Over the years I have used a lot of different systems to send and play
MIDI files on my instruments.  Some may be interested in my latest setup.

On an old Android phone (with OTG output) I have installed a program
called Midi Voyager.  From a bystander's viewpoint this program is
very satisfying since it displays, in real time, a piano roll view of
the MIDI file being played.

A generic OTG cable is plugged into the phone and a generic USB-to-MIDI
cable is plugged into the OTG cable.  Finally, the output from the
USB-to-MIDI cable is plugged into a wireless MIDI transmitter and a
wireless receiver is connected to the MIDI instrument.  In my particular
setup I cut and re-soldered most of the cables to shorten them to make
the whole setup easily hand-held.

The MIDI transmitter/receiver I used is midiBeam by pandaMidi, cost
approximately $160 ( http://pandamidi.com/ ).  Although not expensive
it seems to work very well.  If this seems of any interest I could
post some photos.

Phil Dayson
Vancouver, British Columbia, Canada

 [ OTG is short for "USB On-The-Go".  -- Robbie