Patent ID: 7802471
Filing Date: 2010-09-28
Classification: G01F

Abstract:
1. A liquid level sensor device comprising: a liquid level sensor element, the liquid level sensor element including (i) at least two sets of N conductive electrodes disposed parallel to one another in an array, where N represents an integer number of conductive electrodes in an individual set of conductive electrodes, the liquid level sensor element further including (ii) M sense lines, where M represents an integer number of sense lines greater than or equal to the number of conductive electrodes N, each of the M sense lines further being coupled to select ones of the N conductive electrodes of the at least two sets of conductive electrodes to form a number of L sets of parallel coupled conductive electrodes, where L equals M; a capacitance-to-voltage converter coupled to the M sense lines of the liquid level sensor element for periodically measuring a capacitance of the L sets of parallel coupled conductive electrodes; and a controller coupled to the capacitance-to-voltage converter, the controller being configured to (a) establish (a)(i) initial measured baseline capacitance values for each of the L sets of parallel coupled conductive electrodes and (a)(ii) an initial liquid level height value, the controller further configured to (b) detect transitions in the measured capacitance of the L sets of parallel coupled conductive electrodes.