Pragmatics of a polyphonic calculator (chapter 2)

[Garth Wilson]

Some projects are just for the fun of it. Why would anyone need a model railroad locomotive, especially a steam engine? But enthusiasts go to great expense to make operational ones, and they enjoy it immensely.

A users'-group contribution for the HP-71 in the 1980's was the LEX file NOISE which could make the beeper do a wide range of sounds, including music. Through HPIL, you could sync two or more together and have them play various voices of a piece of music, for polyphonic sound.

I don't see anything particularly wrong with your choice of specifications above; but why the arbitrary numbers? and why color? (Color is always a battery hog, because it cannot be reflective only. It requires that you continuously power a light source, unlike B&W. There goes the battery life. Written music is never in color anyway.) Note (haha) that there's no need for floating-point for this application (unless you really want it to be a calculator too). I have an article on scaled-integer and how it can be used very effectively in situations that most people think require floating-point. Note also that you can mix sounds digitally with simple addition before sending the result to a single D/A converter, so you don't need a hardware analog mixer. A hardware multiplier would be good though. I expect you'll want more memory though, or at least serial flash storage space.

FWIW, I would be able do what you're talking about with my home-made 65c02 workbench computer that I use as a Swiss army knife of the workbench for controlling processes, taking data, etc.. I also put a MIDI port on it, although I've never used that part for anything serious. (I'm a musician, cellist, and had visions of composing keyboard and orchestral music that beyond my ability to play, editing it, and playing it through my MIDI keyboard. I never did it, and now my interest is gone.) The piezoelectric beeper on the board definitely does not have music-worthy sound quality, but the D/A converter and output amplifier does; and if I use MIDI, then the sound is generated by the musical keyboard itself per the instructions from the computer.