Two-Gimbal PAT: An artistic installation combining mechanical and acoustic rotation of levitated content

Interactive applications using ultrasonic phased arrays of transducers (PATs) provide novel opportunities to create 3D displays. They show visual content using levitated particles such as polystyrene beads, thread or fabric, that dynamically change to render volumetric shapes in mid-air. Typically, this technology uses fixed arrays of transducers (e.g., two boards vertically or horizontally aligned) to display interactive content. That is, a fixed system of reference (SoR), defined by the levitation device, and dynamic mid-air content. This demo proposes a novel setup, featuring a dynamic-SoR for the device with the dynamic mid-air content. We do this by combining a PAT-based levitation device mounted onto a two-gimbal mechanism, resulting into a device with a dynamic coordinate system for volumetric animations. We describe our setup and demonstration, which aims to create an intriguing experience, where both the content and the device itself can freely move in 3D space, with the aim of challenging the user's expectations about the content displayed or even the principles enabling it.