3D Acoustic Manipulation: Seemingly-Unreal Levitation Using Soundwaves

Wow. [Yoichi Ochiai], [Takayuki Hoshi] and [Jun Rekimoto] are researchers from the University of Tokyo and the Nagoya Institute of Technology, and they have just learned how to airbend.

Using a series of standing ultrasound waves, it is possible to suspend small particles at the sound pressure nodes. The acoustic axis of the ultrasound beam is parallel to gravity, which also allows the objects to be manipulated along the fixed axis by varying the phase or frequencies of the sound. By adding a second ultrasound beam perpendicular to the first it is possible to localize the pressure node, or focal point, and levitate small objects around a 2D plane.

In their demonstrations they float foam particles, a resistor, an LED, they show off the waves using a piece of dry ice, and even manage to float a small screw.

Sound like crazy talk? Just watch the video.

Want to build your own? We covered a much more simple DIY Acoustic Levitator rig a few months ago.

[via Hardware-360]

32 thoughts on “3D Acoustic Manipulation: Seemingly-Unreal Levitation Using Soundwaves

  1. If the rotation of single objects in the center of the standing wave could be controlled, this might be an awesome pick and place solution.

    1. Dunno how you’d do that, I suppose you’d need to synthesise the sound wave on a computer, to get the wavefronts to move around the small distance needed. And you’d need, if it’s possible, several “nodes” you could move around, to grab either end of a component. Perhaps with an array of tiny speakers? They can do a lot nowadays with synthesis, same sortof thing as radio beam-forming with antenna arrays, but acoustically.

      For pick and place you’d also need to move the objects around quickly, without losing grip. Moving objects in air quickly is going to create ripples itself.

      Still this is a pretty good start.

  2. Is ultrasound harmless to ears? What about, I dunno, bones or something? I was thinking it’d be great to do this on a bigger scale with audible sound, like perhaps the gigantic satellite-testing speaker NASA have? It’s basically a speaker several feet across that tests things by vibrating them to atoms. That’d be something impressive, you might even be able to reach orbit with it!

    But thinking about loud sound danger made me wonder why sound is no longer dangerous just cos you can’t hear it? At around 40KHz the wavelength is about 8mm, wouldn’t that damage things? Would you need ultra-earguards?

    1. For what it’s worth: Whenever I Run several batches through my ultrasonic unit (around 100 watts),
      requiring a few hours of running time.
      I’ll notice a mild case of tinnitus for a few hours afterwards.

      1. I seen a news report regarding loud concerts.
        The Medical Professional stated that when you
        hear ringing in your ears after experiencing loud
        noise, that indicates damage has occurred to the
        ear.

    1. Yeah it’s funny how the USC slipped past my thinking.
      I’ve only run this one for extended time maybe 3 batches, So just really picked up on it the last time.
      But stop and think of the energy you’re dumping into
      a steel pan and it makes sense then.
      Generally I won’t run anything loud without hearing protection
      i.e. all my lawn equip, power tools,
      (this includes all your rotary tools guys)
      vacuum cleaners, etc.
      But having run the USC for several hours recently
      and definitely connecting that hearing issue
      has me now looking at isolating the unit from myself.
      I’m also a bit curious how well a properly inserted set of foam plugs work for USC noise.
      I’m currently using 3m tekk-29 db rated ones.
      Seems to be the best fit and attenuation for me.
      the foam has a slow enough recovery to allow getting it well into your ears.
      I’ve tried some other ones ( tapered shape)
      but the foam was too fast to get them into your ears correctly before the plugs swell up again.

  3. My guess is that your ear parts probably aren’t the right size to resonate at that frequency, so the sound doesn’t hurt them.

  4. Impressive! i’ve seen acoustic levitation before, but not with the sound waves perpendicular to gravity! very very cool!

  5. Use it to levitate particles and illuminate them to make a 3d hologram or whatever it would be called. but put it on an R2D2 and play back leia’s message.

  6. smaller standing waves…..more particles, a projector and a camera somewhere and viola…an interactive hologram maybe?

  7. In case anyone is curious about what’s inside those black square ‘transducer array’ thingies:
    [flash]http://www.youtube.com/watch?v=_zE1FprnVVQ[/flash]

  8. I’ve wanted to play around with ultrasonic transducers but everywhere I look they are priced quite high (at least if you plant to buy many of them for an array!).
    Any idea where to get a bunch of them for cheap, preferably without their receiver counterparts?

  9. Interesting experiment. I also was thinking you can perhaps create the right frequency using crystals without using so much power. Maybe even just rubbing a wet rubber tip over the surface would do the trick.

    If anyone tries and it works… gimme a beer.

  10. Could this be down under water ?? if so would the higher viscosity of the liquid allow “levitation” of heaver items. Fluid dynamics applies both to gases and liquids right ??

  11. Imagine the possibilities of this project for transporting small amounts of goods, in say, small tunnels beneath a city, would be awesome to see where this research can be applied.

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