The Koike Lab at the University of Electro-Communications in Japan has demonstrated the use of a bathwater-based touchscreen interactive display. The system projects a display onto the surface of your bathwater from above and uses a Microsoft Kinect to detect movement and user interaction with the UI imagery. The AquaTop enables gestures and interactions which are unique to fluid displays where users can pick up and move a handful of water (corresponding to an item in the UI) and also interact with the water surface from above, or from below, with prods, multitouch and gestures.
Yashushi Matoba explained the utility value of the bathwater surface display; “For example, if you point to an object with one finger from below, you can move the object freely. If you point with two fingers, you can enlarge, shrink, or rotate the object. If you use five fingers, and pull them through the water, that gesture can be used as a delete or pause command.” Matoba said he was particularly fond of another unique fluid display gesture where a user can pick up a section of the display with scooped hands and move it to another area of the bath/UI.
The new AquaTop display is seen by Matoba as a system which is more intuitive in many ways than systems that have come before it. “I think even young children can understand this, just by looking at it, without any explanation in words. If I say, “put something in this box,” ordinarily, you'd pick an object up and drop it in. Here, you can do the same thing on this water surface, by scooping something up with both hands and dropping it over a folder,” he said. With development and further refinements it is seen that the AquaTop could “lead to a computer that people can see how to use, without reading a manual”. However Matoba admits that it’s still a bit tricky to use the AquaTop, compared to the ubiquitous mouse, for some interactions.
Koike Labs also demonstrated a new game using the AquaTop system. While in the bath a gamer throws projected shuriken at a projected jellyfish image at the other end of the bath, to destroy it. Speakers under the water cause the surface to ‘explode’ like a fountain. Such feedback can be a lot stronger in water than air as pressure waves don’t attenuate as much over distance. Thus a properly directed underwater speaker feedback system could provide a very powerful “tactile stimulus to any part of the body” during gameplay.