Crepe: A Mobile Screen Data Collector Using Graph QueryCollecting mobile screen information datasets remains challenging for academic researchers. Commercial organizations often have exclusive access to mobile data, leading to a “data monopoly” that restricts academic research and user transparency. Existing open-source mobile data collection frameworks primarily focus on mobile sensing data rather than screen content. We present Crepe, a no-code Android app that enables researchers to collect information displayed on screen through simple demonstrations of target data. Crepe utilizes a novel Graph Query technique, which augments mobile UI structures to support flexible identification, location, and collection of specific data pieces. The tool emphasizes participants' privacy and agency by providing full transparency over collected data and allowing easy opt-out. We designed and built Crepe for research purposes only and in scenarios where researchers obtain explicit consent from participants. Code for Crepe will be open-sourced to support future academic research data collection.2026YLYuwen Lu et al.University of Notre DameUser Research Methods (Interviews, Surveys, Observation)Computational Methods in HCIResearch Ethics & Open ScienceCHI
Nudging vs. Reflection in Fitness Wearables: Evaluating the Benefits and Drawbacks of Design Strategies for Wellbeing TechnologiesWhile technology is widely recognised as a tool to enhance wellbeing, there is no clear consensus on the best practices for design. Persuasive strategies, such as nudging, are often seen as effective but raise ethical concerns. Reflection-based approaches offer a potential alternative. However, a clear understanding of the balance between these strategies is crucial for designing effective and ethically sound wellbeing technologies. We conducted two studies with a total of n=163 participants comparing nudging and reflection techniques using contrasting prototypes of fitness wearables. We verified that the prototypes represented key nudging and reflection strategies through expert feedback. Our mixed-methods inquiry shows that certain nudging strategies are perceived as more malicious and more likely to provoke rumination, i.e., negative thought cycles, compared to other wellbeing strategies. We contribute insights to inform design decisions for wellbeing technologies, balancing effectiveness with ethical considerations.2026AWAnna Walczak et al.Lodz University of TechnologyFitness Tracking & Physical Activity MonitoringBehavior Change & Reflection TechnologyCHI
InkStack: A Programmable E-Paper Card System for Board GamesPlaying cards have long been a central feature in board games, despite their physical limitations, such as fragility, and repetitive content. Yet, while HCI research increasingly explores augmented board games, interactive playing cards remain underexplored. In this work, we investigate the use of e-paper displays as interactive playing cards. Based on a formative study with eight game designers, we designed and implemented InkStack---a prototype consisting of e-paper cards, a dedicated programmer, and a web application for card customisation. We then evaluated InkStack in a within-subject study with $n = 20$ participants, comparing its use across four board game mechanics against traditional paper cards and a smartphone. Results show that InkStack is preferred for more complex mechanics, whereas paper and smartphones are sufficient for simpler tasks. The findings also highlight how customisation and versatility can enhance gameplay and enable novel forms of interaction.2026JDJulia Dominiak et al.Lodz University of TechnologyDigitalization of Board & Tabletop GamesDesktop 3D Printing & Personal FabricationCustomizable & Personalized ObjectsCHI
The Office Awakens: Building a Mobile Desk for an Adaptive Workspace with RolliDeskOver the past century, office desks have evolved with technological advancements, yet they have largely overlooked individual user preferences and diverse body types. Traditionally, desks remain static objects, forcing users to adapt their workspaces around them. This research explores how mobile desks can offer a more flexible and adaptive solution. We developed RolliDesk, a mobile desk capable of automatically moving within the workspace. Our open-source desk kit enables researchers to make desks mobile using off-the-shelf electronics and 3D printing. In a mixed-methods study (n=21), we compared three desk configurations: manually controlled via a crank, control panel-operated, and automatically adaptive. Participants found the manual desk creepy, while the automatic desk was considered the most useful, particularly for promoting healthier office habits. This paper contributes RolliDesk’s design and practical insights for advancing reconfigurable and adaptive workstations.2025JDJulia Dominiak et al.Shape-Changing Interfaces & Soft Robotic MaterialsMixed Reality WorkspacesKnowledge Worker Tools & WorkflowsDIS
Situated Artifacts Amplify Engagement in Physical ActivityIn the context of rising sedentary lifestyles, this paper investigates the efficacy of "Situated Artifacts" in promoting physical activity. We designed two artifacts that display users' physical activity data within their homes - one physical and one digital. We conducted a 9-week, counterbalanced, within-subject field study with N=24 participants to assess the impact of these artifacts on physical activity, reflection, and motivation. We collected quantitative data on physical activity and administered daily and weekly questionnaires, employing individual Likert items and standardized instruments, as well as conducted interviews post-prototype usage. Our findings indicate that while both artifacts act as reminders for physical activity, the physical artifact was superior in terms of user engagement. The study revealed that this can be attributed to the higher perceived presence and, thereby, enhanced social interaction, which acts as a motivational source for activity. In this sense, situated artifacts gently nudge toward sustainable health behavior change.2025JKJonas Keppel et al.Fitness Tracking & Physical Activity MonitoringSleep & Stress MonitoringDIS
PromptMap: An Alternative Interaction Style for AI-Based Image GenerationRecent technological advances popularized the use of image generation among the general public. Crafting effective prompts can, however, be difficult for novice users. To tackle this challenge, we developed PromptMap, a new interaction style for text-to-image AI that allows users to freely explore a vast collection of synthetic prompts through a map-like view with semantic zoom. PromptMap groups images visually by their semantic similarity, allowing users to discover relevant examples. We evaluated PromptMap in a between-subject online study (n=60) and a qualitative within-subject study (n=12). We found that PromptMap supported users in crafting prompts by providing them with examples. We also demonstrated the feasibility of using LLMs to create vast example collections. Our work contributes a new interaction style that supports users unfamiliar with prompting in achieving a satisfactory image output.2025KAKrzysztof Adamkiewicz et al.Generative AI (Text, Image, Music, Video)Interactive Data VisualizationIUI
ProtoBricks: A Research Toolkit for Tangible Prototyping & Data PhysicalizationBuilding tangible interfaces or data physicalizations is a resource-intensive endeavour. There is a need for rapid means to prototype tangibles in order to facilitate research and design. To this end, we designed ProtoBricks: a research toolkit that uses capacitive bricks to facilitate rapid prototyping for tangible interfaces. Utilizing toy bricks that do not contain electronics, ProtoBricks can record brick position and color. Specialized knowledge is not required to build our system as it uses widely available components and 3D printing. We contribute the full software and hardware specification of the toolkit. We evaluate the utility of the toolkit by reporting on past use cases and prototyping workshops. We show that the toolkit facilitates creativity and effectively supports prototyping. ProtoBricks lowers the entry threshold for experimenting with tangible interfaces and enables researchers and designers to focus on the interaction with their prototype, delegating implementation to the toolkit.2024JDJulia Dominiak et al.Data PhysicalizationCircuit Making & Hardware PrototypingDIS
Screenless Interactive Tabletop Gaming with Capacitive Surface SensingMany interactive systems that support tabletop games either augment the experience with additional elements or transform game components into digital counterparts, e.g., using mixed reality. However, as many users prefer tangible game elements, digital augmentations can disrupt the immersion they seek to enhance, often due to the complexity of the hardware used. Responding to this challenge, we designed a screenless interactive tabletop system with capacitive sensing. The system is suitable for novice players and provides automatic score-keeping. Our method eliminates the need for external sensors and retains all original game pieces intact. We evaluated our system in a study with a forest planting game (n = 20). Gameplay with our system exhibited shorter turn duration, and participants adopted more effective strategies than in traditional gameplay. These results underscore the potential of screenless interactive tabletops to amplify the gaming experience without causing distractions.2024KAKrzysztof Adamkiewicz et al.Lodz University of TechnologySerious & Functional GamesDigitalization of Board & Tabletop GamesCHI
Exploring Recognition Accuracy of Vibrotactile Stimuli in Sternoclavicular AreaGrowing popularity of wearable haptic devices encouraged researchers to implement on-body interfaces that appropriate different form factors and interaction techniques. Among vibrotactile wearable interfaces, neck-worn devices gathered limited attention in HCI. While the ``necklace area'' offers wide opportunities for subtle haptic interaction, we lack knowledge of its tactile acuity to design interactive systems effectively. In this work, we present a prototype of HaptiNecklace - a vibrotactile necklace designed to study tactile acuity of sternoclavicular area. In the experimental study with N=19 participants, we compared recognition accuracy and cognitive load between different numbers of vibrotactile motors attached to the prototype in two scenarios -- static and mobile. The results show that directional patterns ensure better recognition than single-point vibrations in both mobile and static context. Moreover, introducing mobile scenario does not influence recognition accuracy but highly increases cognitive load. In this work, we provide practical hints to designing vibrotactile necklaces.2023MWMikołaj P. Woźniak et al.Vibrotactile Feedback & Skin StimulationHaptic WearablesUbiComp
SelVReflect: A Guided VR Experience Fostering Reflection on Personal ChallengesReflecting on personal challenges can be difficult. Without encouragement, the reflection process often remains superficial, thus inhibiting deeper understanding and learning from past experiences. To allow people to immerse themselves in and deeply reflect on past challenges, we developed SelVReflect, a VR experience which offers active voice-based guidance and a space to freely express oneself. SelVReflect was developed in an iterative design process (N=5) and evaluated in a user study with N=20 participants. We found that SelVReflect enabled participants to approach their challenge and its (emotional) components from different perspectives and discover new relationships between these components. By making use of the spatial possibilities in VR, they got a better understanding of the situation and of themselves. We contribute empirical evidence of how a guided VR experience can support reflection. We discuss opportunities and design requirements for guided VR experiences that aim to foster deeper reflection.2023NWNadine Wagener et al.University of BremenSocial & Collaborative VRImmersion & Presence ResearchInteractive Narrative & Immersive StorytellingCHI
The Walking Talking Stick: Understanding Automated Note-Taking in Walking MeetingsWhile walking meetings offer a healthy alternative to sit-down meetings, they also pose practical challenges. Taking notes is difficult while walking, which limits the potential of walking meetings. To address this, we designed the Walking Talking Stick---a tangible device with integrated voice recording, transcription, and a physical highlighting button to facilitate note-taking during walking meetings. We investigated our system in a three-condition between-subjects user study with thirty pairs of participants (N=60) who conducted 15-minute outdoor walking meetings. Participants either used clip-on microphones, the prototype without the button, or the prototype with the highlighting button. We found that the tangible device increased task focus, and the physical highlighting button facilitated turn-taking and resulted in more useful notes. Our work demonstrates how interactive artifacts can incentivize users to hold meetings in motion and enhance conversation dynamics. We contribute insights for future systems which support conducting work tasks in mobile environments2023LHLuke Haliburton et al.LMU MunichCollaborative Learning & Peer TeachingContext-Aware ComputingHome Voice Assistant ExperienceCHI
How Instructional Data Physicalization Fosters Reflection in Personal InformaticsThe ever-increasing number of devices quantifying our lives offers a perspective of high awareness of one's wellbeing, yet it remains a challenge for personal informatics (PI) to effectively support data-based reflection. Effective reflection is recognised as a key factor for PI technologies to foster wellbeing. Here, we investigate whether building tangible representations of health data can offer engaging and reflective experiences. We conducted a between-subjects study where n=60 participants explored their immediate blood pressure data in relation to medical norms. They either used a standard mobile app, built a data representation from LEGO bricks based on instructions, or completed a free-form brick build. We found that building with instructions fostered more comparison and using bricks fostered focused attention. The free-form condition required extra time to complete, and lacked usability. Our work shows that designing instructional physicalisation experiences for PI is a means of improving engagement and understanding of personal data.2023MBMarit Bentvelzen et al.Utrecht UniversityData PhysicalizationMental Health Apps & Online Support CommunitiesCHI
The Development and Validation of the Technology-Supported Reflection InventoryReflection is an often addressed design goal in Human-Computer Interaction (HCI) research. An increasing number of artefacts for reflection have been developed in recent years. However, evaluating if and how an interactive technology helps a user reflect is still complex. This makes it difficult to compare artefacts (or prototypes) for reflection, impeding future design efforts. To address this issue, we developed the Technology-Supported Reflection Inventory (TSRI), which is a scale that evaluates how effectively a system supports reflection. We first created a list of possible scale items based on past work in defining reflection. The items were then reviewed by experts. Next, we performed exploratory factor analysis to reduce the scale to its final length of nine items. Subsequently, we confirmed test-retest validity of our instrument, as well as its construct validity. The TSRI enables researchers and practitioners to compare prototypes designed to support reflection.2021MBMarit Bentvelzen et al.Utrecht UniversityUser Research Methods (Interviews, Surveys, Observation)Prototyping & User TestingCHI
Clairbuoyance: Improving Directional Perception for SwimmersWhile we usually have no trouble with orientation, our sense of direction frequently fails in the absence of a frame of reference. Open-water swimmers raise their heads to look for a reference point, since disorientation might result in exhaustion or even drowning. In this paper, we report on Clairbuoyance - a system that provides feedback about the swimmer's orientation through lights mounted on swimming goggles. We conducted an experiment with two versions of Clairbuoyance: Discrete signals relative to a chosen direction, and continuous signals providing a sense of absolute direction. Participants swam to a series of targets. Proficient swimmers preferred the discrete mode; novice users the continuous one. We determined that both versions of Clairbuoyance enabled reaching the target faster than without the help of the system, although the discrete mode increased error. Based on the results, we contribute insights for designing directional guidance feedback for swimmers.2019FKFrancisco Kiss et al.University of StuttgartFitness Tracking & Physical Activity MonitoringBiosensors & Physiological MonitoringCHI