If you are building your own Qt 5 then you should see if the notes about enabling the Win32 API apply to you.

Qt 5.14 adds a native Win32 port supporting Classic Bluetooth on Windows 7 or newer, and Bluetooth LE on Windows 8 or newer. It must be enabled at build time by configuration option -native-win32-bluetooth.

BT LE did have a restriction under the Win32 API that may also at play:

Note: The Received Signal Strength Indicator (RSSI), as well as the Manufacturer Specific Data advertised by Bluetooth LE devices are not supported by the Win32 backend. Also, it is only possible to find devices that have been previously paired through Windows Settings.

Qt 6.2 reintroduced Qt Bluetooth after it was ported from Qt 5. In that process, "Win32 backend was removed. As consequence there is no more QtBluetooth with MinGW." This may have changed the default BT API used and explain a changed behaviour. Cannot say for sure without reading the actual code.

@JonB Oh, I thought I had the same, fixed it, thanks

@sierdzio Thank you very much!

Hi @TUStudi,

This virtual maschine need to support Bluetooth Low Energy.

If you have an USB bluetooth dongle/adapter, than you can most likely inject this dongle into the virtual machine and use it there. Note that even bluetooth adapters built into your laptop may be an USB devices and could work that way.

So I'd say it depends on a test.

Regards

Ah ok sorry! Indeed last time I worked with BT it was with older Qt version.

The QTBluetooth Central API is not supported on any platform.
see the first table in Qt Bluetooth

i had same error in my project.
this page helped me -> https://forum.qt.io/topic/117241/why-qlowenergyservice-unknownerror/2

i have changed my code from

connect(controller, &QLowEnergyController::discoveryFinished, this, &Device::serviceScanDone);

to

connect(controller, &QLowEnergyController::discoveryFinished, this, &Device::serviceScanDone,Qt::QueuedConnection);

and problem disappeared.

@J-Hilk Thank you, JonB and you were right. For me it actually makes more sense that e.g. at first you connect to the device and then you say "okay, if the signal "connected" is emitted then call the function x.y.". So after changing it, it works now. However, after getting all services and calling "service->discoverDetails" and then "service->characteristics" the characteristics List is empty.

After connection is successfull:

void Scanner::startServiceDiscovery(){ connect(controller, &QLowEnergyController::discoveryFinished, this, &Scanner::discoveryFinished); controller->discoverServices(); } void Scanner::discoveryFinished(){ qDebug() << "\nService Discovery finished. Following Services found:\n"; QList<QBluetoothUuid> serviceList = controller->services(); for(QBluetoothUuid &sl : serviceList){ qDebug() << controller->createServiceObject(sl)->serviceName() << "Uuid: " << sl; } uartService = controller->createServiceObject(adafruitServiceUuid); qDebug() <<"\nChose the following service: " << (*uartService).serviceName(); connect(uartService, &QLowEnergyService::stateChanged, this, &Scanner::printChars); qDebug() << uartService->state(); //here the state is QLowEnergyService::DiscoveryRequired uartService->discoverDetails(); } void Scanner::printChars(){ qDebug() << uartService->state(); // here the state is now QLowEnergyService::DiscoveringServices const QList<QLowEnergyCharacteristic> chars = uartService->characteristics(); qDebug()<< chars.size(); //however the list size is 0 for (const QLowEnergyCharacteristic &ch : chars) { qDebug() << &ch; } }

btw: I know that there is an example for BLE Scanner. But for a project, I want to create an own desktop application which connnects to a peripheral and live plots the data which are received from the sensor with qcustomplot. So I need a QWidget Application because QCustomPlot is a widget...

@efiLabs I am facing same kind of problem. I working on my linux laptop (ubuntu 18.0). I have run an application in cetral mode of ble. When this application is started to receive the data it receive some 20 packets of 509 bytes chunks and then after it hangs. When i googled it, i realized it may be the problem of throughput.

Is there any api in Qt to tell the peripheral device to send the data in low throughput ?

@Ashi Sorry, I'm too late to answer this post. I think you should try with msvc compiler, not mingw

@helenebro I managed to get to the bottom of the problem (it is due to a firmware bug in these BLE low-cost modules), see my bug report under https://bugreports.qt.io/browse/QTBUG-83363.