the user is in at home e.g. to turn the lights on and off, a smartphone could be
used via Bluetooth LE connections, but will only be accurate if the user carries
it with them at all times.
Do users have set expectations of devices?
Users may expect certain devices to conform to familiar form factors, or
provide familiar functionality. For example, they are likely to expect a heating
controller to have some way of turning the heating on, or up.
How do you balance c ost, upgradeability and flexibility?
User interface components, such as screens and buttons, are expensive to add
to embedded devices. You may therefore decide to limit interactions on the
embedded devices themselves and do most of the interaction “heavy lifting”
via mobile apps or web interfaces.
It can be difficult to add new features to devices that are already out in the
field, especially if this requires modifications to the interface. Again,
offloading interactions to smartphone and web apps, which can be modified
relatively cheaply and quickly, may make sense.
What connectivity and power issues do you need to consider?
It may also be simpler to handle information processing in the cloud, as with
the Withings scales and fitness trackers, which simply take readings, display
them in real-t ime, but handle all other functionality in the online service. A
weight and fitness service can handle temporary losses of connectivity
gracefully, by storing data locally and syncing when the connection is
available again. However, for other types of service this will not be acceptable,
e.g. where safety or security is at stake. If a monitoring system for an elderly
person loses connectivity, it might be acceptable for motion sensor data to be
temporarily unavailable to the carer, as long as it is clear that connectivity has
been lost and live data is not available. However, it would be completely
unacceptable for the elderly person to be unable to use their emergency alarm
during this time: the alarm should be able to fall back to using another form of
connectivity.
In other words, the designer has to make an informed call on which tasks need
to be available in different conditions: offline? With no power? Does the