User understanding will improve over time with familiarity, but only if we, as
designers, help them with clear system images. We need to figure out what
complexity users will need to deal with, and where products and tools can be
simplified. As a general rule, if the task or activity the user wants to perform is
complex or requires a high level of skill, it’s appropriate for the user to engage
with that complexity. Or perhaps it’s a job for a professional. If the task or
activity can be expressed simply but the technology is complicated, there’s a
good case for designing around a simplified mental model.
We don’t yet know what that looks like for IoT. For starters, if you need to
explain to the user that part of the system is not working, it’s important to
explain why and what this means. For example, if you are alerting them that
the security alarm has lost internet connectivity, you might choose to tell them
that the cameras and alarm sounder are still active but that they will not
receive alerts. Or if the user is travelling in a different timezone, you might
want to show the current time at home on the heating control app, to indicate
that schedule changes are based on the local timezone of the controller, not
where they are now.
Composition
Patterns of composition
Composition refers to the way the functionality of a service – especially the
user-facing functionality - is distributed across devices.
Good composition distributes functionality between devices to make the most
of the capabilities of each device. Designers should take into account the
context in which each device will be used, and what users expect each to do.
There are some common patterns to composition. Web services delivered
across smartphones, desktops, tablets and connected TVs are often multi-
channel. Each device provides the same, or very similar, functionality (in other
words, there is a high level of redundancy between devices. Kindle, Netflix
(see figure 9.12) , BBC iPlayer, Facebook and eBay are all examples. Devices
with small screens or limited input capabilities may only provide a subset of
key functionality. But each device offers a similar basic experience of the
service. Many users won’t own or use all the possible devices on which the
service could be used and this doesn’t matter. It’s perfectly possible to use the
service via a single device and still have a good experience.