Sabrina A. Panëels

What's around me? Multi-actuator haptic feedback on the wrist

We present the design, implementation and evaluation of a novel wrist-based vibrotactile multi-actuator bracelet, based on a coplanar circular configuration of actuators, for the provision of intuitive and informative haptic feedback for navigation tasks. A two-phase evaluation was conducted in order to assess the perception of the vibrotactile feedback provided by the bracelet and in particular, the ability of users to discriminate a range of vibrotactile patterns. First, a pilot study designed to test perception of different kinds of pattern was conducted with the aim of both refining the pattern design and aiding the choice of a discriminable set of patterns. Second, an identification experiment with the previously chosen set of patterns was conducted with the aim of conveying navigational directions and points of interest to the user. Results highlighted the difficulties in identifying the number of activated actuators as well as their position on the wrist, which subsequently had an impact on the pattern recognition. It was found that one-way horizontal and vertical movements were difficult to perceive correctly, however, less specific movements such as circular or alternating lateral movements and rhythm proved to be suitable parameters for the perception of patterns as long as the patterns were not too similar in design.

Listen to it yourself!: evaluating usability of what's around me? for the blind

Although multiple GPS-based navigation applications exist for the visually impaired, these are typically poorly suited for in-situ exploration, require cumbersome hardware, lack support for widely accessible geographic databases, or do not take advantage of advanced functionality such as spatialized audio rendering. These shortcomings led to our development of a novel spatial awareness application that leverages the capabilities of a smartphone coupled with worldwide geographic databases and spatialized audio rendering to convey surrounding points of interest. This paper describes the usability evaluation of our system through a task-based study and a longer-term deployment, each conducted with six blind users in real settings. The findings highlight the importance of testing in ecologically valid contexts over sufficient periods to face real-world challenges, including balancing quality versus quantity for audio information, overcoming limitations imposed by sensor accuracy and quality of database information, and paying appropriate design attention to physical interaction with the device.

Strike a Pose: Directional Cueing on the Wrist and the Effect of Orientation

Many wearable haptic devices have been developed for providing passive directional cues, in the form of belts or back displays but these systems have so far failed to make an impact in the public domain. One other potential solution is a light, discrete and aesthetically acceptable vibrotactile bracelet. However, contrary to these other systems, the wrist is subject to rotations, therefore a controversial locus for vibrotactile feedback in a navigational context. This paper presents a set of experiments aimed at both determining the basic feasibility of using this kind of bracelet and to examine to what extent the orientation of the users wrist affects their perception of directional cues both in static and mobile conditions. It was found that changes in orientation have little negative effect overall, distraction being more of a concern.

A vibrotactile wristband to help older pedestrians make safer street-crossing decisions

INTRODUCTION Older pedestrians are overrepresented in fatal accidents. Studies consistently show gap-acceptance difficulties, especially in complex traffic situations such as two-way streets and when vehicles approached rapidly. In this context, the present research was aimed at assessing the effectiveness of a vibrotactile device and study older pedestrians behavior when wearing the wristband designed to help them make safer street-crossing decisions. METHOD Twenty younger-old participants (age 60-69), 20 older-old participants (age 70-80) and 17 younger adults (age 20-45) carried out a street-crossing task in a simulated two-way traffic environment with and without a vibrotactile wristband delivering warning messages. RESULTS The percentage of decisions that led to collisions with approaching cars decreased significantly when participants wore the wristband. Benefits tended to be greater particularly among very old women, with fewer collisions in the far lane and when vehicles approached rapidly when they wore the wristband. But collisions did not fall to zero, and responses that were in accordance with the wristband advice went up to only 51.6% on average, for all participants. The wristband was nevertheless considered useful and easy to use by all participants. Moreover, behavioral intentions to buy and use such a device in the future were greater in both groups of older participants, but not among the younger adults. PRACTICAL APPLICATIONS This haptic device was able to partly compensate for some age-related gap-acceptance difficulties and reduce street-crossing risks for all users. These findings could be fruitfully applied to the design of devices allowing communication between vehicles, infrastructures, and pedestrians.

smiles, kids, happy songs!: how to collect metaphors with older adults

In the context of an ageing society, vibrotactile wearable devices can open up new avenues for assisting older adults in their daily lives. They can provide information and yet free the hands, ears and eyes, which can be crucial to safety. However, designing intuitive informational vibrotactile messages for and with the older adults has seldom been investigated. This paper describes an initial study involving older adults in the design of vibrotactile messages for a pedestrian navigation application. The design is based on metaphors or everyday analogies in an attempt to strengthen the link between the pattern and its associated meaning. The study presents the method to collect these metaphors, focusing on the difficulties encountered with such an abstract task and the steps taken to adapt it to the audience. As a result, a number of metaphors were collected, in line with what matters for older adults (e.g. kids, health).

Localisation of Vibrotactile Stimuli with Spatio-Temporal Inverse Filtering

A number of researchers and companies have investigated methods to improve touchscreen interaction through actuators providing vibrotactile stimuli. Wave propagation enables remote actuation but makes such stimuli perceivable all over the surface. In this paper, we report the use of an array of actuators combined with a spatio-temporal inverse filter to produce independent vibrotactile feedback at different positions on a surface. A experimental evaluation showed that this setup successfully corrects for distortion, reverberation and cross talk between piezoelectric actuators glued to a glass surface providing 300 Hz burst vibrations. A user study conducted with 10 participants demonstrated that this filtering not only improved the user’s discrimination but also required less concentration when compared to a method without such filtering.

ViSecure: A Haptic Gesture Authentication System

Secure authentication is an important part of our everyday interaction with computers. While the traditional password or pin-code still dominates this area, there has been a move towards more novel forms of authentication including gestures and biometric finger printing. In this paper we present the use of a wearable device with localized vibration as a method for authentication that is both secure and discreet and which removes the need to memorise pin codes or passwords. An initial user study found that participants were open to this kind of device and interaction.

INTACT: Instant Interaction with 3D Printed Objects

The INTACT platform enables the instant addition of interactivity to any 3D printed object, with the aim of enriching and enhancing the interaction design process. This is achieved by eliminating the need to incorporate potentially obstructive sensor technologies. Using a system of force sensing combined with a digital model of the object the system is capable of detecting a single touch, its position and the corresponding force of that touch anywhere on the object.

Methods for User Involvement in the Design of Augmented Reality Systems for Engineering Education

The paper presents a number of user involvement methods which can be used in the design of Augmented Reality (AR) systems for engineering education. One of the characteristics of these technologies is that future users do not always have a thorough knowledge of AR and its applications in engineering education. Furthermore, the technology is in search of applications, and there are few existing HCI guidelines for AR interfaces. In this sense, the design and usability evaluation of these systems are real challenges. We present methods which are suitable in this context (e.g. scenarios, field studies, activity analysis, and formative evaluations of prototypes). We also discuss their advantages and limitations when designing AR systems for engineering education from a user-centred perspective.