The touch interface is only just beginning to make the transition from smartphones and tablets to PCs, thanks in part to Windows 8. But the industry is already working on other ways to interact with computers and mobile devices. Just as the popularity of smartphones and tablets paved the way for touch on PCs, the successful introduction of motion controls on game consoles — the Nintendo Wii, Microsoft Kinect, and Sony PlayStation Move — has created an opportunity for more novel user interfaces.

Perhaps the most interesting — and most hyped — is the Leap Motion Controller. The company announced this week that the USB device, which adds motion controls to computers, will be available starting in May for $80. Leap Motion said the device, which is about the size of a flash drive, is significantly more accurate than a game console's motion controller. It works with Windows 7 and Windows 8 PCs and Macs, but it seems like a natural fit for the modern Windows 8 interface. No new technology can launch without its own app store, and Leap has one called Airspace. The company is already developing motion-controlled apps with several partners, including Autodesk, Corel (Painter), Disney Interactive, Double Fine Studios (Dischord, a music game), The Weather Channel, and ZeptoLab (Cut the Rope). The Leap Motion Controller has gotten some positive early feedback and I'm looking forward to trying it out.

At Mobile World Congress (MWC) this week, there were many demonstrations of new user interfaces. Intel posted a YouTube video showing some of its own demonstrations using motion control, and voice and facial recognition. SoftKinetic, a Belgium-based company that developed a 3D DepthSense camera for laptops and motion-control software, said it provided the technology behind not only Intel's Perceptual Computing demonstrations, but also smart TV demonstrations from YOUi Labs and Marvell.

Qualcomm announced a Snapdragon Voice Activation, a feature that it said will allow users to securely wake up a mobile device using a Snapdragon 800 processor in standby or airplane mode using only a custom voice command. The company said there are 55 Snapdragon 800-powered tablets and smartphones in development. A competing chipmaker, STMicroelectronics, demonstrated its Fingertip technology on a Nexus 7 tablet. The feature uses micro-electro-mechanical systems (MEMS) sensors to enable you to control a mobile device by hovering over it (within about 2 inches) without actually touching the glass.

At the TED conference, also this week, an MIT grad student showed a 3D interface he developed while working at Microsoft. The SpaceTop 3D interface uses a transparent display and two cameras to enable you to use your hands to interact with things on the screen as if they were physical objects. This one seems more like a science project — there are no plans for commercialization — but it is certainly interesting.

All of this is happening at the same time that innovation in the basic hardware — phablets, convertibles, and ultrabooks — is blurring the lines between PCs and mobile devices. Things are getting interesting in PCs precisely when interest in the PC is on the wane. Of course that is one of the reasons we are seeing so much experimentation. Competition has forced the hand of computer makers.

Whatever the reason, it seems likely that the PCs and tablets we are using only a couple years from now won't look the same or work the same as the ones we have today.