Occupant detection and classification system

A system for detecting an occupant in a vehicle comprising:

• a sensing electrode mountable 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 into four circuit configurations;
• and wherein in each of the four circuit configurations the sensing electrode and the shield electrode are electrically coupled to the sensing circuit, wherein the controller sends a signal to the sensing circuit, and measures a plurality of current measurements, each current measurement corresponding to one of the four circuit configurations,
• wherein the plurality of current measurements are used by the controller to determine the presence of an object on the vehicle seat and to classify the object;
• and
• wherein the sensing circuit comprises:
• a first switch configured to change an amplitude of the signal between a first amplitude and a second amplitude, the first amplitude and the second amplitude being greater than zero, and
• a second switch configured introduce a known impedance in the sensing circuit,
• wherein the first switch and second switch are opened and closed by the controller to configure the sensing circuit into the four circuit configurations.