User-interfaces based on the water-hammer effect: water-hammer piano as an interactive percussion surface

Water hammer, a well known phenomenon occurring in water pipes and plumbing fixtures, is generally considered destructive and undesirable. We propose the use of water hammer for a musical instrument akin to hammered percussion instruments like hammered dulcimer, piano, etc. In one embodiment, the instrument comprises an array of mouths each for being struck with the open palm or fingers, each mouth connected to a separate hydraulic resonator. In another embodiment, we use a basin or pool of water as a multitouch user-interface where sounds made by water are acoustically sensed by an array of hydrophones (underwater listening devices). Using water itself as a touch surface creates a fun and playful user interface medium that captures the fluidity of the water's ebb and flow.