Chapter 11: Design, Prototyping and Construction

Chapter Introduction | Web Resources | Assignment Comments | Teaching Materials


The main aims of this chapter are to:

  • Describe prototyping and different types of prototyping activities.
  • Enable you to produce simple prototypes from the models developed during the requirements activity.
  • Enable you to produce a conceptual model for a product and justify your choices.
  • Explain the use of scenarios and prototypes in design.
  • Introduce physical computing kits and software development kits, and their role in construction.


Design activities begin once some requirements have been established. The design emerges iteratively, through repeated design–evaluation–redesign cycles involving users. Broadly speaking, there are two types of design: conceptual and concrete. The former is concerned with developing a conceptual model that captures what the product will do and how it will behave, while the latter is concerned with details of the design such as menu structures, haptic feedback, physical widgets, and graphics. As design cycles become shorter, the distinction between these two becomes blurred, but they are worth distinguishing because each emphasizes a different set of design concerns.

For users to evaluate the design of an interactive product effectively, designers must prototype their ideas. In the early stages of development, these prototypes may be made of paper and cardboard, or ready-made components pulled together to allow evaluation, while as design progresses, they become more polished, compact, and robust so that they resemble the final product.

Broadly speaking, the design process may start from two distinct situations: when starting from scratch or when modifying an existing product. Much of design comes from the latter, and it is tempting to think that additional features can be added, or existing ones tweaked, without extensive investigation, prototyping, or evaluation. Although prototyping and evaluation activities can be reduced if changes are not significant, they are still valuable and should not be skipped.

In Chapter 10, we discussed some ways to identify user needs and establish requirements. In this chapter, we look at the activities involved in progressing a set of requirements through the cycles of prototyping to construction. We begin by explaining the role and techniques of prototyping and then explain how prototypes may be used in the design process. We end with an exploration of physical computing and software development kits (SDKs) that provide a basis for construction.