Connect to BLE end get data fo services

Mihaill

Hi.
I have device with BLE (Bluetooth Low Energy). How I can connect to this device and get data from services?

jsulm

@Mihaill Start here https://doc.qt.io/qt-6/qtbluetooth-le-overview.html

Mihaill

@jsulm said in Connect to BLE end get data fo services:

@Mihaill Start here https://doc.qt.io/qt-6/qtbluetooth-le-overview.html

I can connected to device usin QLowEnergyService m_lowEnergyService, but cant create QLowEnergyService
It is not work

m_lowEnergyService = m_lowEnergyController->createServiceObject( QBluetoothUuid("{99999999-9999-c8c8-c8c8-d2d2d22d2d2d}"));

Whot me need do?

jsulm

@Mihaill said in Connect to BLE end get data fo services:

It is not work

What does this mean please? What happens? Did you also use https://doc.qt.io/qt-6/qlowenergycontroller.html#error to see whether any error occurred?
And according to the documentation: "The serviceUuid parameter must have been obtained via services()" (https://doc.qt.io/qt-6/qlowenergycontroller.html#createServiceObject). You seem to be passing uuid directly...

Mihaill

@jsulm said in Connect to BLE end get data fo services:

Did you also use https://doc.qt.io/qt-6/qlowenergycontroller.html#error to see whether any error occurred?

If I use this

m_lowEnergyService->error();

then my programm falling annd not run this code.
I get uuid serveci from QBluetoothDeviceInfo

jsulm

@Mihaill said in Connect to BLE end get data fo services:

then my programm falling annd not run this code.

Well, I guess because m_lowEnergyService is a null pointer.
But I wrote: https://doc.qt.io/qt-6/qlowenergycontroller.html#error (controller != service)...

Mihaill

@jsulm said in Connect to BLE end get data fo services:

Well, I guess because m_lowEnergyService is a null pointer.
But I wrote: https://doc.qt.io/qt-6/qlowenergycontroller.html#error (controller != service)...

Yes, m_lowEnergyService is a null pointer.Controller error: QLowEnergyController::NoError

JonB

@Mihaill
It is a null pointer because m_lowEnergyService = m_lowEnergyController->createServiceObject() failed! Retrieve the error from m_lowEnergyController to find out why.

jsulm

@Mihaill Did you also address this:
And according to the documentation: "The serviceUuid parameter must have been obtained via services()" (https://doc.qt.io/qt-6/qlowenergycontroller.html#createServiceObject). You seem to be passing uuid directly...

Mihaill

@jsulm said in Connect to BLE end get data fo services:

been obtained via services()
I get uuid form QBluetoothDeviceInfo

for(auto serviceUuid : device.serviceUuids()) {
                if (serviceUuid.toString() == "{99999999-9999-c8c8-c8c8-d2d2d22d2d2d}"){
                    m_bluetoothUuidService = serviceUuid;

and run this

m_lowEnergyService = m_lowEnergyController->createServiceObject(m_bluetoothUuidService);

but it's too not work

Mihaill

@JonB said in Connect to BLE end get data fo services:

Retrieve the error from m_lowEnergyController to find out why.

m_lowEnergyController not have error

JonB

@Mihaill
You asked why m_lowEnergyService->error() was causing a crash, when m_lowEnergyService had been returned as nullptr. To which I responded. You later changed the text of your question....

JonB

@Mihaill
Your latest code shows m_bluetoothUuidService being set if a certain serviceUuid is found. But we do not know whether it was found, and therefore whether m_bluetoothUuidService is set correspondingly. Why don't you put appropriate qDebug() statements into your code so you & we know for sure?

Mihaill

thanks. I use discoverServices and after fined my uuid I connected to service