I had my Chickering Ampico restored and had one of Bob Hunt & Herb
Lindahl's Virtual Roll systems installed.  Since I use Android mobile
devices I wanted to use them to control the Virtual Roll rather than
a PC or an Apple product which I believe several people have done.
For the benefit of others who might like to do the same, here is what
worked for me.

The hardware interface is an iRig MIDI 2 MIDI interface.  This provides
a micro USB connector to the tablet or phone (Samsung Galaxy Tab S and
Samsung Galaxy Note 5) and links to a standard MIDI cable which will
plug to the Virtual Roll on the piano.

The player software is an app called MIDI Voyager Pro, which is available
through the Google Play App store for a cost of $4 (yes, only $4).  That
is all it took.  It works fine with Spencer Chase's Ampico e-roll files.

By hooking the phone to the piano, then using the Samsung Sidesync app,
which allows you to wirelessly connect your phone and tablet, I was able
to control the app on the phone through the tablet, which allowed me to
have complete control of the piano wirelessly from the tablet.

I expect the combination would work with other brands of Android tablets
and phones as long as they support the OTG USB standard, but the models
listed are all that I have tested.  I hope others find this information
useful.

Deane Shepard