Design and applications of inkjet-printed flexible sensate surfaces

Abstract

We live in a world where everyday artifacts begin to be designed and augmented as media interfaces. New technologies based on this mission enable us to more easily sense, interact, and communicate with objects. However, the world is highly variable in physical forms. To achieve the vision of ubiquitous computing, common manmade objects need to be designed from the ground up to incorporate computers and sensors. Often, we find ourselves confined by existing sensing infrastructures that are not designed to adapt the complexity of the physical world. This dissertation presents a research platform to investigate design principles and applications for flexible sensate surfaces. This platform utilizes recent advancements in low-cost, roll-to-roll conductive inkjet printing technology as an enabler for creating a scalable, physically and functionally adaptive and customizable sensing system. This collection of work demonstrates design principles and examples in the following four areas: manufacturing, customizable computer aided design, fabrication with physical manipulation and multi-modal sensing techniques. Two types of manufacturing methods are used and characterized. The first approach customizes the sensing design in a digital environment, where users define the geometry, shape and sensing inputs in a computer and print out customized functional patterns. The second approach is sensor fabrication via physical manipulation, where the sensate surface is premanufactured and through an additive method (paneling linear sensor tape stripes), or a subtractive method (cutting a sensor sheet), and the shape and sensing targets are processed post-manufacturing. Lastly, I demonstrate three techniques for multimodal sensing - designing "target specific shapes" for different sensing targets, multiplexing single input electrodes with various analog circuits for near surface sensing (pressure, touch, folding, proximity sensing), and adding extra layers of chemical for the designed ad-hoc sensing target alteration. The outcome of this exploration combines emerging technologies to realize a new way of designing sensate surfaces for smart environments and objects and helps us rethink sensing as both a graphical design and a physical manipulation process. In the course of this thesis, I demonstrate these principals by designing, testing, and evaluating a variety of flexible sensate surfaces.