Patent ID: 7373817

Claim:
A fluid level sensor apparatus for detecting a moving fluid level and capable of activating a controlled device, said fluid level sensor apparatus comprising: a fluid-proof barrier having first and second opposite surfaces, wherein said first barrier surface is exposed to the fluid; a fluid-proof housing enclosing a cavity proximate said fluid-proof barrier, said fluid-proof housing being adapted for submersion in said fluid whose level is to be detected; a dielectric substrate sealed within said cavity; at least one sensor disposed on said dielectric substrate, each said at least one sensor comprising: a first thin, conductive sensing electrode in a closed, continuous geometric form having an area which affords substantial coverage by fluid contact with said barrier; a second thin, conductive electrode in a spaced, coplanar and substantially surrounding relationship to said first sensing electrode; and an active electrical component proximate said first and second sensing electrodes and electrically coupled to said first and second sensing electrodes, such that fluid contact with said barrier activates the controlled device.