Gesture Sensing
Compact magnetometers, accelerometers, and gyroscopes make it possible to track the movement of a device. Using both Nintendo's Wii controller and the iPhone, users can control games and applications by physically maneuvering each device through the air. Similarly, it's possible to pause and play music on Nokia's 6600 cell phone simply by tapping the device twice.

New mobile applications are also starting to tap into this trend. Shut Up, for example, lets Nokia users silence their phone by simply turning it face down. Another app, called nAlertMe, uses a 3-D gestural passcode to prevent the device from being stolen. The handset will sound a shrill alarm if the user doesn't move the device in a predefined pattern in midair to switch it on.

The next step in gesture recognition is to enable computers to better recognize hand and body movements visually. Sony's Eye showed that simple movements can be recognized relatively easily. Tracking more complicated 3-D movements in irregular lighting is more difficult, however. Startups, including Xtr3D, based in Israel, and Soft Kinetic, based in Belgium, are developing computer vision software that uses infrared for whole-body-sensing gaming applications.

Oblong, a startup based in Los Angeles, has developed a "spatial operating system" that recognizes gestural commands, provided the user wears a pair of special gloves.

Force Feedback
A field of research called haptics explores ways that technology can manipulate our sense of touch. Some game controllers already vibrate with an on-screen impact, and similarly, some cell phones shake when switched to silent.

More specialized haptic controllers include the PHANTOM, made by SensAble, based in Woburn, MA. These devices are already used for 3-D design and medical training--for example, allowing a surgeon to practice a complex procedure using a simulation that not only looks, but also feels, realistic.

Haptics could soon add another dimension to touch screens too: by better simulating the feeling of clicking a button when an icon is touched. Vincent Hayward, a leading expert in the field, at McGill University, in Montreal, Canada, has demonstrated how to generate different sensations associated with different icons on a "haptic button". In the long term, Hayward believes that it will even be possible to use haptics to simulate the sensation of textures on a screen.

Voice Recognition
Speech recognition has always struggled to shake off a reputation for being sluggish, awkward, and, all too often, inaccurate. The technology has only really taken off in specialist areas where a constrained and narrow subset of language is employed or where users are willing to invest the time needed to train a system to recognize their voice.

This is now changing. As computers become more powerful and parsing algorithms smarter, speech recognition will continue to improve, says Robert Weidmen, VP of marketing for Nuance, the firm that makes Dragon Naturally Speaking.

Last year, Google launched a voice search app for the iPhone, allowing users to search without pressing any buttons. Another iPhone application, called Vlingo, can be used to control the device in other ways: in addition to searching, a user can dictate text messages and e-mails, or update his or her status on Facebook with a few simple commands. In the past, the challenge has been adding enough processing power for a cell phone. Now, however, faster data-transfer speeds mean that it's possible to use remote servers to seamlessly handle the number crunching required.