I spent my week traveling for Spring Break and didn't really do much work. That said I did end up thinking about things a little bit. I think I may have found a better solution for the lighting. Bliptronics makes 8mm LEDs that come on little PCBs that seem to be addressable over I2C. That means that I could just daisy chain a bunch of these guys together for power, ground, bus clock, and data wires, and I'll have a fully controllable RGB display. Writing to the display would just mean sending two bytes of color data to each LED in turn, and the little PCB would take care of applying the right voltages. It looks like these lights come at $1.79 a pop, maybe with a discount for bulk orders. They're not as convenient as the ring shaped lights I wrote about last week but these would be much more expressive. I've ordered some clear plastic caps so I can test the light transmitting abilities of the plastic.
I've also been thinking about some interaction stuff. Specifically, I'm starting to think that pitch would be hard to control on the thumbsticks. To make the pitch easily controllable, the available pitch range would have to be severely limited (to perhaps +1 and -1 semitone). While this is still workable, it would cut out a lot of the use cases. Pitch bends are used both for vibrato, requiring very small pitch adjustments, and for bangin' solos, which can employ huge pitch ranges (think of a guitar slide). I figure there are two options here. The first is to give each note it's own, short range pitch control, which would allow for different pitch adjustments to several notes at once, but has the draw back of a limited range. The second is to make a universal pitch control, perhaps manifested as a linear touch strip, which would allow for arbitrarily large pitch slides, but also has the potential for good vibrato. This is somewhat related to another problem I have to solve, which is a smart octave control - since the instrument only guarantees one octave per root note, the user will have to be able to shift octaves very quickly. Both of these factors point to a secondary set of controls for the user's non-dominant hand that can modulate effects and control global parameters. There are some ergonomics to consider.