Re: Speech sensors?

[Leigh Palmer <palmer@sfu.ca>]

> > > > I once tried it with a 5mW HeNe laser and a photocell to detect
> > > > reflections from a vibrating window glass.  It didn't work for me
> > > > but it might work with an optical system to concentrate the
> > > > reflected light on the photocell and sensitive amplifiers at  the
> receiving end.
> > > > Herb Gottlieb
> On Sat, 27 Dec 1997 01:01:59 +0100 (MET) msantos@etse.urv.es writes:
> > How does this work? what is the photocell for?
> > msntos@etse.urv.es
>
> The idea was to aim a laser beam at a vibrating window and receive the
> modulated reflections from the window by a photocell. Photocells convert
> light waves into electric waves which can then be amplified and converted
> into sound waves by a radio speaker.

What means did you use to detect the modulation? It seems to me that one
would have to look for some variant of an optical lever arrangement to
get a signal from the window membrane. Merely receiving the reflection
won't do the trick.

Leigh