At some point I upgraded my guitar synth unit to a Roland GR-55. This is a fun thing, but has one annoying flaw. Unlikely previous units I had owned, if I held down the button on the guitar to change patch, it would only advance by a single patch.
What I would expect to have happen, and what is the norm with most selection UIs, is that after a short delay, the GR-55 interpret the held button as a request to keep scrolling through the patches. Pressing the button 10 times to go from e.g. patch 13 to 23 was so incredibly annoying, I had to do something about it. I acquired a bunch of minuscule knock-off ATtiny85 microcontrollers and went from there.
Then it was just a matter of writing some trivially simple software that when I held a button, manually issued multiple virtual button presses. Wiring it in was pretty straightforward, just using a couple of diodes and piggy backing off the GK module’s power supply.