Custom-made tangible interfaces with touchtokens

TouchTokens were introduced recently as a means to design low-cost tangible interfaces. The technique consists in recognizing multi-touch patterns associated with specific tokens, and works on any touch-sensitive surface, with passive tokens that can be made out of any material. TouchTokens have so far been limited to a few basic geometrical shapes only, which puts a significant practical limit to how tailored token sets can be. In this article, we introduce TouchTokenBuilder and TouchTokenTracker that, taken together, aim at facilitating the development of tailor-made tangible interfaces. TouchTokenBuilder is an application that assists interface designers in creating token sets using a simple direct-manipulation interface. TouchTokenTracker is a library that enables tracking the tokens' full geometry. We report on experiments with those tools, showing the strengths and limitations of tangible interfaces with passive tokens.