Magic without Spells Bayreuth researchers control levitating objects with acoustic waves

University of Bayreuth, Press release No. 150/2018, 4 December 2018 Controlling the very existence of objects by computer, dubbed “Ultimate Display”, is a vision which has fascinated IT research for more than 50 years. But only now does this goal seem to be within reach. At the University of Bayreuth, Prof. Dr. Jörg Müller and his team are working on a process, by which the spatial position of tiny particles can be controlled with high precision. Now they have presented their newest development at a conference in Tokyo: the LeviCursor, which allows small objects to be moved around the room at the pointing of a fingertip, without them being touched, as if by magic.

Levitating plastic bead, held in a field of ultrasonic waves created by opposing transducers. Photo: Viktorija Paneva. This interactive system developed by Bayreuth researchers, which seemingly does magic, works on ultrasonic waves. Two horizontal boards, positioned one over the other at a distance of approximately 20 centimetres, support arrays of closely arranged loudspeakers (transducers). These produce ultrasonic waves from above and below, meaning that particles located in the space between the two boards are subjected to ultrasound emanating from opposite directions. Such objects, for example tiny plastic beads, can be made to float in mid-air under these circumstances. If the phases of the acoustic waves in this ultrasonic space are modified even slightly, it is possible to put these beads into motion. The LeviCursor makes use of this phenomenon to accurately control the movement of the beads. For this purpose and optical marker (pointer) is utilized, worn on one fingertip. By moving within the ultrasonic space, the pointer alters the three-dimensional field of ultrasound waves containing one of these plastic beads or some other object. Prof. Jörg Müller’s team has managed to enable the fine-tuning of the ultrasonic waves using the pointer, to the extent that a particle can be moved in all three dimensions parallel to the fingertip without there being any direct physical contact. The LeviCursor thus boasts three key characteristics: The particles trace their three-dimensional movements almost simultaneously with the movements of the fingertip, without any obvious time lag. The movement happens not as a series of small steps but continuously, just like the movements of the fingertip. Furthermore, high speeds can be achieved, of up to 80 centimetres per second.

Viktorija Paneva presents the LeviCursor at the ACM conference in Tokyo. Photo: Myroslav Bachynskyi. Dr. Myroslav Bachynskyi and Viktorija Paneva, researchers at the Serious Games Chair, recently presented this system at an international IT-Conference in Tokyo, ACM International Conference on Interactive Surfaces and Spaces. “Visitors from the scientific community were very impressed with how far we have already brought forward the physical fundamentals of the ultrasound-controlled levitation of objects. Our aim is to further refine this technology over the next few years. In particular, we are seeking to achieve even greater speeds and acceleration, and to create whole virtual objects out of levitating particles”, says Viktorija Paneva. Prof. Dr. Jörg Müller, head of the Bayreuth research team, looks into the future: “We can’t really foresee all the possible applications of this technology today. But let’s imagine one day being able to precisely control the very fast movement of many, extremely small particles down at the micron level: In that case larger objects composed out of these particles could transform into other objects in the blink of an eye. In this way, for example, unimaginable surprise effects could be achieved in films or theatre performances.”