Ultra-low-power ring-based wireless tinymouseWireless mouse rings offer subtle, reliable pointing interactions for wearable computing platforms. However, the small battery below 27 mAh in the miniature rings restricts the ring's continuous lifespan to just 1-10 hours, because even low-powered wireless communication such as BLE is power-consuming for ring's continuous use. The ring's short lifespan frequently disrupts users' mouse use with the need for frequent charging. This paper presents picoRing mouse, enabling a continuous ring-based mouse interaction with ultra-low-powered ring-to-wristband wireless connectivity. picoRing mouse employs a coil-based impedance sensing named semi-passive inductive telemetry, allowing a wristband coil to capture a unique frequency response of a nearby ring coil via a sensitive inductive coupling between the coils. The ring coil converts the corresponding user's mouse input into the unique frequency response via an up to 449 uW mouse-driven modulation system. Therefore, the continuous use of picoRing mouse can last approximately 600 (8hrs use/day)-1000 (4hrs use/day) hours on a single charge of a 27 mAh battery while supporting subtle thumb-to-index scrolling and pressing interactions in real-world wearable computing situations.2025YLDongchi Li et al.Foot & Wrist InteractionContext-Aware ComputingUIST
Twin Meander Coil: Sensitive Readout of Battery-free On-body Wireless Sensors using Body-scale Meander Coils"Energy-efficient and unconstrained wearable sensing platforms are essential for ubiquitous healthcare and activity monitoring applications. This paper presents Twin Meander Coil for wirelessly connecting battery-free on-body sensors to a textile-based reader knitted into clothing. This connection is based on passive inductive telemetry (PIT), wherein an external reader coil collects data from passive sensor coils via the magnetic field. In contrast to standard active sensing techniques, PIT does not require the reader to power up the sensors. Thus, the reader can be fabricated using a lossy conductive thread and industrial knitting machines. Furthermore, the sensors can superimpose information such as ID, touch, rotation, and pressure on its frequency response. However, conventional PIT technology needs a strong coupling between the reader and the sensor, requiring the reader to be small to the same extent as the sensors' size. Thus, applying this technology to body-scale sensing systems is challenging. To enable body-scale readout, Twin Meander Coil enhances the sensitivity of PIT technology by dividing the body-scale meander-shaped reader coils into two parts and integrating them so that they support the readout of each other. To demonstrate its feasibility, we built a prototype with a knitting machine, evaluated its sensing ability, and demonstrated several applications. https://dl.acm.org/doi/10.1145/3494996"2023RTRyo Takahashi et al.Biosensors & Physiological MonitoringElectronic Textiles (E-textiles)On-Skin Display & On-Skin InputUbiComp
Efficient Adaptive Beacon Deployment Optimization for Indoor Crowd Monitoring Applications"The indoor crowd density monitoring system using BLE beacons is one of the effective ways to prevent overcrowded indoor situations. The indoor crowd density monitoring system consists of a mobile application at the user's side and the beacon sensor network as the infrastructure. Since the performance of crowd density monitoring highly depends on how BLE beacons are placed, BLE beacon placement optimization is fundamental research work. This research proposes a beacon deployment method EABeD to incrementally place the beacons adaptively to the latest signal propagation status. Also, EABeD reduces most walking and measurement labor costs by applying Bayesian optimization and the walking distance optimization algorithm. We conducted the placement optimization experiment in the wild environment and compared the results with placements derived by the simulation-based method and people. The result shows that our proposed method can achieve 26.4% higher detection coverage than the simulation-based approach, 23.2% and 5.2% higher detection coverage than the inexperienced person's solution and the expert's solution. As for the labor cost reduction, our proposed method can reduce 90.2% of the walking distance and 74.4% of the optimization time compared with optimization by the dense data gathering method. https://dl.acm.org/doi/10.1145/3569462"2023YZYang Zhen et al.Context-Aware ComputingSmart Cities & Urban SensingUbiComp
Designing and Evaluating the User Experience of Wearable Assistive Devices for Single-Sided DeafnessSingle-sided deafness (SSD) significantly restricts social participation in hearing/speaking cultures due to the person's difficulty hearing conversations on their deaf side. Although hearing aids for SSD are effective in social situations, the acceptance rate remains low at 4%. To address this problem, we designed and developed a bone conduction-based device to be worn with eyeglasses, involving 53 individuals with SSD including two authors. We conducted a four-week diary study comparing our proposed device with traditional Contralateral Routing of Signals (CROS) hearing aids and explored the factors that might affect the acceptance rate of assistive devices for SSD. The findings indicated that our design was more acceptable for users with SSD due to its effectiveness, social acceptability, and the ability for wearers to use other devices simultaneously, such as earbuds. Based on our results, we discuss implications for designing wearable assistive devices to promote greater acceptance among the target population.2023KTKen Takaki et al.The University of TokyoHaptic WearablesDeaf & Hard-of-Hearing Support (Captions, Sign Language, Vibration)CHI
Meander Coil++: A Body-scale Wireless Power Transmission Using Safe-to-body and Energy-efficient Transmitter CoilWearable devices for life-logging and healthcare have been studied, but the need for frequent charging imposes inconvenience for long-term use. Integrating textile-based wireless chargers (\textit{i.e.}, coil) into clothing enables sustainable wearable computing by charging the on-body devices in use. However, the electromagnetic field generated by conventional coil chargers strongly interferes with human body, and the high resistance of conductive threads leads to inefficient power delivery. This paper presents Meander Coil++, enabling safe, energy-efficient, and body-scale wireless power delivery. Meander Coil++ uses a wiring pattern that suppresses electromagnetic exposure to the human body without compromising power delivery performance and a liquid-metal-based low-loss conductive cord. With these advancements, Meander Coil++ transmits a few watts of power to on-body devices at 25\% DC-to-DC efficiency while complying with international safety guidelines regarding electromagnetic exposure. We envision Meander Coil++ can maintain multiple devices on body for weeks beyond the confines of their small battery capacity.2022RTRyo Takahashi et al.The University of TokyoSmartwatches & Fitness BandsBiosensors & Physiological MonitoringElectronic Textiles (E-textiles)CHI
Circuit Assemblies: Electronic Modules for Interactive 3D-PrintsThis pictorial presents Circuit Assemblies, a design system for beginners to create 3D-printed interactive objects with embedded electronics. Circuit Assemblies are modules used to create objects that light up, move, or spin using basic electronic components like LEDs, batteries, and motors. To support beginners incorporating Circuit Assemblies into 3D designs, a set of virtual components were added to Tinkercad, a popular browser-based 3D CAD application with over 10 million users. In this paper, we begin with a set of design considerations gathered from interviews with three K-12 educators that teach electronics. We then present four different Circuit Assembly modules designed with these considerations in mind, highlighting the unique challenges that arise from combining electronics and 3D design for beginners, both in CAD software and physical assembly.2021TTTiffany Tseng et al.Desktop 3D Printing & Personal FabricationCircuit Making & Hardware PrototypingCustomizable & Personalized ObjectsDIS
Exquisite Circuits: Collaborative Electronics Design through Drawing GamesWe present Exquisite Circuits, a novel collaborative circuit design approach that remixes the surrealist Exquisite Corpse drawing game for paper circuits. In this pictorial, five participants played the game and documented their design, fabrication, and thought processes during gameplay. From these results, we contribute lessons learned on how game elements like surprise, ambiguous goals, and shared responsibility open new ways of thinking about the expressive and collaborative design of technology. Exquisite Circuits, through paper circuitry's hybrid of aesthetic and functional design affordances, helps reveal tensions between arts and technology cultures and approaches. We invite educators, designers, and technology creators to try their own variations of the Exquisite Circuits and share their results with the creative technology community.2021JQJie Qi et al.Circuit Making & Hardware PrototypingMakerspace CultureC&C
LightTouch Gadgets: Extending Interactions on Capacitive Touchscreens by Converting Light Emission to Touch InputsWe present LightTouch, a 3D-printed passive gadget to enhance touch interactions on unmodified capacitive touchscreens. The LightTouch gadgets simulate finger operations such as tapping, swiping, and multi-touch gestures by means of conductive materials and light-dependent resistors (LDR) embedded in the object. The touchscreen emits visible light and the LDR senses the level of this light, which changes its resistance value. By controlling the screen brightness, it intentionally connects or disconnects the path between the GND and the touchscreen, thus allowing the touch inputs to be controlled. In contrast to conventional physical extensions for touchscreens, our technique requires neither continuous finger contact on the conductive part nor the use of batteries. As such, it opens up new possibilities for touchscreen interactions beyond the simple automation of touch inputs, such as establishing a communication channel between devices, enhancing the trackability of tangibles, and inter-application operations.2021KIKaori Ikematsu et al.Yahoo Japan CorporationCircuit Making & Hardware PrototypingCHI
Flower Jelly Printer: Slit Injection Printing for Parametrically Designed Flower JellyFlower jellies, a delicate dessert in which a flower-shaped jelly floats inside another clear jelly, fascinate people with both their beauty and elaborate construction. In efforts to simplify the challenging fabrication and enrich the design space of this dessert, we present Flower Jelly Printer: a printing device and design software for digitally fabricating flower jellies. Our design software lets users play with parameters and preview the resulting forms until achieving their desired shapes. We also developed slit injection printing that directly injects colored jelly into a base jelly, and shared several design examples to show the breadth of design possibilities. Finally, the user study with novice and experienced users demonstrates that our system benefits creators of all experience levels by iterative design and precise fabrication. We hope to enable more people to design and create their own flower jellies while expanding access and the design space for digitally fabricated foods.2021MMMako Miyatake et al.The University of TokyoDesktop 3D Printing & Personal FabricationCustomizable & Personalized ObjectsCHI
Pop-up Print: Rapidly 3D Printing Mechanically Reversible Objects in the Folded StateDespite recent advancements in 3D printing technology, which allows users to rapidly produce 3D objects, printing tall and/or large objects still consumes more time and large amount of support material. In order to address these problems, we propose Pop-up Print, a method to 3D print an object in a compact “folded” state and then unfold it after printing to achieve the final artifact. Using this method, we can reduce the object’s print height and volume, which directly affects the printing time and support material consumption. In addition, thanks to the reversibility of folding/unfolding, we can reversibly minimize the printed object’s volume when unused for storage or transportation, and expand it only in use. To achieve Pop-up Print, we first conducted an experiment using selected printed sample objects with several parameters, in order to determine suitable crease patterns that make both the unfolded and folded state mechanically stable. Based on this result, we developed an interactive design tool to convert 3D models – such as a Stanford Bunny or a Huffman’s cone – to the folded shape. Our design tool allows users to decide non-intuitive parameters that may affect the form’s mechanical stability, while maintaining both functional crease patterns and the object’s original form factor. Finally, we demonstrate the feasibility of our method through several examples of folded objects.2020YNKoya Narumi et al.Desktop 3D Printing & Personal FabricationShape-Changing Materials & 4D PrintingCustomizable & Personalized ObjectsUIST
poimo: Portable and Inflatable Mobility Devices Customizable for Personal Physical CharacteristicsDespite the recent growth in popularity of personal mobility devices (e.g., e-scooters and e-skateboards), they still suffer from limited safety and narrow design form factors, due to their rigid structures. On the other hand, inflatable interfaces studied in human-computer interaction can achieve large volume change by simple inflation/deflation. Inflatable structure also offers soft and safe interaction owing to material compliance and diverse fabrication methods that lead to a wide range of forms and aesthetics. In this paper, we propose poimo, a new family of POrtable and Inflatable MObility devices, which consists of inflatable frames, inflatable wheels, and inflatable steering mechanisms made of a mass-manufacturable material called drop-stitch fabric. First, we defined the basic material properties of a drop-stitch inflatable structure that is sufficiently strong to carry a person while simultaneously allowing soft deformation and deflation for storage and portability. We then implemented an interactive design system that can scan the user’s desired riding posture to generate a customized personal mobility device and can add the user’s shape and color preferences. To demonstrate the custom-design capability and mobility, we designed several 3D models using our system and built physical samples for two basic templates: a motorcycle and a wheelchair. Finally, we conducted an online user study to examine the usability of the design system and share lessons learned for further improvements in the design and fabrication of poimo.2020RNRyuma Niiyama et al.Micromobility (E-bike, E-scooter) InteractionShape-Changing Interfaces & Soft Robotic MaterialsCustomizable & Personalized ObjectsUIST
TelemetRing: A Batteryless and Wireless Ring-shaped Keyboard using Passive Inductive TelemetryTelemetRing is a batteryless and wireless ring-shaped keyboard that supports command and text entry in daily lives by detecting finger typing on various surfaces. The proposed inductive telemetry approach eliminates bulky batteries or capacitors from the ring part. Each ring consists of a sensor coil (the ring part itself), 1-DoF piezoelectric accelerometer, and varactor diode; moreover, it has different resonant frequencies. Typing shocks slightly shift the resonant frequency, and these are detected by a wrist-mounted readout coil. 5-bit chord keyboard is realized by attaching five sensor rings on five fingers. Our evaluation shows that the prototype achieved the tiny (6 g, 3.5 cm3) ring sensor and 89.7% of typing detection ratio.2020RTRyo Takahashi et al.Force Feedback & Pseudo-Haptic WeightFoot & Wrist InteractionCircuit Making & Hardware PrototypingUIST
Kirigami Haptic Swatches: Design Methods for Cut-and-Fold Haptic Feedback MechanismsKirigami Haptic Swatches demonstrate how kirigami and origami based structures enable sophisticated haptic feedback through simple cut-and-fold fabrication techniques. We leverage four types of geometric patterns: rotational erection system (RES), split-fold waterbomb (SFWB), the overlaid structure of SFWB and RES (SFWB+RES), and cylindrical origami, to render different sets of haptic feedback (i.e. linear, bistable, bouncing snap-through, and rotational force behaviors, respectively). In each structure, not only the form factor but also the force feedback properties can be tuned through geometric parameters. We experimentally analyzed and modeled the structures, and implemented software to automatically generate 2D patterns for desired haptic properties. We also demonstrate five example applications including an assistive custom keyboard, rotational switch, multi-sensory toy, task checklist, and phone accessories. We believe the Kirigami Haptic Swatches helps tinkerers, designers, and even researchers to create interactions that enrich our haptic experience.2020ZCZekun Chang et al.University of TokyoHaptic WearablesShape-Changing Interfaces & Soft Robotic MaterialsCHI
FoldTronics: Creating 3D Objects with Integrated Electronics Using Foldable Honeycomb StructuresWe present FoldTronics, a 2D-cutting based fabrication technique to integrate electronics into 3D folded objects. The key idea is to cut and perforate a 2D sheet to make it foldable into a honeycomb structure using a cutting plotter; before folding the sheet into a 3D structure, users place the electronic components and circuitry onto the sheet. The fabrication process only takes a few minutes allowing to rapidly prototype functional interactive devices. The resulting objects are lightweight and rigid, thus allowing for weight-sensitive and force-sensitive applications. Finally, due to the nature of the honeycomb structure, the objects can be folded flat along one axis and thus can be efficiently transported in this compact form factor. We describe the structure of the foldable sheet, and present a design tool that enables users to quickly prototype the desired objects. We showcase a range of examples made with our design tool, including objects with integrated sensors and display elements.2019JYJunichi Yamaoka et al.The University of Tokyo & Massachusetts Institute of TechnologyShape-Changing Materials & 4D PrintingCircuit Making & Hardware PrototypingCHI
Self-healing UI: Mechanically and Electrically Self-healing Materials for Sensing and Actuation InterfacesLiving things in nature have long been utilizing the ability to “heal” their wounds on the soft bodies to survive in the outer environment. In order to impart this self-healing property to our daily life interface, we propose Self-healing UI, a soft-bodied interface that can intrinsically self-heal damages without external stimuli or glue. The key material to achieving Self-healing UI is MWCNTs-PBS, a composite material of a self-healing polymer polyborosiloxane (PBS) and a filler material multi-walled carbon nanotubes (MWCNTs), which retain mechanical and electrical self-healability. We developed a hybrid model that combines PBS, MWCNTs-PBS, and other common soft materials including fabric and silicone to build interface devices with self-healing, sensing, and actuation capability. These devices were implemented by layer-by-layer stacking fabrication without glue or any post-processing, by leveraging the materials’ inherent self-healing property between two layers. We then demonstrated sensing primitives and interactive applications that extend the design space of soft interface with their ability to transform, conform, reconfigure, heal, and fuse, which we believe can enrich the toolbox of human-computer interaction (HCI).2019KNKoya Narumi et al.Haptic WearablesShape-Changing Interfaces & Soft Robotic MaterialsShape-Changing Materials & 4D PrintingUIST
Dynablock: Dynamic 3D Printing for Instant and Reconstructable Shape FormationThis paper introduces Dynamic 3D Printing, a fast and reconstructable shape formation system. Dynamic 3D Printing can assemble an arbitrary three-dimensional shape from a large number of small physical elements. Also, it can disassemble the shape back to elements and reconstruct a new shape. Dynamic 3D Printing combines the capabilities of 3D printers and shape displays: Like conventional 3D printing, it can generate arbitrary and graspable three-dimensional shapes, while allowing shapes to be rapidly formed and reformed as in a shape display. To demonstrate the idea, we describe the design and implementation of Dynablock, a working prototype of a dynamic 3D printer. Dynablock can form a three-dimensional shape in seconds by assembling 3,000 9 mm blocks, leveraging a 24 x 16 pin-based shape display as a parallel assembler. Dynamic 3D printing is a step toward achieving our long-term vision in which 3D printing becomes an interactive medium, rather than the means for fabrication that it is today. In this paper, we explore possibilities for this vision by illustrating application scenarios that are difficult to achieve with conventional 3D printing or shape display systems.2018RSRyo Suzuki et al.Shape-Changing Materials & 4D PrintingUIST
PEP (3D Printed Electronic Papercrafts): An Integrated Approach for 3D Sculpting Paper-Based Electronic DevicesWe present PEP (Printed Electronic Papercrafts), a set of design and fabrication techniques to integrate electronic based interactivities into printed papercrafts via 3D sculpting. We explore the design space of PEP, integrating four functions into 3D paper products: actuation, sensing, display, and communication, leveraging the expressive and technical opportunities enabled by paper-like functional layers with a stack of paper. We outline a seven-step workflow, introduce a design tool we developed as an add-on to an existing CAD environment, and demonstrate example applications that combine the electronic enabled functionality, the capability of 3D sculpting, and the unique creative affordances by the materiality of paper.2018HOHyunjoo Oh et al.University of Colorado BoulderDesktop 3D Printing & Personal FabricationCircuit Making & Hardware PrototypingCHI