DuoTouch is a passive attachment for capacitive touch panels that adds tangible input while minimizing content occlusion and loss of input area. It uses two contact footprints and two traces to encode motion as binary sequences and runs on unmodified devices through standard touch APIs. We present two configurations with paired decoders: an aligned configuration that maps fixed-length codes to discrete commands and a phase-shifted configuration that estimates direction and distance from relative timing. To characterize the system’s reliability, we derive a sampling-limited bound that links actuation speed, internal trace width, and device touch sampling rate. Through technical evaluations on a smartphone and a touchpad, we report performance metrics that describe the relationship between these parameters and decoding accuracy. Finally, we demonstrate the versatility of DuoTouch by embedding the mechanism into various form factors, including a hand strap, a phone ring holder, and touchpad add-ons.

We propose an approach to detect finger hover inputs on a smartphone screen using corneal reflection images captured by the device’s built-in front camera. This method requires no external sensors or hardware, enabling hover input detection in the near-screen space that is not directly visible to the camera. By leveraging a convolutional neural network (CNN), we estimate the two-dimensional position of a hovering finger and classify it into a predefined screen grid. Experimental results show that our model achieves approximately 95% accuracy for coarse grids and maintains over 88% accuracy for finer divisions. Furthermore, our system demonstrates real-time processing capability with an end-to-end latency of approximately 22 ms on a standard smartphone. These findings highlight the practical feasibility of camera-only hover sensing and suggest a wide range of touchless interaction applications, enabling touchless interaction when touch is undesirable, pre-touch UI adaptation, and accessibility support on commodity mobile devices.

Double-tap-to-zoom is a common gesture on mobile devices, but often applies a fixed scale factor, requiring users to manually adjust zoom levels via pinch gestures to achieve comfortable readability. This limitation is particularly critical for text content, especially for users with diverse visual needs. We propose a target-aware zooming technique that dynamically adjusts the scale factor based on content and user preferences, positioning the tapped text at a preferred screen location. A crowdsourced study (N = 269) identified design requirements, followed by quantitative (N = 12) and qualitative (N = 16) user studies demonstrating improved readability and reductions in task time, manual adjustments, and physical workload. Based on the results of these studies, we incorporated a context-aware feature that adjusts text size according to factors such as vision correction. This technique enhances usability without introducing new interaction methods, enabling more efficient navigation and improved reading experiences across diverse user needs and content formats.

Understanding smartphone users’ grasp postures can improve the mobile interaction experience; for instance, the user interface (UI) layout can be dynamically adjusted based on the detected grasp. In our previous work, we introduced ReflecTouch, a grasp posture detection method that leverages corneal reflection images captured by the front camera. Building on this, we conducted a follow-up study using crowdsourced experiments in uncontrolled, in-the-wild environments. Based on the results, we discuss design considerations and practical strategies, including recommendations for integrating ReflecTouch with complementary sensing modalities, such as touch and IMU-based methods, to enhance the model’s accuracy in real-world settings.

We present FoodSkin, a technique for adding interactive elements to foods by implementing edible circuits on the surface of the food. The circuit is easily fabricated using commercially available materials. Existing approaches to enhance the eating experience, such as presenting an electrical taste by making food part of an electronic circuit, are challenging to apply to foods with low water content due to their low conductivity. Our technique enables the integration of dry foods into an electronic circuit and provides displaying (e.g., smell or taste) and sensing (e.g., eating activity) functionalities. We describe our fabrication technique with a library of food materials that we can utilize, evaluate the conductivity and adhesion of the gold-leaf traces, introduce demonstrative applications, and conclude with a workshop we conducted to evaluate the accessibility of our technique. FoodSkin enriches the design space for the computer-augmented eating experience by enabling the digital fabrication of electronics on versatile materials, surfaces, and shapes of foods.

We present ShiftTouch, an attachment-type passive interface that provides multiple inputs for capacitive touchscreens with minimal screen occlusion. ShiftTouch utilizes multiple linear electrodes to control the fine displacement of the touch position. The touch input is activated under the electrodes when several adjacent electrodes are grounded simultaneously. Each input area shares several electrodes with neighboring input areas, and the touchscreen identifies each one by detecting the fine displacement of the touch position. ShiftTouch can effectively reduce the occlusion area while inheriting the advantages of existing touch extension interfaces, which are battery-free, freely detachable, and easy to construct. Depending on the number of inputs to implement, ShiftTouch can alleviate screen occlusion by up to 80.5% compared to existing approaches using finger-sized electrodes.

By sensing how a user is holding a smartphone, adaptive user interfaces are possible such as those that automatically switch the displayed content and position of graphical user interface (GUI) components following how the phone is being held. We propose ReflecTouch, a novel method for detecting how a smartphone is being held by capturing images of the smartphone screen reflected on the cornea with a built-in front camera. In these images, the areas where the user places their fingers on the screen appear as shadows, which makes it possible to estimate the grasp posture. Since most smartphones have a front camera, this method can be used regardless of the device model; in addition, no additional sensor or hardware is required. We conducted data collection experiments to verify the classification accuracy of the proposed method for six different grasp postures, and the accuracy was 85%.

Due to its natural warmth, wood is frequently used to produce touchable objects such as furniture and signboards. Laser cutting machines are becoming common in personal wood processing to cut and engrave wood. In this paper, we propose a method and workflow for producing various sensors and electrical circuits for interactive devices by partially carbonizing the wood surface with a laser cutting machine. Similar to wiring on a conventional printed circuit board (PCB), the carbonized part functions as a conductive electrical path. A method for creating electronic circuits and sensors made of carbon graphene on botanical materials has been proposed. This technique makes use of a raster-scanning femtosecond (fs) laser, which is less common for personal fabrication than a constant-wave (CW) laser. Moreover, raster-scanning requires a substantial amount of time to create a circuit that is mainly made of conductive lines. This paper extends the method with a defocused vector-scanning CW laser beam and reduces the time and cost required for fabrication. The proposed method uses an affordable CW laser cutter to fabricate an electrical circuit, including touch sensors, damage sensors, and load sensors on wood boards. The circuit can be easily connected to traditional PCBs and electric parts such as one-board microcomputers using metal screws and nails typically used in DIY woodworking. We develop ease of use software design tool that supports the creation and fabrication of carbon paths. In addition, we report on a series of investigations, including optimizing wood materials and laser parameters to establish design guidelines.

In this pictorial, we propose an approach to integrate electronics into a paper-woven craft. A paper-woven structure is formed by alternately and orthogonally weaving paper strips. The key idea is to add conductive layers to these strips by printing or transferring conductive materials. Our approach enables us to form the skeleton of an object and its wiring and sensor arrangement simultaneously. We explore the creative space of this approach, i.e., integrating functions such as sensing, display, and sound amplification into objects, for leveraging the paper-woven structure. We also outline the workflow of the approach, introduce a design support tool, and discuss example applications that combine the electronic-enabled functionality and woven structure.

We 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.

Kirigami 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.

Personal identification numbers (PINs) and grid patterns have been used for user authentication, such as for unlocking smartphones. However, they carry the risk that attackers will learn the PINs and patterns by shoulder surfing. We propose a secure authentication method called SheetKey that requires complicated and quick touch inputs that can only be accomplished with a sheet that has a pattern printed with conductive ink. Using SheetKey, users can input a complicated combination of touch events within 0.3 s by just swiping the pad of their finger on the sheet. We investigated the requirements for producing SheetKeys, e.g., the optimal disc diameter for generating touch events. In a user study, 13 participants passed through authentication by using SheetKeys at success rates of 78-87%, while attackers using manual inputs had success rates of 0-27%. We also discuss the degree of complexity based on entropy and further improvements, e.g., entering passwords on alphabetical keyboards.

We propose a 3D-printed interface, CAPath, in which conductive contact points are in a grid layout. This structure allows not only specific inputs (e.g., scrolling or pinching) but also general 2D inputs and gestures that fully leverage the "touch surface." We provide the requirements to fabricate the interface and implement a designing system to generate 3D objects in the conductive grid structure. The CAPath interface can be utilized in the uniquely shaped interfaces and opens up further application fields that cannot currently be accessed with existing passive touch extensions. Our contributions also include an evaluation for the recognition accuracy of the touch operations with the implemented interfaces. The results show that our technique is promising to fabricate customizable touch-sensitive interactive objects.

Humans can perceive tactile sensation through multimodal stimuli. To demonstrate realistic pseudo tactile sensation for the users, a tactile display is needed that can provide multiple tactile stimuli. In this paper, we have explicated a novel printed tactile display that can provide both the electrical stimulus and the electrostatic force. The circuit patterns for each stimulus were fabricated by employing the technique of double-sided conductive ink printing. Requirements for the fabrication process were analyzed and the durability of the tactile display was evaluated. Users' perceptions of a single tactile stimulus and multiple tactile stimuli were also investigated. The obtained experimental results indicate that the proposed tactile display is capable of exhibiting realistic tactile sensation and can be incorporated by various applications such as tactile sensation printing of pictorial illustrations and paintings. Furthermore, the proposed hybrid tactile display can contribute to accelerated prototyping and development of new tactile devices.

In this study, we propose a striped pattern sticker called ExtensionSticker that allows a touch input to be transferred from an external source by simply attaching the sticker to a touch panel. This allows the user to input touches or continuous scrolling actions by touching a sticker printed with stripes of conductive ink, without directly touching the touch panel. This method could be applied to the sides or back of a touch panel, or even the surface upon which a device is located as a touch interface, allowing us to freely construct interfaces in shapes matching the demands of the user. This paper also reports the results of evaluation experiments conducted to assess the recognition accuracy of scroll and tap actions using the proposed method.