Making a Paper Prototype - Paper Prototyping: The Fast and Easy Way to Define and Refine User Interfaces - page 70

every field.) Unless your interface relies heavily on function keys or key combinations, trying to use a
physical keyboard will only slow you down, without adding much useful information. As explained in
Chapter 12 , if you truly have a need to study keystroke (or mouse) level interactions, a paper prototype
is probably not the best choice.
Hardware Devices
Sometimes there's no computer monitor—the user is interacting only with a piece of equipment and its
set of buttons, knobs, lights, and so forth. In this case, the definition of "paper" prototyping stretches to
include cardboard, Fome-Cor, or other materials used to build 3D prototypes. This technique is useful
for a variety of hardware devices, including instrument panels, medical equipment, handheld devices,
and consumer appliances.
In one project, researchers Säde, Nieminen, and Riihiaho (1998) were asked by a manufacturer to help
design a can-recycling machine for consumers. There were two main ideas for the design—a "manual"
version where the user had to insert the can horizontally a certain way so that the machine could read
its bar code and an "automatic" version where the machine could read a vertically inserted can
regardless of its orientation. The interface was very limited (no text, just a diagram and three indicator
lights) and the design goal ambitious: All supermarket customers must be able to instantly use the
machine.
After making a mock-up of each design (shown in Figure 4.19 ), the researchers tested both versions at
a supermarket. Volunteer shoppers were given a bag full of cans and asked to recycle them. One of
the researchers was obviously visible behind the machine to accept or reject the cans while another
stuck colored bits of paper on the front to simulate the indicator lights. Although crude, this method of
testing was sufficient for the researchers to conclude that there was a significant difference in usability:
The automatic version worked well, but about half the participants would not have been able to recycle
their cans with the manual concept. They also discovered some unexpected user actions, such as
placing rejected cans on top of the machine. The manufacturer built a prototype of the automatic
version that incorporated the findings from the mock-up, and it also performed well in usability testing.
Eventually this machine went into production and is still being used today.
Figure 4.19: The mock-up of the manual version of the can recycling machine. In testing, a visible
researcher stood behind the machine to accept or reject each can while another used colored
pieces of paper to simulate the indicator lights.
"Incredibly Intelligent Help"
My mentor, Jared Spool, taught me one of my favorite paper prototyping tactics, called incredibly
intelligent help. It can be used before the online help or print documentation has been developed. This
tactic is used not only to refine the help or manual but in many cases to improve the interface itself.
When users gets stuck, the facilitator prompts them to ask a question about what's confusing them.