The Representation and Control of Time in Tangible User Interfaces.

Tangible user interfaces provide a powerful and intuitive means of interacting with digital information, creating a seamless connection between the cyberspace of ‘bits’ and the physical world of ‘atoms’. Musical applications of tangible interfaces are successful because they solidify the ephemeral sounds and structure of music, presenting them to player as readily graspable bricks, pucks and tangible objects. This thesis proposes that a detailed study of how time may be used within tangible interfaces is required in order to allow a better understanding of how to design new systems with this capability. The challenge in designing tangible interfaces for temporal-media is also one of the things that makes the area exciting, namely that music and sounds are not existing physical objects; therefore representing them as objects provides the designer with a very wide selection of possibilities. The designer gets to decide what sound and musical structures look and feel like and how they be- have. Rather than following a prescriptive route of giving the designer a set of guidelines, this thesis takes the more open approach of creating a design-space and interaction model that can help synthesise new design ideas, helping to draw attention to lesser explored areas.

This thesis proposes and evaluates the temporal-MCRit interaction model; a conceptual model of how time can be used in tangible user interfaces, adapted from a standard TUI model. This new interaction model can be used to both analyse existing systems, and synthesise new ones. The aim in proposing the interaction model is to encourage the design of tangible interfaces that go beyond a simple spatial mapping of time, towards future designs that allow fluid, intuitive interaction with temporal digital media. The BeatBearing tangible rhythm sequencer is presented in this thesis as an instrument designed to explore the tTUI design space and develop the interaction model. Variations of the BeatBearing are compared to evaluate the ability of the temporal-MCRit in assisting the designer of new temporal-TUIs.

The challenge of designing tangible interfaces for handling temporal digital media breaks down into three main questions:

1. How can time be represented in a tangible interface?
2. How can time be controlled in a tangible interface?
3. Knowing the above, how can TUIs be designed for intuitive, powerful and enjoyable interaction with temporal digital media?

In answering these questions this thesis lays the foundations for the development of advanced temporal-TUIs (temporal media tangible user interfaces). The vision is to unite the ‘hands-on’ physicality and nuance of musical instruments and recording studio equipment with the power and functionality of conventional graphical computer-based digital media editing. The tangible user interface basis of this vision means that the system will not simply provide controls with which to manipulate a virtual representation, but actually embody the digital-media in the real world, allowing direct physical manipulation of the time-based based media. The temporal-TUI concept is influenced by, and addresses, the challenges raised by new ways of engaging with music. In particular, those techniques that allow the player to interact with music out of time, as opposed to instruments that allow only the real-time production of music. In addressing this challenge it is hoped that advances in temporal-TUIs will in turn engender and inspire many new types of music, performance and composition.