Fluid input devices and fluid dynamics-based human-machine interaction

We propose a highly expressive input device having keys that each generate an acoustic sound or similar disturbance when struck, rubbed, or hit in various ways. A separate acoustic pickup is used for each key, and these pickups are connected to a computer having an array of analog inputs. Non-binary, continuous sensitivity allows a smooth ("fluid") range of control. We describe three embodiments of the input device, one that works in each of the 3 states-of-matter: solid, liquid, and gas. These use (respectively) geophones, hydrophones, and microphones as the pickup devices. When used with liquid or gas, the device becomes a fluid-dynamic user-interface, comprising an array of fluid flows that are sensitive to touch. Sounds are produced by a Karman vortex street generated across a separate shedder bar, shedder orifice, or other sound producing device for each finger hole. Data is entered by covering the holes in various ways. This gives highly intricate variations in each keystroke by using a concept we call "finger embouchure", akin to the embouchure expression imparted to a flute by the shape of a player´s mouth. We also present the concept of an array of frequency shifters, which we refer to as a shifterbank. The shifterbank helps in providing meaningful audible feedback for the data input, as well as helping in one very specialized form of data entry, namely musical composition.