[Geoff Bacon]

It could be that the pedal is using an old version of Bluetooth - I know my tablet will only support BLE (Bluetooth Low Energy?) so it won't see the much cheaper "old" BT devices. A couple of years ago I was looking at trying to adapt a mouse but gave up in the end because the BLE versions were £30+ (probably cheaper now)

I suggest you try to get your Donner pedal to work with your device outside of MobileSheets e.g. to turn pages in a pdf viewer
Should you get it working then it should be possible to use in MS.

I googled an ONN tablet, possibly not the model you have, and it said it used BT 4.0. Suggest you google your exact model of Donner pedal to see what that uses. If it is less then 4.0 then I believe it won't work.

Geoff