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

This next part might be a little boring, so if you are just interested in the patterns and not why they exist, just skip to the next section.

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.

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.

So, if we deconstruct this,

• Contextually-aware
• Naturally-interactive
• Constrained interface

If we use this definition, then pretty much all mobile phones are included.

And some other devices in the "MID" (mobile internet device) range, such as the iPod Touch and the recent spate of mobile tablets. So, "mobile" is also:

• Things very like mobile phones, but without the mobile radio,
• and things very like mobile phones, but with different form factors.

But my device feels mobile also

But what if you are one of those folks who glues an iPad to down, to make it an ad hoc kiosk? It's no longer small, it's not portable anymore, so what is it?

Well, obviously it's a mobile device still. And if so, then the gut feeling is that so are GPS receivers, portable game systems, maybe even TV game systems. And then why not DVRs, and so on.

But certainly not TV video programming. And there are Windows tablets hardly bigger than many of the new iOS and Android tablets, which are clearly not particularly mobile-like, even if some of them are used on small screens, and in unusual environments.

So what makes some "mobile" and some just "not"? From a broader point of view, without as much focus on the hardware but the interaction and method of use, it seems to be:

• Contextually-aware
• Naturally-interactive
• Constrained interface

Take a Windows tablet PC, for example. It has pen input, but spottily implemented; text entry works well, but other controls are still in desktop-PC mode, so are hard to use. Many have GPS, cameras, audio input or even accelerometers. But they are not integrated with the OS, or the general user interaction; special software is required to use them, and in general the device doesn't know which way you are facing, where you are, or even react to whether it is day or night.

So, simply making a device small, connected and battery powered doesn't make it mobile because its not contextually-ware or naturally-interactive.

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.

The "constrained interface" bullet above might seem to be there just so we can arbitrarily say "mobile is small." However, it's as organically derived from user behaviors with these devices as the other bullets are. For example, if you put a real, full-size keyboard on a mobile device, the keyboard acts like a desktop computer, and suddenly all text input follows desktop computing patterns, not mobile patterns. The method by which the user interacts is the guiding principle in this defintion.

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, these may even be referred to in the pattern language.

So, which kind of devices are these?

In the end, a lot of devices have at least some of these attributes, and their design can be informed by mobile patterns. 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.

A non-inclusive list of device and use categories that were considered during writing, or which are specifically mentioned in the book are:

• 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

Aside from the logical reasoning outlined above, we have worked on many of these categories of products -- at least a little -- and have had good results applying these principles to the design of interfaces for these devices.

So, what patterns are covered here?

These are patterns for interaction design on these devices. To that end, they expand to talk about buttons, accelerometers, cameras, lights and other hardware facets. But all within the context of on-screen interaction design. Or, the equivalent of "on-screen" for audio, annunciator lights, and haptics.

Likewise, these focus on behaviors that can be changed, so mostly address generalized interactive elements that can be used for applications and websites. Keyboard design, dialers and other parts of the interface that are only changeable by manufacturers or operators (or certain hacking shops) are included as well.

These are included mostly for understanding, so every designer working on their small part has an idea what the immutable components are for, and how they should work. But also because there are a lot of handsets being designed, there are a lot of operators and the growth should mean more and more room for these devices to be designed and configured in the future.

XXXXXX However, if you are used to very tactical books, about how to get the right reflection on your app icon, this might seem to miss the point. That's because it's not a book for today, but for yesterday and tomorrow.

When I started working in mobile full time, the word "app" was not rolling off the tongues of everyone, and the mobile web was something of an embarrassment. In 18 months, who knows what the world will bring?

So parts of this book will bore you. Web designers need to know some, but can implement very few of the patterns, though more all the time as HTML5 comes to fruition. App developers can implement more, depending on what sort of app, and what level of device integration they get. And on what platform. And there are a lot more device and OS designers than you think. I can think of around 20 eReaders alone. Touchscreen clocks, and interactive cars? There are a lot of people working on these systems, will be more tomorrow, and the lines will begin to blur soon over web, app, os. So we did not label what each pattern applies to. You will figure it out, and tomorrow it will all change.

What Operating Systems does it focus on?

I've tried to make this book OS agnostic. It covers

An important point is that a lot of the interaction associated with a mobile OS is actually about the GUI. Operators re-skin their featurephone offerings, manufacturers reskin smartphone OS's, and you can apply your own to some of these. This might be expected to expand in the future, at least for some systems

ALSO: Be sure to mention 1) OS means GUI. The modding community on Android, not to mention the ability to skin for operators, implies that very soon deeply embedded features may be under control of third-party applications. Etc.

And the OS for a web app is in many ways the Web, and the browser...

2) You can still mess this up. Some OS's allow you to override (or mis-apply) keyboard functions, scrollbars, annunciator rows and more. You need to know why these exist, and how to use them correctly in everyday application design.

Next: What is a Pattern?