Rapid Construction of Functioning Physical Interfaces from Cardboard, Thumbtacks, Tin Foil and Masking Tape Scott E. Hudson and Jennifer Mankoff HCI Institute Carnegie Mellon University 5000 Forbes Ave, Pittsburgh, PA 15213 {hudson, jmankoff}@cs.cmu.edu ABSTRACT Rapid, early, but rough system prototypes are becoming a standard and valued part of the user interface design proc-ess. Pen, paper, and tools like Flash™ and Director™ are well suited to creating such prototypes. However, in the case of physical forms with embedded technology, there is a lack of tools for developing rapid, early prototypes. In-stead, the process tends to be fragmented into prototypes exploring forms that look like the intended product or ex-plorations of functioning interactions that work like the intended product – bringing these aspects together into full design concepts only later in the design process. To help alleviate this problem, we present a simple tool for very rapidly creating functioning, rough physical prototypes early in the design process – supporting what amounts to interactive physical sketching. Our tool allows a designer to combine exploration of form and interactive function, using objects constructed from materials such as thumb-tacks, foil, cardboard and masking tape, enhanced with a small electronic sensor board. By means of a simple and fluid tool for delivering events to “screen clippings,” these physical sketches can then be easily connected to any exist-ing (or new) program running on a PC to provide real or Wizard of Oz supported functionality. ACM Classification: H5.2 [Information interfaces and presentation]: User Interfaces. - Graphical user interfaces. General terms: Design, Human Factors Keywords: Tools, rapid prototyping of physical interfaces, sketching of interactive physical forms. INTRODUCTION Paper prototypes, sketches, and other early design proto-types are an important first step for many GUI designers. One reason they are valuable is the speed with which they can be constructed, tested, and thrown away or modified [18]. This allows early communication and discussion about potential designs both with users and with other product team members. Early, rough forms can be particu-lar valuable because of the way end-users react to them: they are often seen as unfinished, inducing end users to provide richer design suggestions [11]. However, as computing moves off the desktop and into other physical forms, paper prototypes have become less complete [15], functioning interactive prototypes tend to be limited to fixed forms, such as existing mobile devices [14], and rapid prototyping tools are likewise limited. As a result, designers tend to be constrained to either create pro-totypes that look like the final product (either physically, e.g. using media such as foam mockups, or visually, e.g. using tools such as Flash™) or work like the interactions envisioned for the final product (e.g. provide equivalent interaction via an on-screen simulation). As a result, as illustrated in Figure 1a, the design process often involves a splitting of form and interactivity early, with only a gradual combining of these into a full product design. This results in a less fluid process with potentially slower and weaker communication and iteration. The work described this paper seeks to alleviate this prob-lem at the earliest stages of prototyping with BOXES (Building Objects for eXploring Executable Sketches), a tool that enables rapid construction of early interactive physical prototypes that both look like and work like the intended product. As illustrated in Figure 1b, this allows for an integrated design process that combines form, inter-face, and function in an earlier and more fluid fashion. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. UIST’06, October 15–18, 2006, Montreux, Switzerland. Copyright 2006 ACM 1-59593-313-1/06/0010...$5.00. Early ConceptsFinal Product ConceptTime & Effort Form InteractionBOXESPhidgets, etc. ToolkitsCustom electronics & formInteractionForm (a) (b) Figure 1: BOXES helps to reduce the need for parallel but sepa-rate development of form and interface. 289Figure 2: A rough cut at a portable MP3 player that can play/pause (button under thumb) or stop a song. In the background, the on-screen implementation is visible. The “play” button (Thumbtack 0) causes a mouse click over the play button on the RealOne media player. Inset image is a close up of the physical sketch prototype with the BOXES circuit board cupped in the user’s hand. Designers using our tool can construct prototype forms from everyday objects like cardboard, thumbtacks, alumi-num foil and masking tape, and can implement the func-tionality for prototypes using any rapid prototyping lan-guage or existing interface on a PC. Thumbtacks and foil (optionally placed underneath tape and labeled) are touch sensitive when connected to BOXES and can be easily and rapidly (re)positioned on a piece of cardboard. A simple wire connects each thumbtack (op-tionally pressed through a foil patch of arbitrary shape and size) to a small sensor board, which in turn communicates with a PC through a USB connection. The designer can then assign on-screen functionality to each touch sensitive component. Functionality is defined in terms of translations into mouse and keyboard actions delivered to specific por-tions of the desktop. Thus, as illustrated in Figure 2, the designer of a portable MP3 player can cause a simulated mouse button click to be delivered to the “play” button of an on-screen media player when the user presses the thumbtack labeled “play.” The remainder of this paper is organized as follow: First, we describe how a designer might construct a simple appli-cation using our tool. We then describe the hardware and software implementation that makes BOXES possible. We used an iterative, designer-centered process to develop BOXES, and we end by describing the experiences of de-signers using our tool. BACKGROUND The