Foldios are foldable interactive objects with embedded input sensing and output capabilities. Foldios combine the advantages of folding for thin, lightweight and shape-changing objects with the strengths of thin-film printed electronics for embedded sensing and output. To enable designers and end-users to create highly custom interactive foldable objects, we contribute a new design and fabrication approach. It makes it possible to design the foldable object in a standard 3D environment and to easily add interactive high-level controls, eliminating the need to manually design a fold pattern and low-level circuits for printed electronics. Second, we contribute a set of printable user interface controls for touch input and display output on folded objects. Moreover, we contribute controls for sensing and actuation of shape-changeable objects. We demonstrate the versatility of the approach with a variety of interactive objects that have been fabricated with this framework.

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.

PrintScreen is an enabling technology for digital fabrication of customized flexible displays using thin-film electroluminescence (TFEL). It enables inexpensive and rapid fabrication of highly customized displays in low volume, in a simple lab environment, print shop or even at home. We show how to print ultra-thin (120 µm) segmented and passive matrix displays in greyscale or multi-color on a variety of deformable and rigid substrate materials, including PET film, office paper, leather, metal, stone, and wood. The displays can have custom, unconventional 2D shapes and can be bent, rolled and folded to create 3D shapes. We contribute a systematic overview of graphical display primitives for customized displays and show how to integrate them with static print and printed electronics. Furthermore, we contribute a sensing framework, which leverages the display itself for touch sensing. To demonstrate the wide applicability of PrintScreen, we present application examples from ubiquitous, mobile and wearable computing.

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.

Sifting and sense-making of video collections are important tasks in many professions. In contrast to sense-making of paper documents, where physical structuring of many documents has proven to be key to effective work, interaction with video is still restricted to the traditional "one video at a time" paradigm. This paper investigates how interaction with video can benefit from paper-like displays that allow for working with multiple videos simultaneously in physical space. We present a corresponding approach and system called PaperVideo, including novel interaction concepts for both video and audio. These include spatial techniques for temporal navigation, arranging, grouping and linking of videos, as well as for managing video contents and simultaneous audio playback on multiple displays. An evaluation with users provides insights into how paper-based navigation with videos improves active video work.

Increasingly powerful mobile devices like the Apple iPhone empower learners to watch e-lectures not only at home but also in mobile learning scenarios virtually anywhere and anytime. However, state of the art mobile video browsers do not support learners in getting an overview on and navigating between the large amounts of semantically related e-lectures, which are available in various digital libraries. We contribute a novel user interface for the mobile use of e-lectures. Leveraging a spatial navigation metaphor, it supports both linear and nonlinear interaction within a single lecture, as well as the efficient navigation within large e-lecture libraries. Evaluation results show that our e-lecture browser significantly improves the learning process and leads to significantly higher efficiency and user satisfaction.