Find Hub by Name

[tthiery]

By BLE advertisment name

Lessons Learnt from #49

[tthiery]

BLE advertisment does not include a name field. The device actually has it. Query device during discovery

[dlech]

Actually, the advertisement data does include "Local Name" in the scan response data.

[tthiery]

Thanks for noticing. I also looked into it. The LocalName was empty for me. I will have a second look into it. Maybe I need to adjust the watcher or something else so the field gets populated.

[GianCann]

It use the ShortName.

[GianCann]

@tthiery take a look here: https://github.com/tessel/bleadvertise

[dlech]

There are two different advertisements, one with the ScanResponse flag set and one without (https://docs.microsoft.com/en-us/uwp/api/windows.devices.bluetooth.advertisement.bluetoothleadvertisementtype?view=winrt-19041). I forget the terminology, but I think you have to do something like an "active" scan to get the scan response type data.

[tthiery]

After reading, testing etc ... I came to a surprising end ;)

So WinRT API is a bit ... strange.

• I was actually actively scanning for advertisments watcher.ScanningMode = BluetoothLEScanningMode.Active;.
• The advertisment LocalName would need to be in a data section with DataType 8 (shortened) or 9 (complete). However, the TechnicMediumHub only returns 1 (Flags), 7 (CompleteService128BitUuids) and 255 (ManufacturerSpecificData). I actually do not receive any ScanResponse flagged advertisment not alone with that ;)
• Then I was trying to install a watcher for the device from the windows internal registry of devices (unrelated to BT itself). That was painful and I failed doing it. I am not alone with that ;). I know it somehow works .. but it is late.
• Then I looked it from a different perspective: If Windows has a device (and it has it) representing my hub, why I cannot retrieve it by a method using the Bluetooth Address. This again lead to the following code ...

  using (var device = BluetoothLEDevice.FromBluetoothAddressAsync(eventArgs.BluetoothAddress).AsTask().Result)
  {
    info.Name = device.Name;
  }

  ... which is literally what I did before the complete excurse. According to the docs this should not even create a connection.

Strange is only: How does Windows know the name? Maybe it cuts the the data sections.

I let this open for another day or two ... some more experiments ... but i may let it settle like that.

[tthiery]

Close it for now. Have tried it again but could not achieve more.