US Patent 9204816 Method and system for determining body impedance

A method and system for determining a body impedance (Zbody) of a user are disclosed. The method comprises coupling a sensor device to the user, wherein the sensor device includes at least a first and a second electrode. The method includes applying a voltage signal (Vin) through a first impedance (Zin1) to the first electrode and through a second impedance (Zin2) to the second electrode to produce an output signal. The method includes measuring a differential voltage (Vbody) across the first and second electrodes and calculating the body impedance (Zbody) using the measured differential voltage (Vbody), the voltage signal (Vin), the first impedance (Zin1), and the second impedance (Zin2).