Occupant detection and classification system

A system for detecting an occupant in a vehicle seat, comprising:

• a sensing electrode located in a seat bottom of a vehicle seat;
• a shield electrode located in the vehicle seat below the sensing electrode;
• a sensing circuit operatively coupled to the sensing electrode and the shield electrode;
• a controller operatively coupled to the sensing circuit, wherein the controller operates to configure the sensing circuit to apply a shield current to the shield electrode and a sensing current to the sensing electrode;
• and
• wherein the controller is configured to detect the presence of an object in the seat by detecting a measure of the force applied to the seat by the object based on the impedance between the sensing electrode and the shield electrode;
• wherein the controller is configured to detect the presence of an object in the seat by comparing a measure of the quadrature component of the sensing current to a threshold wherein the measure is adjusted by an offset value that varies based on a value of a non-volatile counter.

A method of detecting an occupant in a vehicle seat comprising the steps of:

• providing a sensing electrode located in the seat;
• providing a current to the sensing electrode;
• measuring a quadrature components of the current provided to the sensing electrode;
• detecting and classifying the occupant in the seat by comparing a measure of the quadrature component of the current provided to the sensing electrode to a threshold;
• and
• wherein the measure is adjusted by an offset value that varies based on a value of a non-volatile counter.