Zhao Yitian

HI the OTG cable has a lot of models, you need to check with your mobile manufacturer to see which one is compatible.
The Xkey Piano only detected Xkey USB cable automatically. If you use WIDI BUD, please go to 3 lines icon on the top left and select WIDI BUD as MIDI Input. Please check screen shot for reference.
Xkey Piano w/ WIDI BUD connection