Researchers have created a "touchscreen" for your bathtub. With only a Kinect sensor and a projector, AquaTop display facilitates interacting with virtual objects using just your hands. In order to function properly, the system requires you add some bath salts to your tub, which will turn the water opaque and prevent the camera from picking up false inputs. As a proof of concept, the team at Tokyo's University of Electro-Communications Koike Laboratory have created a number of demos that utilize some innovative gestures.

Most of the demos take the form of basic games, allowing you to use two hands to create and channel a ball of energy towards an enemy object, or play a game of soccer by pushing waves of water in the direction of your opponent's goal. There are also other games that involve using a single finger or a pair of digits to flick objects around, and a demo that lets you reorganize photos by scooping water up into your palms and placing it somewhere else. Perhaps the most innovative gesture is one that lets you erase objects by pulling them into the water.

Of course, the AquaTop is just a concept: the likelihood of a system using a large projector and Kinect camera being installed in a house is very low. The demo also uses jets that send droplets of water scattering into air in time with "on-screen" events, which isn't particularly practical. But as this kind of technology slims down and becomes even more prevalent, we could see our households become interactive. It's interesting to see work being carried out on how we'll interact with these new surfaces.