@SpaceToon said in Unknown Exception is not beeing caught in trycatch-Block (Bluetooth Low Energy, ServiceDetailsDiscovery): @KH-219Design : Thank you very much for your suggestion, for using the lowenergy example from Qt. I did this and the same error occurs there! For this reason, I copied the following code from there and paste it in my .cpp file @SpaceToon I'm truly happy to hear you are able to make forward progress on this! This year marks the first year that I have ventured into BLE using Qt, and I have hit some minor hiccups myself. That is why your post caught my attention in the first place. However, I am working on Android and you are on Windows, which have very different backend/underlying BLE system stacks. So based on the difference in operating systems, I was doubtful if anything I learned would really translate directly here. Your watershed moment about QLowEnergyController::Error prompted me to go look at my code again to see what I am doing in case of QLowEnergyController::Error. I noticed that in my slot I have this comment: // The Qt API for QLowEnergyController has some confusing // overlap/ambiguity. When we get "ConnectionError" I would EXPECT that // the signal QLowEnergyController::disconnected would also be // forthcoming. But it seems (by observation) that this is not how it // works. So we have to treat BOTH the disconnected signal and the // error signal as signs of a disconnection. ... so maybe you and I did actually run into a very similar pitfall after all! It would be great to know if there is some null-reference bug in Qt BLE itself, but neither you nor I may have time to investigate that further. Since we both seem to have worked around our respective pain points, may we carry on and each deliver a successful project! You also asked: Did you compile Qt for debug, and can the debugger see/know the location of the corresponding Qt source files? Which is a very useful tactic, which I have done many times on Linux Qt. I just read some of this: https://stackoverflow.com/questions/5571098/how-can-i-make-msvc-debugger-step-into-qt-library-source-code-again/5576414 Which refers to compiling the QtCored5.dll DLL(s) for oneself. (This is essentially analogous to how I do it on Linux, but building Qt from source is usually several hours of effort on the first time... and I'm not talking about the additional potential hours of just letting the compiler run!) Maybe someone else in this thread has had personal experience with debugging into Qt source files on Microsoft Windows. Or maybe that could be a new thread!

See https://bugreports.qt.io/browse/QTBUG-86095 for further informations

I have exactly the same problem see my topic. Actually I did not find any solution

@mrjj said in Writing to the file continuously in Qt (realtime data)?: @SpaceToon hi Yes you just want to open it once. But i dont see you calling flush anywhere ? Oh, I forgot to paste the flush here, it is actually in my code directly after the write-statement. Thank you very much :)

Okay, I have solved the problem with a workaround: In the code for my development board I added a new line character after every value. Then, in my Qt code I check every time the SLOT is called if the value does have a new line char. Either the value is saved in another variable until it receives a value with a new line character or it is output immediately (if it has a new line character). static QString newValue= ""; void MainWindow::updateData(const QLowEnergyCharacteristic &c,const QByteArray &value) { newValue = newValue + (QString)value; if (newValue.contains("\n") || newValue.contains("\r")){ ui->dataList->addItem(newValue.simplified()); ui->dataList->scrollToBottom(); newValue = ""; } }

Thank you both very much.

Thank you for your reply. I found this in the documentation: In some cases the peripheral generates value updates which the central is interested in receiving. In order for a characteristic to support such notifications it must have the QLowEnergyCharacteristic::Notify or QLowEnergyCharacteristic::Indicate property and a descriptor of type QBluetoothUuid::ClientCharacteristicConfiguration. Provided those conditions are fulfilled notifications can be enabled as shown in the following code segment: QLowEnergyCharacteristic batteryLevel = service->characteristic( QBluetoothUuid::BatteryLevel); if (!batteryLevel.isValid()) return; QLowEnergyDescriptor notification = batteryLevel.descriptor( QBluetoothUuid::ClientCharacteristicConfiguration); if (!notification.isValid()) return; // establish hook into notifications connect(service, SIGNAL(characteristicChanged(QLowEnergyCharacteristic,QByteArray)), this, SLOT(characteristicChanged(QLowEnergyCharacteristic,QByteArray))); // enable notification service->writeDescriptor(notification, QByteArray::fromHex("0100")); So you were right. But what I do not understand: The writeDescriptor function "Writes newValue as value for descriptor." But what "value" is the QByteArray::fromHex("0100") ? Because when i write the same code for my application and when I call value() on the ClientCharacteristicConfiguration Descriptor from my RX characteristic the output is \x00\x00

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

@TUStudi AFAIK writing an MS Excel file is not possible with Qt directly. You need some additional stuff. But writing to a file in general (raw textfile, JSON, XML... etc) is quite easy.

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.

@martial123 These dongles are needed, if you use the node.js Bluetooth Low Energy library called "noble" (this video is actually about how to use noble), I only linked it because he also explains how to use Zadig. I don't know if your Dongle, that you have know, will work with Qt BluetoothLE library, just try it, if not, you could then try one of these listed in the video .

Thank you very much for your reply. @sierdzio said in Bluetooth LE performance in different platforms: Is the simulated beacon paired in Windows Bluetooth settings? Without it, Qt will not detect it! (this will be fixed in Qt 5.14 I think)., Unfortunately, Windows does not allow me to pair the simulated iBeacon since it does not appear in the available Bluetooth devices list from the control panel. @sierdzio said in Bluetooth LE performance in different platforms: Also, make sure you're using the newest Windows version with all updates. Unfortunately, Bluetooth support on Windows is quite bad, has memory leaks etc. In early Windows 10 builds it was barely working at all. Sure, it is the latest Windows version with all updates. I was also trying to compile the Qt 5.15 source available in the repo to enable the win32 Bluetooth API to see if it makes any difference but I wasn't able to compile it... But this was just a curiosity. For me it's OK to consider Windows as the least compatible platform for the moment. About Android, I was able to tune the application and now it can properly detect the simulated iBeacon. I was using the Bluetooth LE scanner example but I hadn't checked the manifest file so that was probably the issue.

@SpaceToon said in Dummy backend running. Qt Bluetooth module is non-functional (Bluetooth Low Energy): So is it possible with the MSVC Compiler? No. You will need to build your code for Linux. It is better to do this on a Linux machine as cross compiling from Windows to Linux will be a lot of work. You can have a virtual machine with Linux to build for Linux.

I tested it with Qt 5.11.0, but more deficiency detected. The General Attribute also undetected and characteristic write is not working :(

@NicoFrom13 Hi, Were you able to use this work in progress qtconnectivity? Is it properly working ?

Awesome man. That show me that sometimes ask the question is more usefull than searching for hours.... I didn't know that i could not use Windows SDK with MinGW i understand now. windows SDK needs to be with Visual compiler ... Many thanks have a nice Day.

Hi and welcome to devnet, Glad you found out and thanks for sharing. Since you have ti working now please mark the thread as solved using the "Topic Tools" button so that other forum uses may know a solution has been found :)

Then I'd recommend asking this on the interest mailing list. You'll find there the QtBluetooth module maintainers/developers.

Hi, There might just be not much people on this forum that use the QtBluetooth module. In that case, there's always the interest mailing list where you can find Qt's developers/maintainers.

a little bit late but for anybody searching. Indication is different than notification in that there is a confirmation that data sent from peripherical (hardware measuring device as heart rate) to the central device (same as your phone app) reached. Notification does not offer this confirmation. It is something like udp (no confiramtion available) and http (confirmation available)

I know this question is old, but it seems noone is answering BLE related questions here. (I've just posted such a question myself, and fear noone will anwer it either). I developed an app based on the same example, and it worked fine under both android 4.3.2, 5.1.2, and 6.0. However, the customer came with an android 5.01, and sure enough, the app did not work as expected. It seemed to "hang" and tried to connect to two devices at the same time, etc. We did not investigate it further. This was with Qt 5.6, so the issue is not resolved, and may never be, since with newer versions of Android it is working fine.

Hi, There's a WIP branch in the qtbluetooth module for Windows, you can check the state there.

@kuzulis Thanks!

@pbljung said in BLE demos fail on Android: errorReceived these errors can happen see my comments on top of void MyBluetoothDeviceInfo::onControllerError(QLowEnergyController::Error error) in https://github.com/ekke/ekkesBTLEexample/blob/master/cpp/bt/mybluetoothdeviceinfo.cpp not only 133 (reported as unhandled error) also 34 and 8 can happen see also all the discussions at https://bugreports.qt.io/browse/QTBUG-31674 per ex from my comment on 133: while developing new example app for BT LE and Qt 5.8 using QtQuickControls2 for Android, iOS I also run into GATT ERROR 133 googled and found out that this bug iseems not to be a Qt Bug. some more infos here: https://github.com/NordicSemiconductor/Android-nRF-Toolbox/issues/9 https://android.googlesource.com/platform/external/bluetooth/bluedroid/+/android-5.1.1_r13/stack/include/gatt_api.h of course would be great if Qt could handle error 133 my workaround: if getting a QLowEnergyController::ConnectionError I try to reconnect up to 5 times with a delay of 1000ms In most cases 2nd or 3rd retry will connect without the error. BTW: find out more on my new BTLE Example APP: http://bit.ly/ekkeBTLEapp

Maybe you should just do bluetooth turn off/on programmaticaly from your app, before using of an BLE.

A BTLE port towards WinRT is currently going on and we hope to have it supported with Qt 5.8. Please note that this does not include classic / desktop Windows, as the APIset is not available for this platform.

@csanders Bump this. I've got the same issue. Anyone at Qt able to shed some light on why it's so difficult to perform these features on iOS? I'm assuming it's something to do with Apple's MFi?

Thx, i will give it a try