> Hi,
> What was the, year, date and number of the "Opto. Projects" note book?
> Thanks
> N. Howie.
>
****************************************************************************
> ******
> ----- Original Message -----
> From: Bill Perry <Prinsess@bigfoot.com>
> To: <interact@Keelynet.com>
> Sent: Monday, 21 February 2000 20:10
> Subject: Re: Flame speaker
>
>
> > Hi, All!!!
> > I was reading the "Optoelectronics Projects" one of the "Engineer's
> > Mini-Notebook" segments by Forrest M. Mims III. He describes a really
cool
> > project called a light listener that uses an Infrared photo-diode, which
> > modulates voltage input into a basic audio amplifier. This produces
really
> > nice sound effects. Buzzing from fluorescent lamps and TV screens/
> computer
> > monitors, ringing from car headlights when the car goes over bumps in
the
> > road, but the most intriguing sound was that of a steady candle flame
> > (produces a soft rushing sound).
> > I will be outfitting something similiar, except instead of a speaker
> or
> > earphone, the audio amp will be used to drive the electrostatic plates
for
> > the flame speaker. So this thing basically should provide a fair amount
of
> > feedback into the candle flame, and either increase the candle rushing
> noise
> > to normal audible levels, or possibly if you used the right amp
> > configuration, you could boost it in the right phase, and might increase
> the
> > burning of the flame to make it combost faster.
> > Thanks.
> > BillP
> > ----- Original Message -----
> > From: Jerry W. Decker <jdecker@keelynet.com>
> > To: <interact@keelynet.com>
> > Sent: Saturday, February 19, 2000 8:20 PM
> > Subject: Re: Flame speaker
> >
> >
> > > Hi Joseph et al!
> > >
> > > I was wondering how long it would be before someone
> > > mentioned that....<g>...flame speakers have been around
> > > since the 1800's....after all, flame is ionized so by
> > > using an electrostatic modulation, its a simple
> > > matter to jerk it back and forth at audio rates.
> > >
> > > They were even sold commercially as speakers back in the
> > > 1960's/1970's...I used to know a lawyer who had a pair
> > > he paid something like $1500 for them...they used propane
> > > gas to produce a flame, had two electrostatic deflection
> > > plates and a cavity to reflect the sound....the response
> > > is said to be from 0 up to light...<g>...I never heard
> > > them in operation.
> > >
> > > I don't the efficiency of those would be sufficient to
> > > fulfill the needs of the original post...everything
> > > resonates to every frequency, but is most efficient when
> > > near resonance....so even piezo transducers can carry all
> > > the frequencies you would need and would of course have
> > > a 'Q' at their maximum resonance.
> > >
> > > The Chladni tables, akin to the early 'eidophones', had
> > > sound sung or spoken into a horn that focused the sound
> > > onto a plate so it could vibrate and move sound and form
> > > the beautiful geometries now called 'cymatics'...so a
> > > speaker under such a surface or a piezo affixed to it
> > > could be driven to produce the many fascinating patterns.
> > >
> > > Of course one or more FIXED tones will generate very stable
> > > geometries although altering their relationships to each
> > > other will produce motion and even patterns such as swirls,
> > > expansion, etc...as so beautifully shown by the late Dr.
> > > Hans Jenny and more recently by Russian scientist Dr. Yuri
> > > Ivanov as posted here;
> > >
> > > http://216.60.190.54/spider/b-100e.htm
> > >
> > > another related post (after a fashion);
> > >
> > > http://www.escribe.com/science/keelynet/index.html?mID=2350
> > > t
> > >
> > > There are many marvelous ideas and devices that have long
> > > been lost or forgotten....such as 'musical fountains' where
> > > water jets spray at audio rates to make music simply as
> > > long as the fountain runs.
> > >
> > > Joseph Hiddink wrote:
> > > >
> > > > I remember reading something about the "Singing
> > > > Flame" in old Radio/Electronics magazines, and
> > > > that was already in the twenties or thirties. I
> > > > believe I read it in Hugo Gernsback Magazine.
> > > > So, how come that Nasa invented that?
> > > > Joe Hiddink vliegschotel@yahoo.com
> > > >
> > > > --- MILLENNIUM PROJECT <infonet@home.com> wrote:
> > > > > I searched nasa's site and couldn't find
> > > > > anything about flame speakers.I
> > > > > found one page with a definition of a flame
> > > > > speaker.Nothing else
> > > > > yet.Heres the page I found
> > > > >
> > > > http://www.exploratorium.edu/xref/exhibits/flame_speaker.html
> > > > > This website has some intresting index.
> > > > >
> > > > >
> > >
> ----------------------------------------------------------------------
> > > > > Warren writes:
> > > > > Yes, that is it. I will try and find my files
> > > > > on it and cut you a
> > > > > copy with diagrams. E-mail me if I should
> > > > > forget.
> > > > >
> > > > >
> > > > >
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