Publications

2025

1. 

   GhostObjects: Instructing Robots by Manipulating Spatially Aligned Virtual Twins in Augmented Reality

   Lauren W. Wang, and Parastoo Abtahi

   In Adjunct Proceedings of the 38th Annual ACM Symposium on User Interface Software and Technology, 2025

   Abs Link Video

   Robots are increasingly capable of autonomous operations, yet human interaction remains essential for issuing personalized instructions. Instead of directly controlling robots through Programming by Demonstration (PbD) or teleoperation, we propose giving instructions by interacting with GhostObjects—world-aligned, life-size virtual twins of physical objects—in augmented reality (AR). By direct manipulation of GhostObjects, users can precisely specify physical goals and spatial parameters, with features including real-world lasso selection of multiple objects and snapping back to default positions, enabling tasks beyond simple pick-and-place.

2024

1. 

   ECSkin: Tessellating Electrochromic Films for Reconfigurable On-skin Displays

   Pin-Sung Ku, Shuwen Jiang*, Wei-Hsin Wang*, and 1 more author

   Proc. ACM Interact. Mob. Wearable Ubiquitous Technol., May 2024

   Abs Link

   Emerging electrochromic (EC) materials have advanced the frontier of thin-film, low-power, and non-emissive display technologies. While suitable for wearable or textile-based applications, current EC display systems are manufactured in fixed, pre-designed patterns that hinder the potential of reconfigurable display technologies desired by on-skin interactions. To realize the customizable and scalable EC display for skin wear, this paper introduces ECSkin, a construction toolkit composed of modular EC films. Our approach enables reconfigurable designs that display customized patterns by arranging combinations of premade EC modules. An ECSkin device can pixelate patterns and expand the display area through tessellating congruent modules. We present the fabrication of flexible EC display modules with accessible materials and tools. We performed technical evaluations to characterize the electrochromic performance and conducted user evaluations to verify the toolkit’s usability and feasibility. Two example applications demonstrate the adaptiveness of the modular display on different body locations and user scenarios.

2023

1. 

   AirCharge: Amplifying Ungrounded Impact Force by Accumulating Air Propulsion Momentum

   Po-Yu Chen*, Ching-Yi Tsai*, Wei-Hsin Wang*, and 5 more authors

   In Proceedings of the 36th Annual ACM Symposium on User Interface Software and Technology, May 2023

   Abs Link Video

   Impact events, which generate directional forces with extremely short impulse durations and large force magnitudes, are prevalent in both virtual reality (VR) games and real-world experiences. However, despite recent advancement in ungrounded force feedback technologies, such as air jet propulsion and propellers, these technologies remain 5-100x weaker and 10-500x slower compared to real-world impact events. For instance, they can only achieve 4N with a minimal duration of 50-500ms compared to the 20-400N forces generated within 1-5ms for baseball, ping-pong, drumming, and tennis. To overcome these limitations, we present AirCharge, a novel haptic device that accumulates air propulsion momentum to generate instantaneous, directional impact forces. By mounting compressed air jets on rotating swingarms, AirCharge can amplify impact force magnitude by more than 10x while matching real-world impulse duration of 3ms. To support high-frequency impacts, we explored and evaluated a series of device designs, culminating in a novel reciprocating dual-swingarm design that leverages a reversing bevel gearbox to eliminate gyro effects and to achieve impact feedback of up to 10Hz. User experience evaluation (n = 16) showed that AirCharge significantly enhanced realism and is preferred by participants compared to air jets without the charging mechanism.

2022

1. 

   UltraBat: An Interactive 3D Side-Scrolling Game Using Ultrasound Levitation

   Wei-Hsin Wang, Hong-En Chen, and Mike Y. Chen

   In Adjunct Proceedings of the 35th Annual ACM Symposium on User Interface Software and Technology, May 2022

   Abs Link Video

   We present UltraBat, an interactive 3D side-scrolling game inspired by Flappy Bird, in which the game character, a bat, is physically levitated in mid-air using ultrasound. Players aim to navigate the bat through a stalagmite tunnel that scrolls to one side as the bat travels, which is implemented using a pin-array display to create a shape-changing passage.

... and more to come!