Vibrations in touch screens are an accepted part of everyday life for most of us. But what if those vibrations could do more? While many advanced haptic devices are under development, touchscreens are one of the most readily available platforms. However, the haptics available in mobile touchscreens can often be underwhelming, carrying frustrating limitations. We decided to leverage a leap forward in vibration-based haptics, Apple's new CoreHaptics API, and investigate its potential for a multi-finger vibration experience. We conducted a perceptual user study that investigates multi-finger identification and exploration strategies and a laser doppler vibrometry study, uncovering the challenges of developing consistent, high-quality vibration feedback across hardware platforms that vary in actuation principle, screen size, and external attachments. This led us to important recommendations on new ways to utilize these capabilities.

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This work is supported by the National Science Foundation under Grant Nos. 1644538 and 1845490. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.