I have recently added keyboard controls to dynamically set the transposition in my Gestural Music Sequencer. I set it up like a piano keyboard, so that “Q” is the key of C, “2” is C sharp and so on. In this example I have the application set to to play a minor pentatonic scale. This makes it quite clear when the key changes. In this case I’m modulating between C and F sharp. I also started with a slower note duration, then switched to a faster one. I would not classify this as a very musical performance. This was part of a test to make sure that all of the transposition key controls were operating properly.
Transposition Controls (C to F# Modulation)