in a background project, I'm trying out an idea that will bring a rotary control to the motor pot interface and just plug in. yes, using voltage levels as an interface (which is why i was playing with 8pin dac chips lately).
the problem with rotaries is that most systems are not fast enough to keep up. but if I can get a 2nd small cpu to front-end this, not only will it (hopefully) never miss a fast-turn pulse-train but it will plugin directly and not need any code changes on the main lcduino.
the rotary can replace the pot for volume and wherever the pot is used. but there is still the issue of buttons.
on my sercona box, I have a port expander that supports the front buttons but that needed code to be written and some soldering of new perf boards to be done. I gather that few diyers want to do this and would only want to if there was a ready made green pc board for this.
one problem with buttons and diy is that the mounting can get tricky and if you assume a layout and mount the buttons on the board, this limits the chassis size and style you can use. button grids don't usually find their way on diy's.
I didn't go with a full grid, just a few (4) buttons and 2 rotaries. one for volume and one for input selection. the rotary for input selection would NOT be 'free' from the ir remote hack, of course. THAT would have to be new code written or a new hardware interface.
also worth mentioning is that rotaries mostly suck. the cheap dollar ones really do suck and they bounce a lot. their feel is lousy, they are meant for cheap lightweight plastic knobs and heavy metal knobs cause typical RE's to wobble. its not a pretty picture. then, there are expensive ones that are hundreds of dollars. anyone ready to spend that? didn't think so
the cheap ones are only a dozen or two pulses per rev. that means you have to turn and turn and turn to get anywhere. otoh, 'touch ups' where you only want to make small changes to your vol setting are actually more pleasant on these than a real pot (personal style, though).
mechanics are the hard part. getting GOOD motor pots is hard, getting GOOD rotaries is even harder. mounting a grid of buttons is challenging.