LEDControl BLE.scanForUuid() don't work, BLE.scan() does work

Official Hardware Nano Family Nano 33 BLE
1

Hi!

I'm setting up two BLE 33 nano's back to back. To get started I'm trying to just re-use the included example LED and LedControl. However when scanning for the specific UUID, I'm never finding the LED board. But removing the spesific scan and just looking for the localName == LED it's working. Anybody else having trouble with the BLE.scanForUuid function?

Starting LED with UUID

BLEService ledService("19B10000-E8F2-537E-4F6C-D104768A1214"); // BLE LED Service

// BLE LED Switch Characteristic - custom 128-bit UUID, read and writable by central
BLEByteCharacteristic switchCharacteristic("19B10001-E8F2-537E-4F6C-D104768A1214", BLERead | BLEWrite);

On the LedControll side

// start scanning for peripherals
BLE.scanForUuid("19b10000-e8f2-537e-4f6c-d104768a1214"); // fails
BLE.scan();  // Works

Output when using the working variant. And yes the reciving nano blinks the LED as expected.

Found ec:35:86:45:23:ad '' 
Found 40:cb:c0:db:16:2f '' 
Found d7:92:d0:1e:6c:ca 'LED' 19b10000-e8f2-537e-4f6c-d104768a1214
Connecting ...
Connected
Discovering attributes ...
Attributes discovered
button pressed
button released
button pressed
2

The example with scanForUuid works for me when I start the LED after starting LEDcontrol.

There are some issues, but I haven’t figured out exactly where they come from. When the connection is interrupted by disabling one side the other side does not recognize that. The .connected() function does only work when I used an app to connect and disconnect properly. When I just kill the app while connected this is not recognized.

So, when I power up the two nodes in the right sequence everything works, but I cannot get the nodes to reconnect. I tried a few things to restart the scan but so far, no luck.

3

I was hoping to find that it was me doing something wring here. But OK, some comfort to be found in not being alone with the issue I guess.

I need the nano's to be powerd on independant of each other. And quickly establish a reliable connection. Hopefully someone will chime in here with a better solution. Given the code examples I'm under the impression that they should work that way back to back.