a moisture sensor includes a pair of electrode plates separated by a moisture absorbent material that forms the dielectric of a capacitive sensor . as the absorbent dielectric material absorbs moisture , such as perspiration , the capacitance of the sensor changes reflecting a quantitative measure of perspiration absorbed . the sensor can be stabilized by capacitively coupling the dielectric material to the skin of the user to improve sensor stability and noise rejection . the sensor can include a capacitive sensing integrated circuit that measures the capacitance of the sensor in close proximity to the electrodes to limit the introduction of noise .