A keyboard in the palm of your hand

It's not unusual these days to see virtual keyboards on the touch screens of portable devices like tablets and phones. These devices lack a physical keyboard but make up for it by displaying a picture of one on the screen and letting the user tap away on that.

But virtual keyboards are not just constrained to the screen. Today almost anything can become a keyboard – from a table top to the palm of your hand.

Korean company Celluon has been developing virtual keyboards for several years and their latest product is the Magic Cube, a small box that fits in your hand yet provides a full-size keyboard when needed.

Switch it on, sit it on a desk and it projects an image of a keyboard on to the surface in front of it. Tap the virtual keys and the corresponding characters are communicated wirelessly to any compatible device, from a laptop to a smartphone.

The principles involved are very simple. The projection of the keyboard is just that – made by a tiny projector at the top of the box. At the bottom of the box beams of infrared light are emitted just above the surface of the desk. As your fingers tap the surface they cut through these beams which are reflected up to a camera in the middle of the box. The camera sees the reflection and works out from its position which key you have "pressed".

Though the Magic Cube is clever it is essentially just a very portable replacement for a real keyboard.

More radical possibilities are on the horizon. Microsoft researchers Hrvoje Benko and Andrew Wilson, along with Chris Harrison of Carnegie Mellon University in the United States, recently showed off a system they call OmniTouch, which turns any surface into a touch screen.

OmniTouch is made up of a shoulder-mounted projector and depth-sensing camera combination. The projector displays interactive images on any nearby surface – a wall, a table, a pad or even parts of the user's body. The camera tracks the user's fingers, working out where and when they touch other objects.

Putting it all together allows the user to, for example, dial a phone number on a keypad displayed on the palm of their hand, or draw projected pictures on an ordinary paper pad.

Pretty much anything, in fact, that you can do with an ordinary touch-sensitive display, except that the display itself can be any suitable surface.

We take it for granted that the size of portable devices is a compromise between compactness and usability. But if the display and controls need not be physically part of the device, all bets are off. It's too early to tell whether systems like OmniTouch will take off. But in a few years they may virtually replace their physical counterparts in many situations, in more ways than one.