair/connect to it from the windows settings directly ? before trying it with qt?

[martial123]

@J-Hilk
Good Question, I have try, but not succeed . i click on add device bluetooth, i detect him, i click on him and i receive this just below CERTIF : try connecting your device again .
I have check on my device manager and my laptop have puce with BLE :

Edit:
I will try to remove this password in my firmware device, for check if error come from here . but your right, propably it is Window error and not Qt. But still, this is strange that not have any function to pass password to connect ...

if I managed to connect with my dongle, the problem would be quickly resolved.. see my other topic:
https://forum.qt.io/topic/113213/nrf-connect-dongle-with-qt-for-windows

[martial123]

ooh, and I have this log in my Qt app after long time to connect :

qt.bluetooth.winrt: Could not await services operation