The BBC micro:bit is a pocket-sized, battery-powered device that introduces students to coding and computational thinking through the lens of physical computing. It can be incorporated in a variety of interactive projects and combined with a range of commercially available accessories. These include display shields that support richer user interaction with the micro:bit via a small colour screen and additional button inputs.

The ACM Lifelog Search Challenge (LSC) is an annual comparative benchmarking exercise that brings together researchers in the field of multimedia retrieval to evaluate interactive search systems using a large-scale multimodal lifelog dataset. This paper presents an overview of the ninth edition of the challenge (LSC’26), held as a workshop during the ACM International Conference on Multimedia Retrieval (ICMR ’26) in Amsterdam. To broaden its scope, the workshop now features three submission tracks: the traditional Challenge Track for real-time search performance, a new General Lifelog Research Track for theoretical and architectural advancements, and an additional Open Source Track aimed at enhancing reproducibility and reducing barriers to entry for new participants.

Consumer-level multi-material 3D printing with conductive thermoplastics enables fabrication of interactive elements for bespoke tangible devices. However, large feature sizes, high resistance materials, and limitations of printable control circuitry mean that deployable devices cannot be printed without post-print assembly steps. To address these challenges, we present Printegrated Circuits, a technique that uses traditional electronics as material to 3D print self-contained interactive objects. Embedded PCBs are placed into recesses during a pause in the print, and through a process we term Prinjection, conductive filament is injected into their plated-through holes. This automatically creates reliable electrical and mechanical contact, eliminating the need for manual wiring or bespoke connectors. We describe the custom machine code generation that supports our approach, and characterise its electrical and mechanical properties. With our 6 demonstrations, we highlight how the Printegrated Circuits process fits into existing design and prototyping workflows as well as informs future research agendas.

As hardware prototyping toolkits and accessible programming environments become more widespread, it is easier than ever to build functional prototypes of interactive devices. Yet moving beyond a prototype towards manufacturable devices still presents significant challenges. This evolution often requires specialised knowledge in circuit design, firmware development, and hardware testing, which can discourage less experienced creators. We present MakeDevice, a browser-based tool that helps users navigate this transition by leveraging the intuitive micro:bit, Jacdac and MakeCode ecosystem coupled with a process we call device flattening. Modular micro:bit-plus-Jacdac hardware assemblies are progressively transformed, or flattened, into increasingly-integrated custom printed circuit board (PCB) designs. We demonstrate MakeDevice through two examples. MakeDevice lowers barriers to the creation and deployment of new tangible, embedded and embodied devices by providing an alternative to the traditional PCB design process.

For the eighth time since 2018, the ACM Lifelog Search Challenge (LSC) was run to compare interactive lifelog search systems in a live metrics-based challenge. The goal of the LSC workshop is to comparatively evaluate the capabilities of systems accessing a large multimodal lifelog. LSC'25 attracted eleven participating teams, each of which had developed an innovative interactive lifelog retrieval system. The benchmark was organised in a hybrid manner (due to political issues in 2025) at the LSC workshop at ACM ICMR'25 in Chicago, USA. This short paper summarises the LSC workshop setting and presents the participating lifelog search systems.

In a world of generative models and large-scale data, it's insightful to revisit the intimate nature and unique value of personal multimedia through the lens of SenseCam - a wearable camera that automatically captures still images to create a visual diary for the wearer. Despite a variety of wearable camera products that have come to market in the decades since SenseCam was conceived, the unique properties of the original prototypes and the benefits these unlocked remain elusive today. Having explored why it has proven so challenging to move from a hardware prototype like SenseCam to a fully-fledged product with the same properties, I present a new phase of the prototyping-to-production journey I call isotyping. Isotyping shines a light on the critical, but often overlooked, steps necessary to scale from a promising prototype towards viable low-volume production. I call on the research community to help refine the concept and process of isotyping as we collectively continue to explore the potential of new forms of hardware in our research.

In an increasingly data-driven world, a core set of data literacy skills are needed to enable individuals and society collectively to make informed decisions. In this experience report we present the Toolkit for Educators of Data Science, a novel combination of hardware and software that empowers children in K-12 to experience the data science lifecycle by collecting, analysing, and visualising their own local environmental data. Through exploratory studies in two classrooms involving five teachers and 100 children aged 7 to 11, we experienced the following. (1) Collecting live data from the local environment with our tools provided children with high levels of agency, engagement and focus, (2) Educators stated how using the technology gave the data purpose and gave students a new perception and experience of computing; data started to have meaning because of the real world application across the curriculum. (3) The offline, standalone design of our toolkit empowers teachers by overcoming practical issues often associated with delivering data science lessons in schools.

The growing capabilities of microcontrollers, sensors, and actuators, coupled with decreasing costs, have led to a proliferation of embedded interactive systems. Prototyping such electronic systems has become democratized across a broad audience, including students, hobbyists, professional engineers, and programmers. Central to this evolution is the ease of software development, and in particular, the availability of low-level drivers and programming libraries which have significantly lowered the barriers to programming these systems. However, this ecosystem often presents challenges due to the tight coupling between programming libraries, drivers, and the underlying sensors and actuators. This frequently leads to compatibility issues. This paper introduces LogicGlue, which addresses these challenges by providing a platform-independent driver specification format. LogicGlue driver specifications allow hardware-independent application logic to be written, facilitating the process of interchanging components with minimal-to-no code adjustments. Unlike existing solutions, LogicGlue supports efficient interfacing via native communication protocols. This approach not only simplifies electronics prototyping but also ensures compatibility between various types of electronic components from different vendors. By reducing the complexity of hardware integration, LogicGlue enables a more seamless exploration of novel interactive behaviours and interfaces, forming a new tool for engineering interactive computing systems.

This workshop will bring together researchers and educators to imagine a future of low-cost, widely-available digital making for children, both within the STEAM classroom and beyond. In particular, we are interested in expanding the reach of digital making with programmable microcontrollers (such as Arduino, the BBC micro:bit, etc.) to underrepresented children in the STEAM fields, which includes historically excluded or marginalized children as well as those lacking access to computers and/or the Internet. Participants will report on their experience helping children learn about digital technology while creating wearables, robotics, environmental sensors and more. Participants who submit a position paper or work-in-progress report will have an opportunity to present their work and ideas. From these presentations, we will select emerging themes to discuss.

Physical computing has emerged as an effective approach to introducing computing and coding to students. One of the most popular enabling tools is the BBC micro:bit, well-known for its positive impact on teaching programming and driving engagement in the classroom. We extend these benefits by developing a new approach to coding with micro:bit: MicroCode. Unlike other experiences, MicroCode couples the micro:bit with a low-cost handheld accessory to enable live and portable programming via an on-device visual programming language; no separate host computer is needed. We present the design of MicroCode and the findings of a study in which we interviewed five primary school teachers and 60 children aged 10-11 working with MicroCode. The outcomes of the study show that MicroCode raised children’s engagement and stimulated the development of a strong sense of agency on coding activities, while teachers felt empowered to adopt situated and cross-curricular learning approaches.

For the seventh time since 2018, the Lifelog Search Challenge (LSC) benchmarked interactive lifelog search systems in a live challenge. The LSC goal is to comparatively evaluate system capabilities to access large multimodal lifelogs comprising hundreds of thousands of records. LSC'24 attracted an unprecedented record number of twenty-one participating teams, where each team proposes innovative ideas implemented to new or already established interactive lifelog retrieval systems. The benchmark was organised in front of a live audience at the LSC workshop at ACM ICMR'24 in Phuket, Thailand. This short paper summarises the LSC workshop setting and presents the participating lifelog search systems.

The traditional approach to programming embedded systems is monolithic: firmware on a microcontroller contains both application code and the drivers needed to communicate with sensors and actuators, using low-level protocols such as I2C, SPI, and RS232. In comparison, software development for the cloud has moved to a service-based development and operation paradigm: a service provides a discrete unit of functionality that can be accessed remotely by an application, or other service, but is independently managed and updated. We propose, design, implement, and evaluate a service-based approach to prototyping embedded systems called Jacdac. Jacdac defines a service specification language, designed especially for embedded systems, along with a host of specifications for a variety of sensors and actuators. With Jacdac, each sensor/actuator in a system is paired with a low-cost microcontroller that advertises the services that represent the functionality of the underlying hardware over an efficient and low-cost single-wire bus protocol. A separate microcontroller executes the user's application program, which is a client of the Jacdac services on the bus. Our evaluation shows that Jacdac supports a service-based abstraction for sensors/actuators at low cost and reasonable performance, with many benefits for prototyping: ease of use via the automated discovery of devices and their capabilities, substitution of same-service devices for each other, as well as high-level programming, monitoring, and debugging. We also report on the experience of bringing Jacdac to commercial availability via third-party manufacturers.

In this report we share a co-design process for developing more accessible alternatives to traditional keyboard and mouse interfaces, involving individuals with motor impairments. We describe our methodology, including initial discovery phases that inspired three subsequent co-design workshops with three individuals with motor impairments and 26 designers. Based on our experience, we highlight the importance of creating an equitable and effective dialogue between designers and individuals with motor impairments, emphasizing the personal nature of each participant’s experiences and the potential of technology as an enabler rather than a generic solution. Guided simulations and hands-on prototyping were employed to trigger meaningful conversations. We underscore the significance of “being with” during the co-design process and the importance of a transparent prototyping and development process for creating genuinely accessible and inclusive interactive systems. By sharing our findings and recommendations, we aim to assist researchers running future co-design workshops that involve prototyping with technology and people of diverse backgrounds.

We present AdHocProx, a system that uses device-relative, inside-out sensing to augment co-located collaboration across multiple devices, without recourse to externally-anchored beacons – or even reliance on WiFi connectivity.

Embedded devices are now commonplace, and hardware prototyping toolkits have become a popular approach for hobbyists and professionals to create embedded hardware prototypes. However, moving from prototype into small scale manufacture use introduces complexity and cost, restricting embedded device development ’beyond the prototype’. Challenges include the need to design custom PCB for manufacture, and the design and fabrication of a device enclosure to ensure the robust enough for deployment. In response, we present MakeDevice : a web-based tool that leverages an existing modular hardware prototyping platform, Jacdac, to enable low-complexity route to generate a custom ‘carrier’ PCB upon which modules can be mounted and electrically connected. MakeDevice also automatically generates CAD files for custom enclosures with apertures to suit. We show how such enclosures can be generated using 3D printing and 2D stencils. In this way, MakeDevice lowers the barriers in moving from prototype to viable low-volume deployment of embedded hardware.

We present the first toolkit that equips blind and visually impaired (BVI) developers with the tools to create accessible data displays. Called PSST (Physical computing Streaming Sensor data Toolkit), it enables BVI developers to understand the data generated by sensors from a mouse to a micro:bit physical computing platform. By assuming visual abilities, earlier efforts to make physical computing accessible fail to address the need for BVI developers to access sensor data. PSST enables BVI developers to understand real-time, real-world sensor data by providing control over what should be displayed, as well as when to display and how to display sensor data. PSST supports filtering based on raw or calculated values, highlighting, and transformation of data. Output formats include tonal sonification, nonspeech audio files, speech, and SVGs for laser cutting. We validate PSST through a series of demonstrations and a user study with BVI developers.

LaserFactory is an integrated fabrication process that augments a commercially available fabrication machine to support the manufacture of fully functioning devices without human intervention. In addition to creating 2D and 3D mechanical structures, LaserFactory creates conductive circuit traces with arbitrary geometries, picks-and-places electronic and electromechanical components, and solders them in place. To enable this functionality, we make four contributions. First, we build a hardware add-on to the laser cutter head that can deposit silver circuit traces and assemble components. Second, we develop a new method to cure dispensed silver using a CO2 laser. Third, we build a motion-based signaling method that allows our system to be readily integrated with commercial laser cutters. Finally, we provide a design and visualization tool for making functional devices with LaserFactory. Having described the LaserFactory system, we demonstrate how it is used to fabricate devices such as a fully functioning quadcopter and a sensor-equipped wristband. Our evaluation shows that LaserFactory can assemble a variety of differently sized components (up to 65g), that these can be connected by narrow traces (down to 0.75mm) that become highly conductive after laser soldering (3.2Ω/m), and that our acceleration-based sensing scheme works reliably (to 99.5% accuracy).

Technology has become increasingly pervasive in the creative and experimental environment of the avant-garde fashion runway, particularly in relation to its garments. However, several disciplines are often necessary when exploring technologies for the construction of expressive garments (e.g. garments that respond to their environment), creating a barrier for fashion designers that has limited their ability to leverage new technologies. To help overcome this barrier, we designed and deployed Brookdale, a prototyping system for wearable technology consisting of new plug-and-play hardware that can be programmed using drag-and-drop software. Brookdale was created using a 24-week participatory design process with 17 novice fashion-tech designers. At the end of the 24 week process, designers showcased their Brookdale-enhanced garment collections at an avant-garde fashion-tech runway show in New York City. We report on the experiences, outcomes, and lessons learned throughout this process, and describe results from interviews with the fashion-tech designers 16 weeks after the fashion show, demonstrating the lasting positive impact of Brookdale.

We present Project Tasca, a pocket-based textile sensor that detects user input and recognizes everyday objects that a user carries in the pockets of a pair of pants (e.g., keys, coins, electronic devices, or plastic items). By creating a new fabric-based sensor capable of detecting in-pocket touch and pressure, and recognizing metallic, non-metallic, and tagged objects inside the pocket, we enable a rich variety of subtle, eyes-free, and always-available input, as well as context-driven interactions in wearable scenarios. We developed our prototype by integrating four distinct types of sensing methods, namely: inductive sensing, capacitive sensing, resistive sensing, and NFC in a multi-layer fabric structure into the form factor of a jeans pocket. Through a ten-participant study, we evaluated the performance of our prototype across 11 common objects including hands, 8 force gestures, and 30 NFC tag placements. We yielded a 92.3% personal cross-validation accuracy for object recognition, 96.4% accuracy for gesture recognition, and a 100% accuracy for detecting NFC tags at close distance . We conclude by demonstrating the interactions enabled by our pocket-based sensor in several applications.

Low-cost microcontroller boards like the BBC micro:bit are used to engage and inspire students worldwide to learn more about computing. Easy-to-use web-based programming environments and low-cost hardware allow novices to build physical computing systems with the micro:bit – systems that sense and respond to the real world. However, devices such as the micro:bit may not capture the attention of every student, as the interests of some may lie in graphic design, animation, or other areas that are not the main focus of physical computing.

The hardware research and development communities have invested heavily in tools and materials that facilitate the design and prototyping of electronic devices. Numerous easy-to-access and easy-to-use tools have streamlined the prototyping of interactive and embedded devices for experts and led to a remarkable growth in non-expert builders. However, there has been little exploration of challenges associated with moving beyond a prototype and creating hundreds or thousands of exact replicas - a process that is still challenging for many. We interviewed 25 individuals with experience taking prototype hardware devices into low volume production. We systematically investigated the common issues faced and mitigation strategies adopted. We present our findings in four main categories: (1) gaps in technical knowledge; (2) gaps in non-technical knowledge; (3) minimum viable rigor in manufacturing preparation; and (4) building relationships and a professional network. Our study unearthed several opportunities for new tools and processes to support the transition beyond a working prototype to cost effective low-volume manufacturing. These would complement the aforementioned tools and materials that support design and prototyping.

The development of new hardware can be split into two phases: prototyping and production. A wide variety of tools and techniques have empowered people to build prototypes during the first phase, but the transition to production is still complex, costly and prone to failure. This means the second phase often requires an up-front commitment to large volume production in order to be viable. I believe that new tools and techniques can democratize hardware production. Imagine "DevOps for hardware" - everything from circuit simulation tools to re-usable hardware test jig designs; and from test-driven development for hardware to telepresence for remote factory visits. Supporting low volume production and organic scaling in this way would spur innovation and increase consumer choice. I encourage the UIST community to join me in pursuit of this vision.

Historically, embedded systems development has been a specialist skill, requiring knowledge of low-level programming languages, complex compilation toolchains, and specialist hardware, firmware, device drivers and applications. However, it has now become commonplace for a broader range of non-specialists to engage in the making (design and development) of embedded systems - including educators to motivate and excite their students in the classroom. This diversity brings its own set of unique requirements, and the complexities of existing embedded systems development platforms introduce insurmountable barriers to entry. In this paper we present the motivation, requirements, implementation, and evaluation of a new programming platform that enables novice users to create effective and efficient software for embedded systems. The platform has two major components: (1) Microsoft MakeCode (www.makecode.com), a web app that encapsulates an accessible IDE for microcontrollers; and (2) CODAL, an efficient component-oriented C++ runtime for microcontrollers. We show how MakeCode and CODAL combine to provide an accessible, cross-platform, installation-free, high level programming experience for embedded devices without sacrificing performance and efficiency.

Across the globe, it is now commonplace for educators to engage in the making (design and development) of embedded systems in the classroom to motivate and excite their students. This new domain brings its own set of unique requirements. Historically, embedded systems development requires knowledge of low-level programming languages, local installation of compilation toolchains, device drivers, and applications. For students and educators, these requirements can introduce insurmountable barriers.

For more than two decades, capacitive sensing has played a prominent role in human-computer interaction research. Capacitive sensing has become ubiquitous on mobile, wearable, and stationary devices - enabling fundamentally new interaction techniques on, above, and around them. The research community has also enabled human position estimation and whole-body gestural interaction in instrumented environments. However, the broad field of capacitive sensing research has become fragmented by different approaches and terminology used across the various domains. This paper strives to unify the field by advocating consistent terminology and proposing a new taxonomy to classify capacitive sensing approaches. Our extensive survey provides an analysis and review of past research and identifies challenges for future work. We aim to create a common understanding within the field of human-computer interaction, for researchers and practitioners alike, and to stimulate and facilitate future research in capacitive sensing.

The recent introduction of computer science (CS) education into schools in many countries has led to a surge in interest in programming tools and approaches which make CS concepts and tasks engaging, motivating and accessible to all. There is renewed interest in supporting learning through physical computing, which has been shown to be motivational whilst offering opportunities for collaboration and creativity. Within this context the BBC recently led a collaborative venture in the UK to develop a portable and low-cost programmable device. The consortium funded and produced one million devices, enough for every 11-12 year-old in the UK. In this paper, we report on what we believe to be the first study to investigate the usability and affordances of the BBC micro:bit. We interviewed 15 teachers and 54 pupils in schools in England about their experiences with the device who were, in general, enthusiastic about the potential of the BBC micro:bit. We describe pupils' experiences in terms of usability, creativity, the tangibility of the device and their learning of programming, and analyse their experiences in the context of previously reported benefits of physical computing.

Expressiveness, which we define as the extent to which rich and complex intent can be conveyed through action, is a vital aspect of many human interactions. For instance, paint on canvas is said to be an expressive medium, because it affords the artist the ability to convey multifaceted emotional intent through intricate manipulations of a brush. To date, touch devices have failed to offer users a level of expressiveness in their interactions that rivals that experienced by the painter and those completing other skilled physical tasks. We investigate how data about hand movement -- provided by a motion sensor, similar to those found in many smart watches or fitness trackers -- can be used to expand the expressiveness of touch interactions. We begin by introducing a conceptual model that formalizes a design space of possible expressive touch interactions. We then describe and evaluate Expressy, an approach that uses a wrist-worn inertial measurement unit to detect and classify qualities of touch interaction that extend beyond those offered by today's typical sensing hardware. We conclude by describing a number of sample applications, which demonstrate the enhanced, expressive interaction capabilities made possible by Expressy.

We explore the design space of energy-neutral situated displays, which give physical presence to digital information. We investigate three central dimensions: energy sources, display technologies, and wireless communications. Based on the power implications from our analysis, we present a thin, wireless, photovoltaic-powered display that is quick and easy to deploy and capable of indefinite operation in indoor lighting conditions. The display uses a low-resolution e-paper architecture, which is 35 times more energy-efficient than smaller-sized high-resolution displays. We present a detailed analysis on power consumption, photovoltaic energy harvesting performance, and a detailed comparison to other display-driving architectures. Depending on the ambient lighting, the display can trigger an update every 1 -- 25 minutes and communicate to a PC or smartphone via Bluetooth Low-Energy.

Recent advances in materials science have resulted in a range of commercially viable and easy-to-use conductive inks which novices, hobbyists, educators, students and researchers are now using to design and build interactive circuits quickly. Despite the ease with which practitioners can construct working circuits, one of the major limitations of designing circuits on-the-fly is the difficulty of detecting and understanding errors in prototype circuits. As well as short- and open-circuits, which often prevent a circuit from working at all, more subtle issues like high resistance traces can result in poor performance. Many users can't readily work out how to successfully modify their circuits, and they often don't have the tools or expertise to measure the relevant circuit parameters. In this paper we present ConductAR, a tool which can recognize and analyze hand-drawn, printed and hybrid conductive ink patterns. An on-screen augmented reality style interaction helps users to understand and enhance circuit operation. A key element of ConductAR is its ability to calculate the resistance of a circuit using a camera attached to an off-the-shelf PC or tablet. Our sparse coding technique is fast enough to support rapid iterative prototyping on real circuits using a conductive ink marker and/or eraser as shown in Figure 1. The system thereby enhances the feasibility of circuit prototyping with conductive ink.

Different battery chemistries perform better on different axes, such as energy density, cost, peak power, recharge time, longevity, and efficiency. Mobile system designers are constrained by existing technology, and are forced to select a single chemistry that best meets their diverse needs, thereby compromising other desirable features. In this paper, we present a new hardware-software system, called Software Defined Battery (SDB), which allows system designers to integrate batteries of different chemistries. SDB exposes APIs to the operating system which control the amount of charge flowing in and out of each battery, enabling it to dynamically trade one battery property for another depending on Application And/Or User Needs. Using microbenchmarks from our prototype SDB implementation, and through detailed simulations, we demonstrate that it is possible to combine batteries which individually excel along different axes to deliver an enhanced collective performance when compared to traditional battery packs.

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.

We present a novel approach to the construction of electronic prototypes which can support a variety of interactive devices. Our technique, which we call circuit stickers, involves adhering physical interface elements such as LEDs, sounders, buttons and sensors onto a cheap and easy-to-make substrate which provides electrical connectivity. This assembly may include control electronics and a battery for standalone operation, or it can be interfaced to a microcontroller or PC. In this paper we illustrate different points in the design space and demonstrate the technical feasibility of our approach. We have found circuit stickers to be versatile and low-cost, supporting quick and easy construction of physically flexible interactive prototypes. Building extra copies of a device is straightforward. We believe this technology has potential for design exploration, research proto-typing, education and for hobbyist projects.

In this paper we explore a new type of wearable computing device, an interactive identity badge. An embedded LCD presents dynamic information to the wearer and interaction is facilitated by sensing movement of the retractable string which attaches the unit to the wearer's belt. This form-factor makes it possible to interact using a single hand, providing lightweight and immediate access to a variety of information when it's not convenient to pick up, unlock and interact directly with a device like a smartphone. In this paper we present our prototype interactive badge, demonstrate the underlying technology and describe a number of usage scenarios and interaction techniques

This paper introduces a low cost, fast and accessible technology to support the rapid prototyping of functional electronic devices. Central to this approach of 'instant inkjet circuits' is the ability to print highly conductive traces and patterns onto flexible substrates such as paper and plastic films cheaply and quickly. In addition to providing an alternative to breadboarding and conventional printed circuits, we demonstrate how this technique readily supports large area sensors and high frequency applications such as antennas. Unlike existing methods for printing conductive patterns, conductivity emerges within a few seconds without the need for special equipment. We demonstrate that this technique is feasible using commodity inkjet printers and commercially available ink, for an initial investment of around US$300. Having presented this exciting new technology, we explain the tools and techniques we have found useful for the first time. Our main research contribution is to characterize the performance of instant inkjet circuits and illustrate a range of possibilities that are enabled by way of several example applications which we have built. We believe that this technology will be of immediate appeal to researchers in the ubiquitous computing domain, since it supports the fabrication of a variety of functional electronic device prototypes.

In this paper we present the features of a new physical device prototyping platform called Microsoft .NET Gadgeteer along with our initial experiences using it to teach computer science in high schools. Gadgeteer makes it easy for newcomers to electronics and computing to plug together modules with varied functionality and to program the resulting system's behavior. We believe the platform is particularly suited to teaching modern programming concepts such as object-oriented, event-based programming and it could be a timely addition to established teaching tools given the current interest in improving high school computer science education in some regions. We have run a number of pilot studies in the US and in the UK with students of varying age and ability. Our results indicate that the tangible and expressive nature of Gadgeteer helps to engage and motivate a diverse set of students. We were also pleasantly surprised by the level of polish and sophistication of the devices which were built. We hope to further explore the potential of Gadgeteer for teaching in future work and we encourage others to build on our experiences.

In this paper we present a number of different physical construction techniques for prototyping functional electronic devices. Some of these approaches are already well established whilst others are more novel; our aim is to briefly summarize some of the main categories and to illustrate them with real examples. Whilst a number of different tools exist for building working device prototypes, for consistency the examples we present here are all built using the Microsoft .NET Gadgeteer platform. Although this naturally constrains the scope of this study, it also facilitates a basic comparison of the different techniques. Our ultimate aim is to enable others in the field to learn from our experiences and the techniques we present.

We present a novel yet simple technique that mitigates the interference caused when multiple structured light depth cameras point at the same part of a scene. The technique is particularly useful for Kinect, where the structured light source is not modulated. Our technique requires only mechanical augmentation of the Kinect, without any need to modify the internal electronics, firmware or associated host software. It is therefore simple to replicate. We show qualitative and quantitative results highlighting the improvements made to interfering Kinect depth signals. The camera frame rate is not compromised, which is a problem in approaches that modulate the structured light source. Our technique is non-destructive and does not impact depth values or geometry. We discuss uses for our technique, in particular within instrumented rooms that require simultaneous use of multiple overlapping fixed Kinect cameras to support whole room interactions.

We present Interactive Generator (InGen), a self-powered wireless rotary input device capable of generating haptic or force feedback without the need for any external power source. Our approach uses a modified servomotor to perform three functions: (1) generating power for wireless communication and embedded electronics, (2) sensing the direction and speed of rotation, and (3) providing force feedback during rotation. While InGen is rotating, the device is capable of providing the sensation of detents or bumps, changes in stiffness, and abrupt stops using only power that is harvested during interaction. We describe the device in detail, demonstrate an initial 'TV remote control' application, and end with a discussion of our experiences developing the prototype and application. To the best of our knowledge, InGen is the first self-powered device, which also provides haptic feedback during operation. More broadly, this work demonstrates a new class of input sys-tems that uses human-generated power to provide feedback to the user and wirelessly communicate sensed information.

In this paper we describe the design and implementation of a new versatile, scalable and cost-effective sensate surface. The system is based on a new conductive inkjet technology, which allows capacitive sensor electrodes and different types of RF antennas to be cheaply printed onto a roll of flexible substrate that may be many meters long. By deploying this surface on (or under) a floor it is possible to detect the presence and whereabouts of users through both passive and active capacitive coupling schemes. We have also incorporated GSM and NFC electromagnetic radiation sensing and piezoelectric pressure and vibration detection. We report on a number of experiments which evaluate sensing performance based on a 2.5m x 0.3m hardware test-bed. We describe some potential applications for this technology and highlight a number of improvements we have in mind.

Home heating is a major factor in worldwide energy use. Our system, PreHeat, aims to more efficiently heat homes by using occupancy sensing and occupancy prediction to automatically control home heating. We deployed PreHeat in five homes, three in the US and two in the UK. In UK homes, we controlled heating on a per-room basis to enable further energy savings. We compared PreHeat's prediction algorithm with a static program over an average 61 days per house, alternating days between these conditions, and measuring actual gas consumption and occupancy. In UK homes PreHeat both saved gas and reduced MissTime (the time that the house was occupied but not warm). In US homes, PreHeat decreased MissTime by a factor of 6-12, while consuming a similar amount of gas. In summary, PreHeat enables more efficient heating while removing the need for users to program thermostat schedules.

We present a system for accurate real-time mapping of complex and arbitrary indoor scenes in variable lighting conditions, using only a moving low-cost depth camera and commodity graphics hardware. We fuse all of the depth data streamed from a Kinect sensor into a single global implicit surface model of the observed scene in real-time. The current sensor pose is simultaneously obtained by tracking the live depth frame relative to the global model using a coarse-to-fine iterative closest point (ICP) algorithm, which uses all of the observed depth data available. We demonstrate the advantages of tracking against the growing full surface model compared with frame-to-frame tracking, obtaining tracking and mapping results in constant time within room sized scenes with limited drift and high accuracy. We also show both qualitative and quantitative results relating to various aspects of our tracking and mapping system. Modelling of natural scenes, in real-time with only commodity sensor and GPU hardware, promises an exciting step forward in augmented reality (AR), in particular, it allows dense surfaces to be reconstructed in real-time, with a level of detail and robustness beyond any solution yet presented using passive computer vision.

Microsoft .NET Gadgeteer is a new prototyping platform that makes it easier to construct, program and shape new kinds of computing objects. It is comprised of modular hardware, software libraries and 3D CAD support. Together, these elements support the key activities involved both in the rapid prototyping and the small-scale production of custom embedded, interactive and connected devices. We propose to organize and run a studio at TEI 2010 where participants are introduced to the platform and its capabilities. Participants will work in groups, assembling electronic modules, writing software and designing a case or enclosure for their device. The end-result will be that each group develops a fully functional device, which can be exhibited at the TEI demo session.

We present Vermeer, a novel interactive 360° viewable 3D display. Like prior systems in this area, Vermeer provides viewpoint-corrected, stereoscopic 3D graphics to simultaneous users, 360° around the display, without the need for eyewear or other user instrumentation. Our goal is to over-come an issue inherent in these prior systems which - typically due to moving parts - restrict interactions to outside the display volume. Our system leverages a known optical illusion to demonstrate, for the first time, how users can reach into and directly touch 3D objects inside the display volume. Vermeer is intended to be a new enabling technology for interaction, and we therefore describe our hardware implementation in full, focusing on the challenges of combining this optical configuration with an existing approach for creating a 360° viewable 3D display. Initially we demonstrate direct involume interaction by sensing user input with a Kinect camera placed above the display. However, by exploiting the properties of the optical configuration, we also demonstrate novel prototypes for fully integrated input sensing alongside simultaneous display. We conclude by discussing limitations, implications for interaction, and ideas for future work.

KinectFusion enables a user holding and moving a standard Kinect camera to rapidly create detailed 3D reconstructions of an indoor scene. Only the depth data from Kinect is used to track the 3D pose of the sensor and reconstruct, geometrically precise, 3D models of the physical scene in real-time. The capabilities of KinectFusion, as well as the novel GPU-based pipeline are described in full. Uses of the core system for low-cost handheld scanning, and geometry-aware augmented reality and physics-based interactions are shown. Novel extensions to the core GPU pipeline demonstrate object segmentation and user interaction directly in front of the sensor, without degrading camera tracking or reconstruction. These extensions are used to enable real-time multi-touch interactions anywhere, allowing any planar or non-planar reconstructed physical surface to be appropriated for touch.

A human-powered user interface device sources its power from the physical effort required to operate it. This paper describes a technique by which a geared DC motor and a simple circuit can be used to enable interaction-powered rotary input devices. When turned, the circuit provides a temporary power source for an embedded device, and doubles as a sensor that provides information about the direction and rate of input. As a proof of concept, we have developed a general-purpose wireless input device -- called the Peppermill -- and illustrate its capabilities by using it as a remote control for a multimedia-browsing application.

Although interactive surfaces have many unique and compelling qualities, the interactions they support are by their very nature bound to the display surface. In this paper we present a technique for users to seamlessly switch between interacting on the tabletop surface to above it. Our aim is to leverage the space above the surface in combination with the regular tabletop display to allow more intuitive manipulation of digital content in three-dimensions. Our goal is to design a technique that closely resembles the ways we manipulate physical objects in the real-world; conceptually, allowing virtual objects to be 'picked up' off the tabletop surface in order to manipulate their three dimensional position or orientation. We chart the evolution of this technique, implemented on two rear projection-vision tabletops. Both use special projection screen materials to allow sensing at significant depths beyond the display. Existing and new computer vision techniques are used to sense hand gestures and postures above the tabletop, which can be used alongside more familiar multi-touch interactions. Interacting above the surface in this way opens up many interesting challenges. In particular it breaks the direct interaction metaphor that most tabletops afford. We present a novel shadow-based technique to help alleviate this issue. We discuss the strengths and limitations of our technique based on our own observations and initial user feedback, and provide various insights from comparing, and contrasting, our tabletop implementations

In this paper we present novel input devices that combine the standard capabilities of a computer mouse with multi-touch sensing. Our goal is to enrich traditional pointer-based desktop interactions with touch and gestures. To chart the design space, we present five different multi-touch mouse implementations. Each explores a different touch sensing strategy, which leads to differing form-factors and hence interactive possibilities. In addition to the detailed description of hardware and software implementations of our prototypes, we discuss the relative strengths, limitations and affordances of these novel input devices as informed by the results of a preliminary user study.

Interacting with mobile devices using touch can lead to fingers occluding valuable screen real estate. For the smallest devices, the idea of using a touch-enabled display is almost wholly impractical. In this paper we investigate sensing user touch around small screens like these. We describe a prototype device with infra-red (IR) proximity sensors embedded along each side and capable of detecting the presence and position of fingers in the adjacent regions. When this device is rested on a flat surface, such as a table or desk, the user can carry out single and multi-touch gestures using the space around the device. This gives a larger input space than would otherwise be possible which may be used in conjunction with or instead of on-display touch input. Following a detailed description of our prototype, we discuss some of the interactions it affords.

We introduce a new type of interactive surface technology based on a switchable projection screen which can be made diffuse or clear under electronic control. The screen can be continuously switched between these two states so quickly that the change is imperceptible to the human eye. It is then possible to rear-project what is perceived as a stable image onto the display surface, when the screen is in fact transparent for half the time. The clear periods may be used to project a second, different image through the display onto objects held above the surface. At the same time, a camera mounted behind the screen can see out into the environment. We explore some of the possibilities this type of screen technology affords, allowing surface computing interactions to extend 'beyond the display'. We present a single self-contained system that combines these off-screen interactions with more typical multi-touch and tangible surface interactions. We describe the technical challenges in realizing our system, with the aim of allowing others to experiment with these new forms of interactive surfaces.

We report on the results of a study using SenseCam, a "life-logging" technology in the form of a wearable camera, which aims to capture data about everyday life in order to support people's memory for past, personal events. We find evidence that SenseCam images do facilitate people's ability to connect to their past, but that images do this in different ways. We make a distinction between "remembering" the past, and "knowing" about it, and provide evidence that SenseCam images work differently over time in these capacities. We also compare the efficacy of user-captured images with automatically captured images and discuss the implications of these findings and others for how we conceive of and make claims about life-logging technologies.

ThinSight is a novel optical sensing system, fully integrated into a thin form factor display, capable of detecting multi-ple fingers placed on or near the display surface. We describe this new hardware in detail, and demonstrate how it can be embedded behind a regular LCD, allowing sensing without degradation of display capability. With our approach, fingertips and hands are clearly identifiable through the display. The approach of optical sensing also opens up the exciting possibility for detecting other physical objects and visual markers through the display, and some initial experiments are described. We also discuss other novel capabilities of our system: interaction at a distance using IR pointing devices, and IR-based communication with other electronic devices through the display. A major advantage of ThinSight over existing camera and projector based optical systems is its compact, thin form-factor making such systems even more deployable. We therefore envisage using ThinSight to capture rich sensor data through the display which can be processed using computer vision techniques to enable both multi-touch and tangible interaction.