Stick&Slip - Altering Fingerpad Friction via Liquid Coatings
September 2022 - June 2023
Published: CHI '24; Also showcased at the 2024 IEEE Haptics Symposium
Authors: Alex Mazursky, Jacob Serfaty, Pedro Lopes
Affiliation: UChicago Human-Computer Integration Lab
Video Showcase
2 Full Video _compressed.mp4Abstract
We present Stick&Slip, a novel approach that alters friction between the fingerpad & surfaces by depositing liquid droplets that coat the fingerpad. The liquid coating modifies the finger’s coefficient of friction, allowing users to feel surfaces up to ±60% more slippery or sticky. We selected our fluids to rapidly evaporate so that the surface returns to its original friction. Unlike traditional friction-feedback, such as electroadhesion or vibration, our approach: (1) alters friction on a wide range of surfaces and geometries, making it possible to modulate nearly any non-absorbent surface; (2) scales to many objects without requiring instrumenting the target surfaces (e.g., with conductive electrode coatings or vibromotors); and (3) both in/decreases friction via a single device. We identified nine liquids and characterized their practicality by measuring evaporation rates, etc. To illustrate the applicability of our approach, we demonstrate how it enables friction in virtual/mixed-reality or, even, while using everyday objects/tools.
What did I contribute?
Designed and programmed an Augmented Reality demo for the Microsoft Hololens 2 using the Unity game engine
Created an alignment system that allows administrators to align the game with a real-world surface before starting the game
Implemented a smart tracking system that allows a virtual car to smoothly drive alongside the user's finger on a 2D surface
Modified this tracking system to support driving along certain predefined 3D surfaces such as flat and curved ramps
Programmed a Mario-kart-inspired racing management system that defines races through predefined checkpoints and spawns in new regions whenever a checkpoint is reached
Programmed haptic detection zones and integrated them into the racing system to spawn haptic zones when the car crosses key environmental features
Organized and ran a 12-person user study to evaluate the effectiveness of the haptic effects when playing the racing game
Worked with Alex to design an improved communication API for the fluid-dispensing device