Or take it a step further.  If you are using a microcontroller in the equation then why not let it do some of the work for you.

I cannot remember but I think the distances between the antenna and the hand relative to the pitch is ... I don't know what the word is or how to explain what I mean... logarithmic is it?  

For example, from 110Hz to 220Hz, A to A, is one octave or 12 steps on a piano.  From 220Hz to 440Hz is still another A to A octave and 12 steps on a piano or any other instrument.  But the difference between the two has gone from 220-110=110 to 220-440=220.  Logarithmic is that?

But the difference between the steps on a piano are based on distance and therefore equal.  Every key is the same width, of course.  (-:

I'm not sure how the pitch goes on a Theremin but I think it is logarithmic rather than linear.  

My idea is what would a Theremin be like to play if it were linear like a piano with each step being x number of millimeters distance to the antenna?  

A PIC could do the math to make that happen.  I think for me at least I would have to try each one to see which is easier.  But this is a cool topic, for me at least. (-:

What do you think?

-Lindy

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Robert Rolf
Sent: 2. joulukuuta 2005 0:05
To: Microcontroller discussion list - Public.
Subject: Re: [OT] Theremins


I rather like the idea of an optical thermin.
They'd be just as hard to play, but would be easier for the
digital geek to build.

Ranging could be as simple as a modulated IR source with
a tuned amplifier on the photodetector so that you get a linearish
response to intensity vs hand distance. (1/R^2). Then simple math
to scale to a linear note number times 12th root of 2 note intervals.

You could even cheat and have the PIC 'fix' your bad pitch just
as modern DSPs do for today's not so good singers.


Robert


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