Mid-air ultrasound technology offers new design opportunities for contactless tactile patterns (i.e., Tactons) in user applications. Yet, few guidelines exist for making ultrasound Tactons easy to distinguish for users. In this paper, we investigated the distinguishability of temporal parameters of ultrasound Tactons in five studies (n=72 participants). Study 1 established the discrimination thresholds for amplitude-modulated (AM) frequencies. In Studies 2–5, we investigated distinguishable ultrasound Tactons by creating four Tacton sets based on mechanical vibrations in the literature and collected similarity ratings for the ultrasound Tactons. We identified a subset of temporal parameters, such as rhythm and low envelope frequency, that could create distinguishable ultrasound Tactons. Also, a strong correlation (mean Spearman’s ρ =0.75) existed between similarity ratings for ultrasound Tactons and similarities of mechanical Tactons from the literature, suggesting vibrotactile designers can transfer their knowledge to ultrasound design. We present design guidelines and future directions for creating distinguishable mid-air ultrasound Tactons.

High-fidelity vibration actuators in recent mobile phones allow designers to crowdsource user evaluation of vibrotactile (VT) Tactons. Yet, little work has examined whether online crowdsourcing platforms can provide comparable results to lab studies. To address this question, we conducted two studies with iOS devices in the lab and crowdsourced settings. In Study I, 40 users provided pairwise similarity ratings for 12 VT Tactons that varied in their parameters (e.g., duration). In Study II, 40 new users rated pairwise similarities for 14 Tactons representing different metaphors (e.g., heartbeat). They also rated the Tactons’ match to the metaphors. In both studies, the resulting similarities and perceptual spaces strongly correlated in the lab and crowdsourced settings. Furthermore, 60% of the metaphor ratings were statistically equivalent in the two settings. We discuss the results and outline directions for future work on haptic crowdsourcing.

Perceptual dissimilarities, requiring high-cost user ratings, have contributed to designing well-distinguishable vibrations for associated meaning delivery. Appropriate metrics can reduce the cost, but known metrics in vibration similarity/dissimilarity could not predict them robustly. We propose a physiology-based model (PM) that predicts the perceptual dissimilarities of a given vibration set via two parallel processes: Neural Coding (NC), mimicking the neural signal transfer, and One-dimensional Convolution (OC), capturing rhythmic features. Eight parameters were trained using six datasets published in the literature to maximize Spearman’s Rank Correlation. We validated PM and six metrics of RMSE, DTW, Spectral/Temporal Matchings, ST-SIM, and SPQI in twelve datasets: six trained and six untrained datasets including measured accelerations. In all validations, PM’s predictions showed robust correlations with user data and similar structures in perceptual spaces. Other baseline metrics showed better fit in specific datasets, but none of them robustly showed correlations and similar perceptual spaces over twelve datasets.

Creating haptic experiences often entails inventing, modifying, or selecting specialized hardware. However, interaction designers are rarely engineers, and 30 years of haptic inventions are buried in a fragmented literature that describes devices mechanically rather than by potential purpose. We conceived of Haptipedia to unlock this trove of examples: Haptipedia presents a device corpus for exploration through metadata that matter to both device and interaction designers. It is a taxonomy of device attributes that go beyond physical description to capture potential utility, applied to a growing database of 105 grounded force-feedback devices, and accessed through a public visualization that links utility to morphology. Haptipedia's design was driven by both systematic review of the haptic device literature and rich input from diverse haptic designers. We describe Haptipedia's reception (including hopes it will redefine device reporting standards) and our plans for its sustainability through community participation.

Interaction on the surface usually limited in mechanical movement and does not have surface texture, which results in a lack of haptic feedback. Various techniques have been introduced to supplement this limitation. The main objective of this tutorial is to let the ISS community experience those technologies in hand. By its nature, the haptic interface is hardly explainable with a document, video, and audio. We provide a unique opportunity for the ISS community to feel and experience the wide range of haptic techniques on the surface. In specific, the tutorial will cover the following topics. 1) haptic feedback on a small mobile device 2) Texture rendering on a larger surface 3) An illusion of compliance on a rigid device 4) Pin-array display for information transfer.

A phantom sensation refers to an illusory tactile sensation perceived midway between multiple distant stimulations on the skin. Phantom sensations have been used intensively in tactile interfaces owing to their simplicity and effectiveness. Despite that, the perceptual performance of phantom sensations is not completely understood, especially for 2D cases. This work is concerned with 2D stationary phantom sensations and their fundamental value as a means for information display. In User Study 1, we quantified the information transmission capacity using an absolute identification task of 2D phantom sensations. In User Study 2, we probed the distributions of the actual perceived positions of 2D phantom sensations. The investigations included both types of phantom sensations-within and out of the body. Our results provide general guidelines as to leveraging 2D phantom sensations in the design of spatial tactile display.

Amplitude-modulated vibrotactile stimuli have been broadly used for tactile perception and rendering research. However, understandings of the perceptual relations between amplitude-modulated vibrations are not comprehensive yet. In this paper, we present a perceptual analysis on the identifying characteristics of amplitude-modulated vibrations and their perceptual relations. We estimated the perceptual dissimilarities among one carrier and seven amplitude-modulated sinusoidal vibrations (150-Hz carrier frequency; seven modulation frequencies in 1-80 Hz) in a psychophysical experiment. The dissimilarity scores were inspected using multi-dimensional scaling to obtain an appropriate perceptual space. The optimal perceptual space was two-dimensional, where the vibration points exhibited a circular formation. The analysis showed that the pulse-like low-frequency sensation of an amplitude-modulated vibration increased for very low modulation frequencies (1-10 Hz), then decreased for higher modulation frequencies (10-80 Hz), and eventually converged to the smooth vibrational sensation of the 150-Hz carrier signal. It also suggested that the envelope waveform is primary information for the discrimination of amplitude-modulated signals, instead of their spectral energy distributions. These findings can contribute to the design of perceptually salient and distinctive vibrotactile signals using amplitude modulation.

In this paper, we present the design of a large number (72) of tactile stimuli for the confirmation feedback of virtual button presses on the mobile device touchscreen. Two industry standard variable-reluctance actuators (enhanced voice-coil actuators with added mass for stronger output) were used in the study. The design parameters of an input were amplitude, duration, carrier signal, envelope function, and actuator. Eighteen participants evaluated the modeled patterns with the criteria of similarity to physical buttons and user preference. An adjective rating task was also accompanied to assess the subjective quality of the designed tactile effects. Experimental results unveiled several important guidelines for designing realistic and favorable button-click tactile feedback. The findings of this paper have implications for improving the usability of user interface components displayed on a touchscreen by means of haptic feedback.