[sdiy] Tonewheel questions

[john mahoney]

---- Original Message ----- 

> On Fri, May 28, 2004 at 07:27:27AM -0700, Harry Bissell Jr wrote:
> > My method would be to use retro-reflective optical
> > sensors on a 12" diameter cardboard disk carried on
> > a turntable platter.  speed control would be
> > excellent.
> > You could use white cardboard and black magic marker.
> > Different frequencies could occupy different positions
> > on the disk
>
> Sounds like an Optigon.

Um, yeah, as I wrote this morning:
> Optical tonewheels can also use black & white patterns (reflective) or
> transparent wheels with opaque masks (transmissive). Actually, you can use
> shades of gray, too. A radial array ... in white-to-black gradient would
> create a sawtooth. Look into optical soundtracks of movie theatre
projectors
> for more info. Probably treading on some Optigan patents, now!

Doesn't have to be strictly black & white, either.
--
john