Material Experience Design | Yasuaki Kakehi Laboratory, The University of Tokyo

Yasuaki Kakehi Laboratory


We present an approach to realize the levitation of a small object with an embedded electronic circuit. Luciola is a light-emiting particle with a diameter of 3.5mm and a weight of 16.2mg moving in mid-air in a 10.4cm x 10.4cm x 5.4cm space through acoustic levitation using two 40-kHz 17 x 17 ultrasonic transducer arrays placed face-to-face at a distance of 20cm and wirelessly powered by 12.3-MHz resonant inductive coupling. Te novelty of this paper is the acoustically levitated electronic object by the combined application of ultrasonic levitation and wireless powering to the levitated electronic object.

A new shape of the levitated object and a new placement of the receiver coil to simultaneously realize acoustic levitation and wireless powering are proposed, achieving a stable wireless powering to a rotating levitated object at the bottom of an acoustic potential. To enable the levitation of a particle, a custom IC chip is essential in reducing the size and weight of the particle. In the design of the custom IC chip, a new voltage detector circuit enabling an accurate voltage detection and a correct output during the start-up is proposed to achieve an intermittent lighting of the LED to increase the maximum distance between the transmiter and the receiver coil. Luciola is applied to a self-luminous pixel in a mid-air display and drawings of characters in mid-air are demonstrated.

Yuki Uno, Hao Qiu, Toru Sai, Shunta Iguchi, Yota Mizutani, Takayuki Hoshi, Yoshihiro Kawahara, Yasuaki Kakehi, and Makoto Takamiya. 2018. Luciola: A Millimeter-Scale Light-Emitting Particle Moving in Mid-Air Based On Acoustic Levitation and Wireless Powering. Proc. ACM Interact. Mob. Wearable Ubiquitous Technol. 1, 4, Article 166 (January 2018), 17 pages. DOI:

Acknowledgement: JST Kawahara ERATO Universal Information Network Project(万有情報網プロジェクト)