Midair Balloon Interface: A Soft and Lightweight Midair Object for Proximate Interactions

This paper introduces a midair balloon interface, a fast and soft interactive object in mid-air. Our approach tackles the trade-off between safety and speed by controlling a soft helium-filled balloon with external actuators and sensors. We developed a prototype system that uses airborne ultrasound phased arrays to propel a balloon and high-speed stereo cameras to track its motion. This configuration realizes both a high thrust/weight ratio and such a soft body that is safe-to-collide. We describe a sight-based interaction and a touch-based interaction that leverage the safety and speed of a midair balloon interface. A sight-based interaction allows the user to keep the object inside her/his view within reach by controlling a balloon to follow the direction of the user’s face. A touch-based interaction allows the user to manipulate the object directly with his/her hand, issue a command by moving his/her finger on the surface, and receive vibrotactile feedback produced by vibrating the balloon with amplitude-modulated ultrasound. We describe the implementation and evaluation of the prototype and explore the application scenarios.