Spark (above and
at right) achieves
September + October 2008
usually can’t wait for the design
team to consider each possible
combination of controls and
interactions, and so a designer
approaching a convergent problem must find a way to better
manage risk and reward than
simple trial and error.
While this may feel daunting, there are some simple steps
interaction designers can take
that will facilitate collaboration
with industrial designers and
engineers and lay useful foundations for interaction design.
Choosing the right controls
means building a successful
partnership between industrial
design, mechanical, electrical
and software engineering, and
Many interaction designers
focus on Internet and desktop
applications, where they are
supposedly freed from having to
make these types of decisions.
But it is worth noting that many
of the same skills that serve
designers when designing on-screen controls are required in
the physical realm too.
Discussing aesthetics or non-
functional aspects of product
design in a multidisciplinary
team setting can be challenging.
It can be helpful to gather imagery of a variety of comparative
products to understand what
has already been produced and
to discuss the relative merits of
A convergent designer can
help facilitate this conversation by asking people to evaluate controls in different ways.
Which are unique? Daunting?
Overplayed? Costly? Difficult
to use? Difficult to develop for?
This type of conversation, initiated at the beginning of a design
problem, will help the team
understand how different disciplines think about the problem.
This sort of exercise is easy
to conduct with clients or other
Framing the Design Challenge
Before diving into choosing
controls and making decisions,
there are several constraint-based decisions that should be
explicitly considered. Typically,
these constraints fall into two
buckets: those related to hard
or concrete development issues,
and those softer, more emotional
factors related to the person who
will eventually buy and love the
Constraints to consider:
• Cost: the actual cost of the
UI component or license that
directly affects the end cost.
Cost is especially important
when the product is highly com-moditized or when the business
model isn’t a direct purchase
by the consumer. Many medical
products that rely on subsidies
or reimbursement can be highly
• Development Complexity:
the effort needed to integrate a
control. For example, capacitive
controls require more electrical-engineering time to implement,
and developing a touch screen
can require additional software-development time.
• Size and Placement: especially on smaller devices, actual
components can be prohibitively
large. Designers will also need to
think about the overall layout of
controls. Is the product intended