I've got a Dotstar strip, a piano, and an UNO(w a usb host shield). I can get and properly translate data from the piano to the UNO, so I'm definitely getting the right information to the board. When i hardcode input values into my code it reacts appropriately, so I know my code works. However, when I attempt to take data from the USB piano keyboard and light a corresponding LED, the whole strip lights up blue and green and flashes brightly between them. This happens before I even hit a key on the keyboard. When I hit a key, the correct light lights up for roughly a milisecond before returning to flashing green or blue.
I feel like there's some electrical concept that I'm not getting- I've got the MIDI information correctly making it to the board, and it can correctly control the LEDs. I don't know where it could be getting the data that's causing it to do this.