Rapid prototyping is an important tool for designers, but many fabrication techniques are slow and create bulky components requiring multiple machines and processes to achieve desired device shape and electronic functionality. Prior work explored ways to ease fabricating shapes or designing electronics, but we focus on creating shape and electrical pathways at the same time from a single material and machine. LaCir leverages a three-layered, laser-cuttable material to incorporate circuits into the structural substrate of the design using laser cutters. Our substrate features a layer of conductive material sandwiched between thermoplastic sheets, allowing designers to cut electrical traces and assembleable, 3D object geometry in a single pass. We evaluate different composite materials, weighing their cuttability, ease of assembly, and conductivity; we also show using fully laser-cut joints as structural and electrical connections. We demonstrate LaCir’s flexibility through several example artifacts.

Touchscreens provide a platform for adaptable and versatile user interfaces making them a popular choice for modern smart devices. However, touchscreens lack physicality. Existing solutions to add tangible user interfaces to smart devices often require complicated assembly or occlude part of the touchscreen. We propose ClipWidgets: 3D-printed modular tangible UI extensions for smartphones. ClipWidgets uses a conical mirror and a custom phone case to redirect the field of view of the rear camera of a smartphone to the phone’s periphery. This allows the phone to optically sense input from modular passive 3D-printed widgets that are attached to the phone case. We developed three different widget types (button, dial and slider) that require minimal calibration and minimal assembly. To demonstrate the functionality of ClipWidgets we used it to prototype three different applications: a game controller, a music interface and an interactive graph tool.

Researchers have developed various tools and techniques towards the vision of on-demand fabrication of custom, interactive devices. Recent work has 3D-printed artefacts like speakers, electromagnetic actuators, and hydraulic robots. However, these are non-trivial to instantiate as they require post-fabrication mechanical– or electronic assembly. We introduce AirLogic: a technique to create electronics-free, interactive objects by embedding pneumatic input, logic processing, and output widgets in 3D-printable models. AirLogic devices can perform basic computation on user inputs and create visible, audible, or haptic feedback; yet they do not require electronic circuits, physical assembly, or resetting between uses. Our library of 13 exemplar widgets can embed AirLogic-style computational capabilities in existing 3D models. We evaluate our widgets’ performance—quantifying the loss of airflow (1) in each widget type, (2) based on printing orientation, and (3) from internal object geometry. Finally, we present five applications that illustrate AirLogic’s potential.

Toolkits for shape-changing interfaces (SCIs) enable designers and researchers to easily explore the broad design space of SCIs. However, despite their utility, existing approaches are often limited in the number of shape-change features they can express. This paper introduces MorpheesPlug , a toolkit for creating SCIs that covers seven of the eleven shape-change features identified in the literature. MorpheesPlug is comprised of (1) a set of six standardized widgets that express the shape-change features with user-definable parameters; (2) software for 3D-modeling the widgets to create 3D-printable pneumatic SCIs; and (3) a hardware platform to control the widgets. To evaluate MorpheesPlug we carried out ten open-ended interviews with novice and expert designers who were asked to design a SCI using our software. Participants highlighted the ease of use and expressivity of the MorpheesPlug.

3D printing technology can be used to rapidly prototype the look and feel of 3D objects. However, the objects produced are passive. There has been increasing interest in making these objects interactive, yet they often require assembling components or complex calibration. In this paper, we contribute AirTouch, a technique that enables designers to fabricate touch-sensitive objects with minimal assembly and calibration using pneumatic sensing. AirTouch-enabled objects are 3D printed as a single structure using a consumer-level 3D printer. AirTouch uses pre-trained machine learning models to identify interactions with fabricated objects, meaning that there is no calibration required once the object has completed printing. We evaluate our technique using fabricated objects with various geometries and touch sensitive locations, obtaining accuracies of at least 90% with 12 interactive locations.

While pressing can enable a wide variety of interesting applications, most press sensing techniques operate only at close distances and rely on fragile electronics. We present EchoTube, a robust, modular, simple, and inexpensive system for sensing low-resolution press events at a distance. EchoTube works by emitting ultrasonic pulses inside a flexible tube which acts as a waveguide and detecting reflections caused by deformations in the tube. EchoTube is deployable in a wide variety of situations: the flexibility of the tubes allows them to be wrapped around and affixed to irregular objects. Because the electronic elements are located at one end of the tube, EchoTube is robust, able to withstand crushing, impacts, water, and other adverse conditions. In this paper, we detail the design, implementation, and theory behind EchoTube; characterize its performance under different configurations; and present a variety of exemplar applications that illustrate its potential.

We present Bitey, a subtle, wearable device for enabling input via tooth clicks. Based on a bone-conduction microphone worn just above the ears, Bitey recognizes the click sounds from up to five different pairs of teeth, allowing fully hands-free interface control. We explore the space of tooth input and show that Bitey allows for a high degree of accuracy in distinguishing between different tooth clicks, with up to 94% accuracy under laboratory conditions for five different tooth pairs. Finally, we illustrate Bitey's potential through two demonstration applications: a list navigation and selection interface and a keyboard input method.