interaction at architectural scale. We think of this as an approach to implement scaling in HCI.

To illustrate these ideas of small-scale interfaces that allow for playful, large-scale interaction with the atmosphere of a building, we will now introduce our design project the Light Dice. This prototype was inspired by the ideas of speculative design [ 6]; we introduce it here as an example of individual interaction at architectural scale.

DESIGNING THE LIGHT DICE—PLAYFUL HBI WITH AN ALTERNATIVE LIGHT SWITCH

Traditional wall-mounted light
switches might be one of the most
common and lightweight ways for
individuals to interact with the built
environment. A light switch enables
an individual to change the lighting
conditions, and thus the atmosphere,
of a room with a single finger. As such,
it is a lightweight design of a simple
interface that allows for HBI.

So how can we reimagine this ubiquitous button—the traditional light switch—from the viewpoint of interactive systems design and scaling interaction? Here we present one such design project, where we have implemented an asymmetrical interaction model to allow for playful interaction (at an individual level) with two interactive dice that serve as a light switch for a room. By staying close to this idea of unifying different scales, the Light Dice show what the scaling of interaction might offer as we move from HCI to HBI.

In designing the Light Dice system,
we discussed ways of moving beyond
the traditional and functional on/off
light switch. We considered interaction
with a light switch as something we
environments, as well as more
recent work on so-called interactive
architecture [ 1].

Still, less is known about how to scale the interaction model from the individual to the building. One basic reason might be that for traditional interaction design, input and output are typically implemented at the same scale, usually that of the individual.

For example, the multitouch display on a mobile phone is large enough to work as an interface for input (say, to fit a representation of a keyboard, with keys large enough for the fingers to click on), as well as large enough for displaying information (text and graphics can be displayed and read).

With one such implementation, the interaction model is at the scale of the individual, and the model is also symmetrical in terms of the scale of the input and output modalities. However, for any HBI solution to work, the input modality needs to be at individual scale, whereas the output might need to be at architectural scale. As such, an HBI interaction model might need to be asymmetrical to allow for individual

For any HBI solution to
work, the input modality
needs to be at individual
scale, whereas the
output might need to be
at architectural scale.

Final implementation of the Light Dice.