Abstract: A self-compensating fluid level sensor is described, including a dual array of capacitive sensors on a dielectric substrate, the dual array of sensors forming multiple sensor pairs. Multiple signal detection circuits including comparators are configured to compare the capacitance of a first sensor pair with a second sensor pair. The internal capacitance comparisons allow the fluid level sensor to compensate for variations in the dielectric of the fluid being measured, as well as for manufacturing and materials variations that affect capacitive sensing. The passive level sensor also provides a platform for providing additional circuitry for providing additional information regarding the liquid, such as liquid composition.
Type:
Grant
Filed:
September 8, 2000
Date of Patent:
June 17, 2003
Assignees:
Labarge, Inc., GDM, Inc.
Inventors:
Steven M. Vogel, John A. Sturm, Andrew M. Matulek, Clayton R. Mason, William C. Wolffe