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3.1. Proactive Furniture
37
familiar with or has to learn before. We decided to use LED’s in the furniture
assembly task to guide users through the assembly process, since LED’s o er an
e cient way of drawing the user’s attention to certain objects.
This enables users to explore how the furniture has to be assembled. Users unwrap
the flat-pack furniture and their attention gets directed immediately (feedback type
1) to the parts they are supposed to start with. Users’ actions, such as turning
and moving boards, are sensed. Blinking green light patterns indicate which edges
have to be connected in which manner. If boards are aligned in the proper way,
a synchronized green light pattern on both edges indicates a well-performed action
(feedback type 2). If the user takes a wrong action, a red light pattern appears
representing a mistake (feedback type 3, see Figure 3(b)). Additionally, a green flash
pattern shows the alternative. After boards have been aligned correctly, individual
green lights direct the user’s attention to the holes where screws have to be inserted
and tightened (feedback type 4).
The light patterns extend a part’s static a ordances and can teach the user how
parts fit together in a learning-by-doing manner: As a physical notion of undo and
redo, connected boards can be continuously detached and rearranged, which fosters
explorability. Furthermore, the LED’s also contribute predictability to the assembly,
as red (green) light immediately indicates a correct (wrong) action. Intrinsic guid-
ance is provided by dynamic instructions that adapt to the current assembly state.
This allows the user to perform any sequence of actions without being constrained
to a certain predefined linear sequence.
To present instructions to the user, we have developed a hardware implementation
based on a custom layout board carrying eight dual green/red LED’s (see Figure
3.4(b)). Besides only presenting information using the LED’s we have the possi-
bility to provide visual and auditory voice instructions on a laptop computer (see
[
Michahelles et al. 2003a
]
for further information).
In the following sections we examine whether LED based instructions can supply
su cient information to enable the safe assembly of a piece of furniture. In addition,
we study if this type of instructions is easier to understand than classic instructions,
or even more intuitive. Finally, we test if instructions that are integrated into
objects have the potential to be less distracting (of the user’s attention) than classic
instructions.
3.1.4 User Evaluation of Proactive Furniture Instructions
To evaluate the use of LED based instructions, we set up an assembly task, that users
could complete in approximately 1-2 minutes. In this section we present the assembly
task used for the study and give an overview over the employed methodology.
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