RealPen: Providing Realism in Handwriting Tasks on Touch Surfaces using Auditory-Tactile Feedback

TL;DR

RealPen is an augmented stylus that enhances touch screen writing by recreating the tactile and auditory sensations of writing on paper, aiming to improve user engagement and realism.

Contribution

This work introduces a novel algorithm for generating realistic tactile and sound feedback based on friction oscillation analysis, improving the realism of digital handwriting experiences.

Findings

RealPen produces perceptually realistic tactile feedback.

Users preferred feedback that mimics real writing tools.

The system effectively aligns sound with writing dynamics.

Abstract

We present RealPen, an augmented stylus for capacitive tablet screens that recreates the physical sensation of writing on paper with a pencil, ball-point pen or marker pen. The aim is to create a more engaging experience when writing on touch surfaces, such as screens of tablet computers. This is achieved by re-generating the friction-induced oscillation and sound of a real writing tool in contact with paper. To generate realistic tactile feedback, our algorithm analyses the frequency spectrum of the friction oscillation generated when writing with traditional tools, extracts principal frequencies, and uses the actuator's frequency response profile for an adjustment weighting function. We enhance the realism by providing the sound feedback aligned with the writing pressure and speed. Furthermore, we investigated the effects of superposition and fluctuation of several frequencies on human tactile perception, evaluated the performance of RealPen, and characterized users' perception and preference of each feedback type.