A cuttable multi-touch sensor

We propose cutting as a novel paradigm for ad-hoc customization of printed electronic components. As a first instantiation, we contribute a printed capacitive multi-touch sensor, which can be cut by the end-user to modify its size and shape. This very direct manipulation allows the end-user to easily make real-world objects and surfaces touch-interactive, to augment physical prototypes and to enhance paper craft. We contribute a set of technical principles for the design of printable circuitry that makes the sensor more robust against cuts, damages and removed areas. This includes novel physical topologies and printed forward error correction. A technical evaluation compares different topologies and shows that the sensor remains functional when cut to a different shape.Deutsche Forschungsgemeinschaft (Cluster of Excellence Multimodal Computing and Interaction, German Federal Excellence Initiative

SensorTape: Modular and Programmable 3D-Aware Dense Sensor Network on a Tape

SensorTape is a modular and dense sensor network in a form factor of a tape. SensorTape is composed of interconnected and programmable sensor nodes on a flexible electronics substrate. Each node can sense its orientation with an inertial measurement unit, allowing deformation self-sensing of the whole tape. Also, nodes sense proximity using time-of-flight infrared. We developed network architecture to automatically determine the location of each sensor node, as SensorTape is cut and rejoined. Also, we made an intuitive graphical interface to program the tape. Our user study suggested that SensorTape enables users with different skill sets to intuitively create and program large sensor network arrays. We developed diverse applications ranging from wearables to home sensing, to show low deployment effort required by the user. We showed how SensorTape could be produced at scale using current technologies and we made a 2.3-meter long prototype.National Science Foundation (U.S.) (NSF award 1256082

Sticky Actuator: Free-Form Planar Actuators for Animated Objects

We propose soft planar actuators enhanced by free-form fabrication that are suitable for making everyday objects move. The actuator consists of one or more inflatable pouches with an adhesive back. We have developed a machine for the fabrication of free-from pouches; squares, circles and ribbons are all possible. The deformation of the pouches can provide linear, rotational, and more complicated motion corresponding to the pouch's geometry. We also provide a both manual and programmable control system. In a user study, we organized a hands-on workshop of actuated origami for children. The results show that the combination of the actuator and classic materials can enhance rapid prototyping of animated objects.National Science Foundation (U.S.) (Grant 1240383)National Science Foundation (U.S.) (Grant 1138967

PrintSense: a versatile sensing technique to support multimodal flexible surface interaction

We present a multimodal on-surface and near-surface sensing technique for planar, curved and flexible surfaces. Our technique leverages temporal multiplexing of signals coming from a universal interdigitated electrode design, which is printed as a single conductive layer on a flexible substrate. It supports sensing of touch and proximity input, and moreover is capable of capturing several levels of pressure and flexing. We leverage recent developments in conductive inkjet printing as a way to prototype electrode patterns, and combine this with our hardware module for supporting the full range of sensing methods. As the technique is low-cost and easy to implement, it is particularly well-suited for prototyping touch- and hover-based user interfaces, including curved and deformable ones

PhysioSkin: Rapid Fabrication of Skin-Conformal Physiological Interfaces

Advances in rapid prototyping platforms have made physiological sensing accessible to a wide audience. However, off-the-shelf electrodes commonly used for capturing biosignals are typically thick, non-conformal and do not support customization. We present PhysioSkin, a rapid, do-it-yourself prototyping method for fabricating custom multi-modal physiological sensors, using commercial materials and a commodity desktop inkjet printer. It realizes ultrathin skin-conformal patches (~1μm) and interactive textiles that capture sEMG, EDA and ECG signals. It further supports fabricating devices with custom levels of thickness and stretchability. We present detailed fabrication explorations on multiple substrate materials, functional inks and skin adhesive materials. Informed from the literature, we also provide design recommendations for each of the modalities. Evaluation results show that the sensor patches achieve a high signal-to-noise ratio. Example applications demonstrate the functionality and versatility of our approach for prototyping a next generation of physiological devices that intimately couple with the human body

Sensitive and Makeable Computational Materials for the Creation of Smart Everyday Objects

The vision of computational materials is to create smart everyday objects using the materi- als that have sensing and computational capabilities embedded into them. However, today’s development of computational materials is limited because its interfaces (i.e. sensors) are unable to support wide ranges of human interactions , and withstand the fabrication meth- ods of everyday objects (e.g. cutting and assembling). These barriers hinder citizens from creating smart every day objects using computational materials on a large scale. To overcome the barriers, this dissertation presents the approaches to develop compu- tational materials to be 1) sensitive to a wide variety of user interactions, including explicit interactions (e.g. user inputs) and implicit interactions (e.g. user contexts), and 2) makeable against a wide range of fabrication operations, such cutting and assembling. I exemplify the approaches through five research projects on two common materials, textile and wood. For each project, I explore how a material interface can be made to sense user inputs or activities, and how it can be optimized to balance sensitivity and fabrication complexity. I discuss the sensing algorithms and machine learning model to interpret the sensor data as high-level abstraction and interaction. I show the practical applications of developed computational materials. I demonstrate the evaluation study to validate their performance and robustness. In the end of this dissertation, I summarize the contributions of my thesis and discuss future directions for the vision of computational materials

Soft Inkjet Circuits: Rapid Multi-Material Fabrication of Soft Circuits using a Commodity Inkjet Printer

Despite the increasing popularity of soft interactive devices, their fabrication remains complex and time consuming. We contribute a process for rapid do-it-yourself fabrication of soft circuits using a conventional desktop inkjet printer. It supports inkjet printing of circuits that are stretchable, ultrathin, high resolution, and integrated with a wide variety of materials used for prototyping. We introduce multi-ink functional printing on a desktop printer for realizing multi-material devices, including conductive and isolating inks. We further present DIY techniques to enhance compatibility between inks and substrates and the circuits' elasticity. This enables circuits on a wide set of materials including temporary tattoo paper, textiles, and thermoplastic. Four application cases demonstrate versatile uses for realizing stretchable devices, e-textiles, body-based and re-shapeable interfaces

A Time of Flight on-Robot Proximity Sensing System for Collaborative Robotics

The sensor system presented in this work demonstrates the results of designing an industrial grade exteroceptive sensing device for proximity sensing for collaborative robots. The intention of this design\u27s application is to develop an on-robot small footprint proximity sensing device to prevent safety protected stops from halting a robot during a manufacturing process. Additionally, this system was design to be modular and fit on an size or shape robotic link expanding the sensor system\u27s use cases vastly. The design was assembled and put through a number of benchmark tests to validate the performance of the time of flight (ToF) sensor system when used in proximity sensing: Single Sensor Characterization, Sensor Overlap Characterization, and Sensor Ranging Under Motion. Through these tests, the ToF sensor ring achieves real time data throughput while minimizing blind spots. Lastly, the sensor system was tested at a maximum throughput load of 32 ToF sensors and maintained a stable throughput of data from all sensors in real time