Nano BLE 33 and volume up button example; AVRCP

[andrewa]

If we link a Nano BLE 33 to a smartphone, in theory, you can use the Nano BLE 33 as an HID device; this was mentioned at the end of this post:

viewtopic.php?f=60&t=187266

Great! However, however, how does one do something like send a 'volume up' signal (if you are in the camera app on the smartphone, you can take a picture). Is there an Ascii code or code sequence for volume up? Some USB keyboards to have volume up buttons, so I was wondering if there was an explicit sequence for that.

A bit of research narrows down seems to point to the path that one can use the AVRCP service, but I don't see an explicit example. Here's a good example of using the https://rootsaid.com/arduino-ble-example/ for the battery service. I think I've found something for the ESP32 here: https://github.com/pschatzmann/ESP32-A2DP; didn't know if there was an equivalent for the Nano BLE 33. There does seem to be this post, viewtopic.php?f=53&t=106158&p=532105&hi ... CP#p532105, but this is for the Flora BLE.