Patent ID: 8896326

Claim:
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.