Over the years, the reaction to my job title "mobile interaction designer" has migrated from blank stares. Still only about half the time does anyone have any idea what I mean. And if they do, they almost always assume it's designing mobile phones, or apps for them.

Occasionally, someone asks if we also design games for the Nintendo DS, or make maps for GPS navigation, or do work for some other sort of device. Has the definition of mobile changed? This is a list of the types of things I looked at to find and validate these patterns:

• Mobile smartphones
• Mobile featurephones
• Mobile network access points (Aircards)
• MIDs
• Tablets
• eReaders
• Media players
• Image viewers and digital picture frames
• Portable game systems
• Remote controls
• Hand-held navigation devices
• Portable scanners
• Cameras and other capture devices
• Printers, scanners, copiers and mopiers (MFDs)
• Kiosks
• Wearable computers
• Telematics, and vehicle-mounted devices
• Industrial automation
• Portable surveying, measuring and metering equipment

I am sure a lot of others were left out. While these share many characteristics, many are not particularly mobile. Kiosks are by definition bolted to the ground, for example. And no one much thinks of a camera as similar to a phone.

So my first answer is that "mobile" is not a useful word, and that this book addresses a lot of these devices. Their design can be informed by the mobile patterns in this book and elsewhere. The ubiquity of mobiles also may mean that employing these as universal patterns is a good thing, as users may require less training when using interfaces to which they are accustomed. If you design cameras, or printers, you should be paying attention to the state of the art in mobile.

Really finding a definition

I didn't come up with this answer out of the blue, or just trust instinct. Instead, years of work, discussion, writing, and arguing led to some principles of "what is mobile."

I like to think of the evolution of mobile telephony as being in four eras:

1. Voice
2. Paging and Text
3. Pervasive network connectivity
4. General computing devices

Yes, this leaves out a lot of interesting devices that are on the big list above. The Gameboy and GPS receivers pre-date what most of us would call mobile phones by several years. But mobile telephony is what changed the world, and ushered in all this, so it's a good anchor point.

If you consider a current mobile phone as a generally "4th era" device what you find is they are:

• Small - Small enough to carry with you all the time. Preferably in a pocket.
• Portable - Battery powered and otherwise independent of the world, so it doesn't have to be plugged in or attended to regularly.
• Connected - Wirelessly. Not attached to the wall or connected only when the user makes special effort. Whenever possible, connected in multiple ways, to both voice and data networks.
• Interactive - Inherently. Unlike a watch, or even most MP3 players, which are limited to display, playback and a small subset of interactions, more undirected actions can be taken, such as text entry and keyword search.
• Contextually-aware - The device (or services it is attached to) uses it's ability to understand the network to which it is attached, and it's other sensors to help the user get things done, and pre-emptively gather information.

With this many facets, it's easy to disregard any one, and still feel the device meets our needs. Strapping an iPad to a wall and calling it a kiosk simply removed the "portable" feature, so it's still a "mobile" device.

Consider the Wii, or X-Box Kinect instead. Though the display is not at all portable, they are at their core aware of user position, they change with the type of input being used, and the entire interface has been designed to support interaction via a game controller, or simply waving your arms at the screen. These meet the interactive criteria to be a "mobile" device.

Now take a Windows tablet PC. It has pen and touch input, can be quite small and portable, is networked, and has sensors. But I argue it is not mobile. It's not really connected, because it does so like a desktop, so you have to open dialogues and press buttons. It isn't usefully interactive, because you cannot use it on the go, but have to stop to use it. It's not contextually-aware, because the GPS, or camera, or accelerometers don't do much of anything by themselves.

What type of patterns we will cover

So, while this book does still focus on the classic answer, the mobile phone and especially the smartphone, similar interactions from kiosks to game stations to telematics, are also considered. In some cases, I'll even refer to these devices directly in the patterns.

The patterns are guidelines for implementing interaction design on these devices. So they talk about page-level components like scrollbars, display components like pop-ups, widgets like buttons, and input methods like keyboards.

But they also talk about things like the labels and lights for hardware keyboards. You might ask yourself why I do this? You can't influence it, after all. But you can. You can fail to implement correctly, and cause keyboard entry to fail. You can change scrollbar behavior, if there's a special case for your application. Increasingly, as HTML5 technologies roll out, mobile websites can take advantage of interesting interactive features.

And you might even be working on a device operating system. More likely, the GUI layer on top of an existing OS, but I have on multiple occasions. There are many, many devices, and new classes still emerging. Overlays have migrated down to the point that end users may change the basic behavior of their handset. You may have to work in this space sooner than you think.

If not, then you still need to understand why certain OS level behaviors are standard, or should not be, so you can make informed decisions about your design.

Next: What is a Pattern?