As an aside that might be of interest to some - if you want to build a machine out of steppers, servos, digital output pins etc, and you want it to operate under tight timing constraints, and you want to avoid getting your hands dirty with finicky embedded programming, the Klipper project - nominally a 3D printer system - is sufficiently modular to be an excellent base. The developer documentation isn't perfect, but it's pretty straightforward to write new modules for it, all in Python, and it performs extremely well.