A hydraulophone is a tonal acoustic musical instrument played by direct physical contact with water (sometimes other fluids) where sound is generated or affected hydraulically. Typically, sound is produced by the same hydraulic fluid in contact with the player's fingers. The term also refers to an acoustic sound-producing mechanism used as an interface or input device involving the monitoring of fluid flow. Examples include hydraulophones for fluid-flow monitoring and measurement applications, such as building automation, equipment monitoring, and the like (for example, determining which faucet or toilet in a building is operating and how much water it is consuming). The hydraulophone in the first sense was invented and named by Steve Mann, and has been used as a sensory exploration device