Pixie Dust

Graphics Generated by Levitated and Animated Objects in a Computational Acoustic-Potential Field

This novel graphics system is based on expansion of 3D-acoustic-manipulation technology. In the conventional study of acoustic levitation, small objects are trapped in the acoustic beams of standing waves. Here, this method is expanded by changing the distribution of the acoustic-potential field (APF), which generates the graphics using levitated small objects. The system makes available many expressions, such as expression by materials and nondigital appearance.

In the current system, multiple particles are levitated together at 4.25-mm intervals. The spatial resolution of the position is 0.5 mm. Particles move at up to 72 cm/s. The allowable density of the material can be up to 7 g/cm^3. This study used three options for APF: a 2D grid, high-speed movement, and a combination with motion capture. They are used to realize floating-screen or midair raster graphics, midair vector graphics, and interaction with levitated objects.

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4 Responses:

  1. mattyj says:

    I'll always remember where I was when I found out magic is real.

  2. Ru says:

    Previously? I eagerly await videos of levitation of droplets of burning napalm...

    • jwz says:

      "I looked across the square and watched a tourist burning in blue fire. They had gasoline that burned in all colors by then... Just look at them out there all those little figures dissolving in light. Rather like fairy land isn't it, except for the smell of gasoline and burning flesh."

  3. Pflanze says:

    Does anyone have a real explanation on what leads to the 'trapping'? I know what a standing wave is, and that there are zones with moving air at constant pressure and zones with still air at changing pressure (and zones in-between with a mix of both); now how does this lead to a trapping, especially as the zones seem to be vertically oriented here and hence the nodes that they claim would trap the particles would seem to prevent them from moving horizontally, but not from moving down vertically.

    There must be something going on that's not well visible in the dry ice demonstration, like (deliberate) 'imperfections' in the vertical standing wave. And even then, I don't see why a particle would be trapped in say a zone of still (but pressure-changing) air unless the in-moving phase at the edge of the zone is exerting a different amount of force on the particle than the out-moving phase, which means there needs to be some kind of non-linearity going on?

    Well, they mention that they turn one speaker set off or lower. It seems more likely that the particles are trapped between the line of those speakers and those below (than those above). Now, perhaps the volume of the sound is high enough that when the air rushes towards a high-pressurization zone, the pressure rises higher than it lowers during the low-pressurization phase (I'd have to think this through carefully to see whether that should really happen, involving the momentum of the air). This would mean that the periodic downward suction would be less than the upward pressure, hence, levitation. Am I on the right track so far? (If so, the explanation in the video is really pathetic as they claim it is because the particles are "trapped in nodes of the standing wave", whereas in fact they are lifted by the difference of the volume of the standing waves.)