The promise of on-body interactions has led to widespread development of wearable displays. They manifest themselves in highly variable shapes and form, and are realized using technologies with fundamentally different properties. Through an extensive survey of the field of wearable displays, we characterize existing systems based on key qualities of displays and wearables, such as location on the body, intended viewers or audience, and the information density of rendered content. We present the results of this analysis in an open, web-based interactive design space that supports exploration and refinement along various parameters. The design space, which currently encapsulates 129 cases of wearable displays, aims to inform researchers and practitioners on existing solutions and designs, and enable the identification of gaps and opportunities for novel research and applications. Further, it seeks to provide them with a thinking tool to deliberate on how the displayed content should be adapted based on key design parameters. Through this work, we aim to facilitate progress in wearable displays, informed by existing solutions, by providing researchers with an interactive platform for discovery and reflection.

Detecting tangibles on capacitive touchscreen has seen vast attention over the past decade. Current state of the art allows a capacitive touchscreen to detect and identify a number of tangibles based on a unique footprint of interconnected conductive elements on the base of the tangible. In most cases, this conductive material is either metal or some carbon-based conductor, possibly integrated into a 3D-printing process. The choice of conductive material is, however, not limited to these technical elements. In this paper, we showcase how the concept of tangible detection on capacitive touchscreens can be transferred to pastry, creating an ephemeral, edible user interface. The detection and identification of specific pieces of pastry open applications in the area of entertainment, but also food safety.

Listening to music while being on the move is common in our headphone society. However, if we want assistance in navigation from our smartphone, existing approaches either demand exclusive playback through the headphones or impact the listening experience of the music. We present a field evaluation of Attracktion, a spatial audio navigation system that leverages the access to single stems in a multi-track recording to minimize the impact on the listening experience. We compared Attracktion against current turn-by-turn navigation instructions in a field-study with 22 users and found that users perceived acoustic overlays with additional navigation information to have no impact on the listening experience. In terms of path efficiency, errors, and mental workload, Attracktion is on par with spoken turn-by-turn navigation instructions, and users liked it for the aspect of serendipity.

Laser cutters are 2D tools, but their speed and compatibility with a variety of affordable materials also makes them a frequent choice to create 3D objects. We propose CutCAD, a tool to easily construct simple 3D objects from 2D faces, inspired by the process of paper modeling and magnetic construction kits. The user creates her 3D model by drawing or loading existing 2D shapes, and connecting their edges in the software. CutCAD then automatically resolves the resulting constraints, and folds the faces up into a 3D model that is previewed live. CutCAD also automatically creates the required finger joints based on thickness of the material and dihedral angles, for smooth assembly. Cutouts are easy to add by importing their outlines as vector drawings, and placing them onto faces. After the faces have been cut, CutCAD provides assembly instructions. Observations and feedback from using CutCAD show the resulting process to be easier to understand than traditional 3D modelling. CutCAD is open-source, and has been downloaded over 2,000 times.

As humans, we have the natural capability of localizing the origin of sounds. Spatial audio rendering leverages this skill by applying special filters to recorded audio to create the impression that a sound emanates from a certain position in the physical space. A main application for spatial audio on mobile devices is to provide non-visual navigation cues. Current systems require users to either listen to artificial beacon sounds, or the entire audio source (e.g., a song) is repositioned in space, which impacts the listening experience. We present NavigaTone, a system that takes advantage of multi-track recordings and provides directional cues by moving a single track in the auditory space. While minimizing the impact of the navigation component on the listening experience, a user study showed that participants could localize sources as good as with stereo panning while the listening experience was rated to be closer to common music listening.

Wearable toolkits simplify the integration of micro-electronics into fabric. They require basic knowledge about electronics for part interconnections. This technical aspect might be perceived as a barrier. We propose YAWN, a bus-based, modular wearable toolkit that simplifies the interconnection by relying on a pre-fabricated three-wire fabric band. This allows quick reconfiguration, ensures washability, and reduces the number of connection problems.

Choosing a seat for traveling can be a complex evaluation of constraints depending on personal preferences. There are websites that help to choose the best seat in a bus, in a train, or on an airplane. However, these recommendations only consider seat-related factors and not the view from the window. While a scenic view rarely influences the decision for a seat on a plane, it is much more important for train rides and especially for scenic bus tours. Therefore, travel website users often discuss which side offers the best view on a specific trip. We propose an algorithm, which decides on which side of the road the view is the most scenic based on Google Street View images. These results can be used by travelers to choose a seat and by scenic tour providers to balance the scenic views between sides or add options during checkout.

Traditional audio guides in museums and similar spaces typically require the visitor to locate a track number at each exhibit and enter it on a keypad. These guides, however, provide no information on the amount of content available. Current mobile devices provide rich output capabilities, and indoor location tracking technology can simplify the selection of content in modern audio guides. In this paper, we compare the keypad-based interface to a map-based interface with and without automatic localization. Through a field study in a local museum with 84 participants, we found that the usability of all versions is rated high, with the keypad interface coming out ahead. Nevertheless, visitors favored the overview of the map and thumbnails to find the right exhibit, while numbers were considered helpful indicators in the real world. Those who used the self-localizing guide preferred it over manually adjusting the map.

Mobile audio augmented reality systems (MAARS) simulate virtual audio sources in a physical space via headphones. While 20 years ago, these required expensive sensing and rendering equipment, the necessary technology has become widely available. Smartphones have become capable to run high-fidelity spatial audio rendering algorithms, and modern sensors can provide rich data to the rendering process. Combined, these constitute an inexpensive, powerful platform for audio augmented reality.

Mobile audio augmented reality systems (MAARS) provide a new and engaging modality to present information or to create playful experiences. Using special filters, spatial audio rendering creates the impression that the sound of a virtual source emanates from a certain position in the physical space. So far, most of the implementations of such systems rely on head tracking to create a realistic effect, which requires additional hardware. Recent results indicate that the built-in sensors of a smartphone can be used as source for orientation measurement, reducing deployment to a simple app download. AudioScope presents an alternative interaction technique to create such an experience, using the metaphor of pointing a directional microphone at the environment. In an experiment with 20 users, we compared the time to locate a proximate audio source and the perceived presence in the virtual environment. Results show that there is no significant difference between head-orientation measurement and AudioScope regarding accuracy and perceived presence. This means that MAARS, such as audio guides for museums, do not require special hardware but can run on the visitor's smartphones with standard headphones.

Audio augmented reality systems overlay the physical world with a virtual audio space. Today's smartphones provide enough processing power to create the impression of virtual sound sources being located in the real world. To achieve this, information about the user's location and orientation is necessary which requires additional hardware. In a real-world installation, however, we observed that instead of turning their head to localize sounds, users tend to turn their entire body. Therefore, we suggest to simply measure orientation of the user's body - or even just the mobile device she is holding - to generate the spatial audio.

Mobile audio augmented reality systems can be used in a series of applications, e.g., as a navigational aid for visually impaired or as audio guide in museums. The implementation of such systems usually relies on head orientation data, requiring additional hardware in form of a digital compass in the headphones. As an alternative we propose AudioTorch, a system that turns a smartphone into a virtual directional microphone. This metaphor, where users move the device to detect virtual sound sources, allows quick orientation and easy discrimination between proximate sources, even with simplified rendering algorithms. We compare the navigation performance of head orientation measurement to AudioTorch. A lab study with 18 users showed the rate of correctly recognized sources to be significantly higher with AudioTorch than with head-tracking, while task completion times did not differ significantly. The presence in the virtual environment received similar ratings for both conditions.

Although digital media playback and storage have several advantages, many DJs still prefer using vinyl records on turntables due to their direct manipulation and haptic qualities. The physical structure of a traditional vinyl record provides important cues for in-track navigation, such as track length or location of loud and soft passages. Digital vinyl systems use a timecode record to combine the advantages of digital playback with the handling DJs are used to. These records contain a special audio signal that is processed by a computer and mapped to information such as playback speed, direction, and absolute position in a track. However, due to their generic nature, timecode records cannot provide visual information to navigate inside individual tracks. Using top-projection, DiskPlay augments a white timecode record with individual visual cues of the medium, such as cue points or track start and end. In our observational study with four professional DJs, participants valued the co-location of visual feedback with the control vinyl on the turntable.

We present Pinstripe, a textile user interface element for eyes-free, continuous value input on smart garments that uses pinching and rolling a piece of cloth between your fingers. The input granularity can be controlled in a natural way by varying the amount of cloth pinched. Pinstripe input elements physically consist of fields of parallel conductive lines sewn onto the fabric. This way, they can be invisible, and can be included across large areas of a garment. Pinstripe also addresses several problems previously identified in the placement and operation of textile UI elements on smart clothing. Two user studies evaluate ideal placement and orientation of Pinstripe elements on the users' garments as well as acceptance and perceived ease of use of this novel textile input technique.