Semtech Corporation
Water-rejection proximity detector and method

Abstract:

A proximity sensor, and a portable device equipped therewith, with at least two superposed sense electrodes, one partially screening the other. By reading the capacity first of one electrode, then of the other, while setting the potential of the counter-electrode either to ground or to guard, the sensor of the invention discriminates between a body part, or another electrically equivalent object, and water drops at closer distance.