Lapillus bug: Creature-like behaving particles based on interactive mid-air acoustic manipulation

Modern technology development has made the border between life and matter more ambiguous. Studies that find creature-like behavior from inorganic materials are carried out in the field of art and entertainment. On the other hand, it is an important issue to manipulate objects without implanting any actuators directly inside. In this research, we aim to extract and express creature-like behavior from inanimate objects by usage of external force. By generating a standing wave with focused ultrasound, a phenomenon known as acoustic levitation enables a physical particle to float in mid-air. The particle is trapped in the ultrasonic focal point and follows its position. We have developed a system so that users can interact with the floating particle that looks and behaves as though it is a small hovering bug. We have received many reactions and opinions from attendees at exhibitions. In this paper, we describe the system overview, concept, design, implementation, and feedback from the exhibitions.