PaperButtons: expanding a tangible user interface

Expanding the functionality of a successful system is always a challenge; the initial simplicity and ease-of-use is easily lost in the process. Experience indicates that this problem is worsened in systems with tangible interfaces: while it might be relatively easy to suggest a single successful tangible interaction component, it is notoriously hard to preserve the success when expanding with more components or more manipulation using the same component. This paper describes our approach to creating and expanding tangible interfaces. The approach consist of adherence to a set of guidelines for tangible interfaces, derived from practical tangible design and general object-oriented design, and solicitation of user requirements to the particular interaction method in question. Finally the paper describes a prototype of PaperButtons built in response to these requirements and designed in accordance to the guidelines for tangible interfaces.