Abstract: The present invention is directed towards a sensor including, inter alia, a body having first and second spaced-apart apertures, the first aperture having a shape producing an audible noise upon a fluid passing therethrough; a piston positioned within the body; and a chamber having an additional fluid disposed therein, with a volume of the additional fluid placing the piston between first and second positions, the first position impeding the first volume of fluid and the second position allowing the first volume of fluid to pass through the first aperture.