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196 Chapter 6 The process of interaction design

evaluated one at a time. Our version models a return to the activity of identifying needs and
establishing requirements after evaluating any element of the design.

Assignment
Nowadays, timepieces (such as clocks, wristwatches etc) have a variety of functions. They not
only tell the time and date but they can speak to you, remind you when it's time to do some-
thing, and provide a light in the dark, among other things. Mostly, the interface for these de-
vices, however, shows the time in one of two basic ways: as a digital number such as 23:40 or
through an analog display with two or three hands-one to represent the hour, one for the
minutes, and one for the seconds.
In thb assignment, we want you to design an innovative timepiece for your own use. This
could be in the form of a wristwatch, a mantelpiece clock, an electronic clock, or any other
kind of clock you fancy. Your goal is to be inventive and exploratory. We have broken this as-
I
signment down into the following steps to make it clearer:
I
(a) Think about the interactive product you are designing: what do you want it to do I
for you? Find 3-5 potential users and ask them what they would want. Write a list
of requirements for the clock, together with some usability criteria based on the de- 1
finition of usability used in Chapter 1.
(b) Look around for similar devices and seek out other sources of inspiration that you
might find helpful. Make a note of any findings that are interesting, useful or in-
sightful.
(c) Sketch out some initial designs for the clock. Try to develop at least two distinct al-
ternatives that both meet your set of requirements.
(d) Evaluate the two designs, using your usability criteria and by role playing an interac-
tion with your sketches. Involve potential users in the evaluation, if possible. Does it
do what you want? Is the time or other information being displayed always clear?
Design is iterative, so you may want to return to earlier elements of the process be-
fore you choose one of your alternatives.
Once you have a design with which you are satisfied, you can send it to us and we shall
post a representative sample of those we receive to our website. Details of how to format
your submission are available from our website.

Summary

In this chapter, we have looked at the process of interaction design, i.e., what activities are
required in order to design an interactive product, and how lifecycle models show the rela-
tionships between these activities. A simple interaction design model consisting of four ac-
tivities was introduced and issues surrounding the identification of users, generating
alternative designs, and evaluating designs were discussed. Some lifecycle models from soft-
ware engineering and HCI were introduced.

Key points
The interaction design process consists of four basic activities: identifying needs and es-
tablishing requirements, developing alternative designs that meet those requirements,
building interactive versions of the designs so that they can be communicated and as-
sessed, and evaluating them.