Patent ID: 8646860

Claim:
A fluid level sensor for measuring a height of a fluid comprising: a container having at least one wall that forms a volume for containing a fluid; a plurality of piezoelectric sensors arranged along the at least one wall of the container to interact with the fluid within the volume, two of the piezoelectric sensors being positioned to enable fluid in the volume to cover simultaneously a portion, but not all, of a surface area of a first piezoelectric sensor of the two piezoelectric sensors and a portion, but not all, of a surface area of a second piezoelectric sensor of the two piezoelectric sensors, the portion of the surface area of the first piezoelectric sensor covered by the fluid being larger than the portion of the surface area of the second piezoelectric sensor covered by the fluid; and a pair of conductors operatively connected to each piezoelectric sensor, the conductors configured to conduct electrical signals to and from each piezoelectric sensor.