Japanese technology titan NEC has unveiled a gadget that allows users to control their TV, mobile phone or tablet computer using a virtual input device.

The company said a camera that recognises three-dimensional shapes and their movements will combine with a projector that could show the image of an input device -- such as a keyboard -- on almost any surface.

Users can then gesture at the projected image to move an electronic file or play a video, with the movement of their hand relayed back to the device they want to control.

"With the recent expansion of cloud-based services, information terminals have become increasingly diversified, ranging from PCs to smartphones and tablet devices," a company statement said Tuesday.

"However, the presentation of information is limited to the displays on such devices, and operation needs to be performed with the use of an input device such as a remote control, mouse or touchscreen.

"Using this technology, multiple devices can be controlled based on a user's movements, without the use of an input device, producing interfaces that boast more natural interaction."

NEC said it hoped to develop the technology so that it could be used with devices that do not have displays, including lights and air conditioners, raising the prospect of a home controlled largely by waving.