I'd like to write a simulation of a Cymatic Tonoscope.
I plan to create a physical model of a circular membrane, sand will be sprinkled on top of it. When a person speaks into a microphone the membrane will vibrate causing the sand to form standing wave patterns.
Obviously this will be done in real time.
Any ideas guys? I really want to write this :)
All the best,
Carl.
Amazing idea for a project Carl.
The way I see it you have two routes.
- Do a full finite element physical model of a circular lamina
and measure the amplitude at many points on the surface. The sand falls into minima nodes iirc .
- Cheat. Create the visuals by mapping the known standing
waves of various modes but missing out the "actually building a physical model" part.
The latter is more feasible for a real-time simulation, but possibly more difficult than using the model. You'll need a much better mathematician than me to help you work out the mapping.
In the worst case you could "sample" the data, do a frequency sweep and fit an equation to each standing pattern which is indexed by the frequency input from your voice.
Hope that helps. Imho it's quite a challenging project to pull off, so best of luck.
On Tue, 27 Mar 2007 15:23:34 +0100 "Carl Knott" iamfromspacebaby@gmail.com wrote:
I'd like to write a simulation of a Cymatic Tonoscope.
I plan to create a physical model of a circular membrane, sand will be sprinkled on top of it. When a person speaks into a microphone the membrane will vibrate causing the sand to form standing wave patterns.
Obviously this will be done in real time.
Any ideas guys? I really want to write this :)
All the best,
Carl.
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Hallo, padawan12 hat gesagt: // padawan12 wrote:
Amazing idea for a project Carl.
The way I see it you have two routes.
- Do a full finite element physical model of a circular lamina
and measure the amplitude at many points on the surface. The sand falls into minima nodes iirc .
- Cheat. Create the visuals by mapping the known standing
waves of various modes but missing out the "actually building a physical model" part.
Actually approach 2) might be less cheating than approach 1) because with a finite element simulation, maybe made with msd, your grid topology may introduce unwanted distortions, especially with a circular membrane. Interesting question.
Ciao
Frank Barknecht _ ______footils.org_ __goto10.org__
On 3/27/07, Frank Barknecht fbar@footils.org wrote:
Hallo, padawan12 hat gesagt: // padawan12 wrote:
Amazing idea for a project Carl.
Yeah. Cool!
The way I see it you have two routes.
- Do a full finite element physical model of a circular lamina
and measure the amplitude at many points on the surface. The sand falls into minima nodes iirc .
This might be overkill. How about finite-difference methods instead? Instead of doing the precise finite element method, use a fixed grid of points (say arranged in a circular pattern), and use an update equation. The visual difference should be negligible, since people would not be able to verify the frequency of the simulation. In either case, the solutions of finite-element or finite-difference methods are given as solutions to a matrix equation, dependent on boundary conditions. Instead of solving matrix equations, you can just use update equations, which will be faster and less precise. It will still represent the standing waves pretty well.
- Cheat. Create the visuals by mapping the known standing
waves of various modes but missing out the "actually building a physical model" part.
Actually approach 2) might be less cheating than approach 1) because with a finite element simulation, maybe made with msd, your grid topology may introduce unwanted distortions, especially with a circular membrane. Interesting question.
Sort of like having a couple of band-pass filters to break up the speech frequencies, and then map them onto the corresponding Chaladni figures super-imposed on each other.
The sand still could be tricky... you would maybe have the individual particles at random locations, initially, and compute a gradient of the vibrations to determine movements. A different visual effect would be to move the sand particles in random directions, by an amount proportional to the amplitude. The sand would still seem to move randomly, just faster over the vibrating surfaces.
Chuck
Martin Peach wrote:
Charles Henry wrote:
The sand still could be tricky... you would maybe have the individual particles at random locations, initially, and compute a gradient of the vibrations to determine movements.
When I saw the sand arranging itself I thought "cellular automaton".
Martin
I thought that the patterns and the various configurations in chladni figures depend on the materials used.
Am I wrong?
c.
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Cesare Marilungo wrote:
Martin Peach wrote:
Charles Henry wrote:
The sand still could be tricky... you would maybe have the individual particles at random locations, initially, and compute a gradient of the vibrations to determine movements.
When I saw the sand arranging itself I thought "cellular automaton".
Martin
I thought that the patterns and the various configurations in chladni figures depend on the materials used.
Am I wrong?
c.
The patterns probably depend on the stiffness of the plate/membrane as well as its shape, and the grain size and density of the sand. By analogy with the Karplus-Strong vibrating string, which is a one-dimensional CA, usually the stiffness of the string is ignored. Also, the grain size would be the same as the pixel size and the density would be ignored. I see it as being like 2D version of the KS waveguide, with the superimposed grains moving in each time step towards the neighbour whose vertical acceleration is the lowest among 8 neighbours. Apart from the difficulty of doing a 2D KS, there is the further complication of an external frequency forcing (maybe introduced at the edges of the plate?).
Martin
The patterns probably depend on the stiffness of the plate/membrane as well as its shape, and the grain size and density of the sand.
It should depend on stiffness, density and shape. The speed of sound in a material is sqrt(stiffness/density). The partial differential equation for waves depends on these two constants, and the amplitude of forcing. The units are a little tricky (and they are different depending on the number of dimensions) I have been engrossed by this idea, since I read it on the list :) I'm sure you'll have a lot to research to make this work, and I really hope you make something cool!
By analogy with the Karplus-Strong vibrating string, which is a one-dimensional CA, usually the stiffness of the string is ignored. Also, the grain size would be the same as the pixel size and the density would be ignored. I see it as being like 2D version of the KS waveguide, with the superimposed grains moving in each time step towards the neighbour whose vertical acceleration is the lowest among 8 neighbours. Apart from the difficulty of doing a 2D KS, there is the further complication of an external frequency forcing (maybe introduced at the edges of the plate?).
Martin
I see the edges as being different kinds of boundary conditions, Dirichlet, Neumann, and Robin. Dirichlet -> amplitude is zero at the boundary (reflected waves are 180 deg out of phase) Neuman -> 1st deriviative is zero at the boundary (reflected waves are in phase with incoming waves) Robin -> 1st order differential equation (specifies a constant phase difference between incoming/reflected waves)
Maybe this helps. ElectricPete offers a shortcut to the first two modes of a rectangular plate in terms of density, elasticity and two material constants.
http://www.eng-tips.com/viewthread.cfm?qid=150916&page=12
On Wed, 28 Mar 2007 10:12:32 -0500 "Charles Henry" czhenry@gmail.com wrote:
Robin -> 1st order differential equation (specifies a constant phase difference between incoming/reflected waves)
for accuracy sake.... the phase difference is dependent on frequency (it works like an impedance)
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Am 28.03.2007 um 16:32 schrieb Martin Peach:
The patterns probably depend on the stiffness of the plate/membrane as well as its shape, and the grain size and density of the sand. By
actually dr. hans jenny used a special pollen (lycopodium spores),
not sand. because sand has a crystalline structure while the pollen
is a perfect sphere. (by the way lycopodium is also a homeopathic
substance associated with the male sexuality, comes up on google...)
check out those vids (round membrane here, nasty sound) :
http://www.harmonyera.com/videos/HJenny01.avi http://www.harmonyera.com/videos/HJenny02.avi http://www.harmonyera.com/videos/HJenny03.avi http://www.harmonyera.com/videos/HJenny04.avi
max
Frank Barknecht wrote:
Hallo, padawan12 hat gesagt: // padawan12 wrote:
Amazing idea for a project Carl.
The way I see it you have two routes.
- Do a full finite element physical model of a circular lamina
and measure the amplitude at many points on the surface. The sand falls into minima nodes iirc .
- Cheat. Create the visuals by mapping the known standing
waves of various modes but missing out the "actually building a physical model" part.
Actually approach 2) might be less cheating than approach 1) because with a finite element simulation, maybe made with msd, your grid topology may introduce unwanted distortions, especially with a circular membrane. Interesting question.
Ciao
To me this whole idea seems rather difficult, if not impossible, to implement. We are talking about interactions happening at the atomic level of matter here.
And it would be far more interesting to sample real cymatic figures in the physical world and reuse them for synthesis or whatever.
Just my two cents.
Ciao,
c.
To me this whole idea seems rather difficult, if not impossible, to implement. We are talking about interactions happening at the atomic level of matter here.
It's not really the atomic level that we have to implement. You can actually treat the material as continuous, and sampled at discrete points so that the wavelengths are much, much larger than the distance between points, and the steps in time are small compared to the size of the wavelength/(wave speed). In the limit as the difference between spatial samples and temporal samples goes to 0, you get something that represents the real physics of the problem. The real question is just what's good enough?
And it would be far more interesting to sample real cymatic figures in the physical world and reuse them for synthesis or whatever.
I really liked the video link you posted for the figures. The rectangular plate has some cool symmetries, that would be better than a circular membrane. Plus, it's easier to do simulations of partial differential equations in rectangular coords rather than polar coords.
Cesare Marilungo wrote:
Frank Barknecht wrote:
Hallo, padawan12 hat gesagt: // padawan12 wrote:
Amazing idea for a project Carl.
The way I see it you have two routes.
- Do a full finite element physical model of a circular lamina
and measure the amplitude at many points on the surface. The sand falls into minima nodes iirc .
- Cheat. Create the visuals by mapping the known standing
waves of various modes but missing out the "actually building a physical model" part.
Actually approach 2) might be less cheating than approach 1) because with a finite element simulation, maybe made with msd, your grid topology may introduce unwanted distortions, especially with a circular membrane. Interesting question.
Ciao
To me this whole idea seems rather difficult, if not impossible, to implement. We are talking about interactions happening at the atomic level of matter here.
And it would be far more interesting to sample real cymatic figures in the physical world and reuse them for synthesis or whatever.
Just my two cents.
Ciao,
c.
Interesting project.
Here is a Gem version of the basics.
Also I'm trying to make one with [pix_sig2pix~]
mhv/ Steffen Leve Poulsen
Carl Knott skrev:
I'd like to write a simulation of a Cymatic Tonoscope.
I plan to create a physical model of a circular membrane, sand will be sprinkled on top of it. When a person speaks into a microphone the membrane will vibrate causing the sand to form standing wave patterns.
Obviously this will be done in real time.
Any ideas guys? I really want to write this :)
All the best,
Carl.
ooooooopppppppps
attached Chladni.pd
Carl Knott skrev:
I'd like to write a simulation of a Cymatic Tonoscope.
I plan to create a physical model of a circular membrane, sand will be sprinkled on top of it. When a person speaks into a microphone the membrane will vibrate causing the sand to form standing wave patterns.
Obviously this will be done in real time.
Any ideas guys? I really want to write this :)
All the best,
Carl.
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
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Carl Knott -
Cesare Marilungo -
Charles Henry -
Frank Barknecht -
Martin Peach -
Max Neupert -
padawan12 -
Steffen Leve Poulsen