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Picture of See Sound Waves Using Colored Light (RGB LED)

Here you can see sound waves and observe the interference patterns made by two or more transducers as the spacing between them is varied. (Leftmost, interference pattern with two microphones at 40,000 cycles per second; top right, single microphone at 3520 cps; bottom right, single microphone at 7040cps).

The sound waves drive a color LED, and the color is the phase of the wave, and the brightness is the amplitude.

An X-Y plotter is used to plot out the sound waves and conduct experiments on phenomenological augmented reality ("Real Reality"™), by way of a Sequential Wave Imprinting Machine (SWIM).


First I'd like to acknowledge the many people who have helped with this project that started out as a childhood hobby of mine, photographing radio waves and sound waves ( Thank you to many past and present students, including Ryan, Max, Alex, Arkin, Sen, and Jackson, and others in MannLab, including Kyle and Daniel. Thanks also to Stephanie (age 12) for the observation that the phase of ultrasonic transducers is random, and for help in devising a method of sorting them by phase into two piles: ``Stephative'' (Stephanie positive) and ``Stegative'' (Stephanie negative). Thanks to Arkin, Visionertech, Shenzhen Investment Holdings, and Professor Wang (SYSU).

Step 1: Principle of Using Colors to Represent Waves

Picture of Principle of Using Colors to Represent Waves

The basic idea is to use color to represent waves, such as sound waves.

Here we see a simple example in which I have used color to show electrical waves.

This allows us to visualize, for example, the Fourier transform, or any other wave-based electrical signal, visually.

I used this as a book cover that I designed [Advances in Machine Vision, 380pp, Apr 1992], along with some contributed chapters to the book.

in Step 1: Principle of Using Colors to Represent Waves, my scrolling wheel makes the image...breathe?
yup, that's an optical illusion.
there are many more like this too!
Sneaky! Did very many others catch it? So,what causes it? I'm guessing it's a glitch due to difference between monitor refresh speed while using mouse's scrolling wheel, and retina to brain data input speed. Am I close? It reminds me of some of the optical illusions people on LSD mistake for hallucinations, like walls "breathing", color trails, rubbery bending pencils, et al.
Not sure, but sounds like a very accurate explanation! : )
lol i just noticed that
search for "moving optical illusions"
on google and you will see many more.
I don't know what the light source is. What is it?
How do you get a 1:1 volumetric map?
denver27 days ago
Wow, so cool!
arabyshop28 days ago
very cool Steve, great images!

reminiciset of wave machine we used in my HS physical science class.

SteveMann (author)  itsmescotty1 year ago

Tell me more about the wave machine used in your HS physical science class. Was this a PAR (Princeton Applied Research) wave machine?

betwys11 year ago

I was sad to find that this is not real time visualization of sound waves, but (If I have it right) a photographic technique like schlieran

SteveMann (author)  betwys11 year ago

The exposure time depends on the speed of movement of the robotic mechanism, itself limited by the integration time of the lock in amplifier, and by the requirement for safety and longevity of the robotic mechanism. It is realtime, but just on whatever scale is set by the system design requirements (higher frequencies can update faster, for example). When done in VR, it updates around 60 frames per second, although the original scan still requires whatever the exposure time is set by other constraints. You might find some of my research papers useful in this context.

dresch1 year ago

Have you considered using a line of MEMS microphones and LEDs, then you won't need motion control just electronic switching. Cost does not seem that prohibitive to put 10 to 50 pairs in a line...

Very cool Instructable. Need to study that lock-in amplifier circuit!

SteveMann (author)  dresch1 year ago

Yes, we designed a board with 100 microphones every 7.5 inches.

Note by way of comparison the machine we put together for this Instructable has a resolution of about 10,000 pixels across by 8,000 pixels high, i.e. much better.

So in order to study scientific phenomena, I prefer to SWIM out a 2D space rather than the linear array SWIM, even though the original SWIM that I made in my childhood 43 years ago used a linear array (of only 35 elements = super low resolution):

makendo1 year ago

very cool Steve, great images!

SteveMann (author)  makendo1 year ago

Thanks for the kind words, Scott!

Perhaps you can vote for me.

Looking forward to keeping in touch!