LDR ideas

[Francois Dion]

steve.ridley at bbc.co.uk wrote:

> 1.   A light controlled filter

I had done a pair of modules to light control an SH-101 and used it in
controlled environments (studio) and live. However live as you mention,
the lightning does vary quite a bit. No problem whatsoever with 50/60Hz
modulation in my case. About a year ago in a live performance someone
had asked me after the show if it was some kind of theremin (it was not
obvious that the SH-101 was the sound source), but generally people
would just stare...

> before.  I know of ancient tone generators based on LDRs and
> spinning glass disks with patterns painted on - went noisy due
> to dust, insects etc.  Daphne Oram did similar things with film.

An american by the name of Sammis patented the first use of 35mm film in
1936. Louis Lavalée played with that idea too that same year but instead
recording the performance (the notes) on it, the basis for all of this
being the Celluphone of Pierre Toulon. The mattel Optigan used a
transparent disk on the same concept.

> There are a few serious problems with all of these, and the
> worst one will be the light source.  Under artificial AC lighting,
> there will be 50/60Hz modulation, especially with flourescent
> lights.  Under stage lighting conditions things will fairly wild!

Ciao,
Francois Dion (francois at hyperreal.org)