notifyChar = null

edited January 2017 in C#
I'm testing the Freefall app but it crashes when I click on the MetaWear. After some debugging it crashes at line 126 in DetectorSetup.xaml.cs.

var notifyChar = selectedDevice.GetGattService(GattCharGuid.METAWEAR_NOTIFY_CHAR.serviceGuid).GetCharacteristics(GattCharGuid.METAWEAR_NOTIFY_CHAR.guid).FirstOrDefault();

And the value of notifyChar is null. Any help to debug this problem would be appreciated.


  • It looks like it's a driver issue with your bt adapter.  You can try re-pairing the device and/or reinstalling the drivers.
  • I've tried re-pairing many times. We have one Windows 10 laptop where the Freefall works but not on another laptop. It crashes at the line mentioned above. Do you know of the driver version that we should test with?
  • No, drivers vary depending on hardware.  You can check the manufacturer's website or use the Windows provided drivers.

    Are both laptops running the same Windows 10 build?
  • No. The working laptop is running the mainline version of Windows 10 and the non-working laptop is running an "insider preview" version of Windows 10.  

    I am also running the app on two Raspberry Pi's, which both don't work either. They crash at the same line. One Raspberry Pi is running the mainline Windows 10 IoT ans the other one is running "insider preview" of Windows 10 IoT.
  • Unfortunately there really isn't anything that can be done other than to check the drivers and try re-pairing devices.  Do the erred Win10 machines at least recognize the MetaWear service GUID?
  • Yes, both laptops recognize the GUID. Pairing is successful, but it fails at notifyChar as I mentioned above.
This discussion has been closed.