Actuation and tangible user interfaces

In the last decade, the vision of future interfaces has shifted from virtual reality to augmented and tangible user interfaces (UI) where virtual and physical (or "bits and atoms") co-exist in harmony. Recently, a growing number of designers and researchers have been taking the next logical step: creating interfaces where physical, tangible elements are not merely dynamically coupled to the digital attributes and information, but are themselves dynamic, self-reconfigurable devices that can change their physical properties depending on the state of the interfaces, the user, or the environment.A combination of the actuation, self-configuration, and tangibility can expand and enhance the design of tangible interfaces. In this paper, we present an overview of the use of actuation in user interfaces and discuss the rationality of building actuated interfaces. We then discuss actuated interfaces in detail based on our experience designing Lumen shape displays. Work on actuated interfaces is still in its infancy, projects are few and far between, so we consider this paper an invitation to discussion and hope it can help stimulate further research in this area.