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intel-iot-devkit / tinyb

TinyB exposes the BLE GATT API for C++, Java and other languages, using BlueZ over DBus.
MIT License
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How to handle multiple devices at once #156

Open wiesener opened 5 years ago

wiesener commented 5 years ago

Hi I would like to connect to more than one BLE device via tinyb. My current workflow is the following:

// First device manager = BluetoothManager::get_bluetooth_manager(); manager->start_discovery() auto foundServices = manager->get_services(); this->btdev = manager->find(...); btdev->connect() this->nus_service = btdev->find(&(this->nus_service_uuid), std::chrono::seconds((timeout / 10))); manager->stop_discovery() this->nus_char_tx = this->nus_service->find(...); this->nus_char_rx = this->nus_service->find(...);

// Second device manager = BluetoothManager::get_bluetooth_manager(); manager->start_discovery() auto foundServices = manager->get_services(); this->btdev = manager->find(...); btdev->connect() this->nus_service = btdev->find(&(this->nus_service_uuid), std::chrono::seconds((timeout / 10))); manager->stop_discovery() this->nus_char_tx = this->nus_service->find(...); this->nus_char_rx = this->nus_service->find(...);

But as soon as I start discovery again it crashes saying that it is in use. Although I do not store the manager permanently only the device is created and stored in the object. Is there an example how to handle several connections.

petreeftime commented 5 years ago

You don't need to stop discovery and start it again unless there is a large gap in time between adding the two devices. You also don't have to get_bluetooth_manager more than once. The underlying object will always be the same.

Unfortunately, this issue is on the BlueZ side, and I don't know if there's a nice way to hide it in TinyB.

It definitely works with multiple devices at once, I tested this at some point, but I didn't add this as an example since it was very specific.

wiesener commented 5 years ago

Since I've separated it into an Interface class I need to get two times the manager. But I'am only holding the same pointer. Would it be wrong to stop discovery and then restart it?

wiesener commented 5 years ago

"Unfortunately, this issue is on the BlueZ side, and I don't know if there's a nice way to hide it in TinyB." Which specific part of the issues you mean?

wiesener commented 5 years ago

Okay cool, leaving the manager in discovering mode makes everything run more performant and I can now connect to several devices at once (So far tested only two of them). But anyway cool. Thanks