Levitating Particle Displays with Interactive Voxels

Levitating objects can be used as the primitives in a new type of display. We present levitating particle displays and show how research into object levitation is enabling a new way of presenting and interacting with information. We identify novel properties of levitating particle displays and give examples of the interaction techniques and applications they allow. We then discuss design challenges for these displays, potential solutions, and promising areas for future research

Levitate: Interaction with Floating Particle Displays

This demonstration showcases the current state of the art for the levitating particle display from the Levitate Project. In this demonstration, we show a new type of display consisting of floating voxels, small levitating particles that can be positioned and moved independently in 3D space. Phased ultrasound arrays are used to acoustically levitate the particles. Users can interact directly with each particle using pointing gestures. This allows users to walk-up and interact without any user instrumentation, creating an exciting opportunity to deploy these tangible displays in public spaces in the future. This demonstration explores the design potential of floating voxels and how these may be used to create new types of user interfaces

Pervasive Displays Research: What's Next?

Reports on the 7th ACM International Symposium on Pervasive Displays that took place from June 6-8 in Munich, Germany

Avoiding Collisions when Interacting with Levitating Particle Displays

Levitating particle displays are an emerging technology where content is composed of physical pixels. Unlike digital displays, manipulating the content is not straightforward because physical constraints affect the placement and movement of each particle: dragging a particle may cause it to collide with others along its movement path. We describe initial work into four new interaction techniques that allow users to avoid collisions when directly manipulating display content. Techniques such as these are required for interactive levitating displays to be practical when scaled up to large sizes

Enhancing Physical Objects with Actuated Levitating Particles

We describe a novel display concept where levitating particles are used to add a dynamic display element to static physical objects. The particles are actuated using ultrasound, for expressive output without mechanical constraints. We explore novel ways of using particles to add dynamic output to other objects, for new interactive experiences. We also discuss the practical challenges of combining these. This work shows how the unique capabilities of levitation can create novel displays by enhancing another form of media

TipTrap: A Co-located Direct Manipulation Technique for Acoustically Levitated Content

Acoustic levitation has emerged as a promising approach for mid-air displays, by using multiple levitated particles as 3D voxels, cloth and thread props, or high-speed tracer particles, under the promise of creating 3D displays that users can see, hear and feel with their bare eyes, ears and hands. However, interaction with this mid-air content always occurred at a distance, since external objects in the display volume (e.g. user's hands) can disturb the acoustic fields and make the particles fall. This paper proposes TipTrap, a co-located direct manipulation technique for acoustically levitated particles. TipTrap leverages the reflection of ultrasound on the users' skin and employs a closed-loop system to create functional acoustic traps 2.1 mm below the fingertips, and addresses its 3 basic stages: selection, manipulation and deselection. We use Finite-Differences Time Domain (FDTD) simulations to explain the principles enabling TipTrap, and explore how finger reflections and user strategies influence the quality of the traps (e.g. approaching direction, orientation and tracking errors), and use these results to design our technique. We then implement the technique, characterizing its performance with a robotic hand setup and finish with an exploration of the ability of TipTrap to manipulate different types of levitated content

High-speed acoustic holography with arbitrary scattering objects

Recent advances in high-speed acoustic holography have enabled levitation-based volumetric displays with tactile and audio sensations. However, current approaches do not compute sound scattering of objects’ surfaces; thus, any physical object inside can distort the sound field. Here, we present a fast computational technique that allows high-speed multipoint levitation even with arbitrary sound-scattering surfaces and demonstrate a volumetric display that works in the presence of any physical object. Our technique has a two-step scattering model and a simplified levitation solver, which together can achieve more than 10,000 updates per second to create volumetric images above and below static sound-scattering objects. The model estimates transducer contributions in real time by reformulating the boundary element method for acoustic holography, and the solver creates multiple levitation traps. We explain how our technique achieves its speed with minimum loss in the trap quality and illustrate how it brings digital and physical content together by demonstrating mixed-reality interactive applications