A substrate suitable for incorporation into an absorbent article for automatic detection of wetness events therein, the substrate comprising a first surface capable of being arranged proximal to a body facing side of the absorbent article and a second surface opposite said first surface and capable of being arranged proximal to a garment facing side of said absorbent article, said substrate comprising a plurality of sensor tracks disposed on said first surface and said sensor tracks comprising: at least one central track extending parallel to a length of the substrate and parallel to a longitudinal axis crossing a first end and a second end of the substrate； at least two side tracks extending parallel to the central track and oppositely arranged such that the central track extends therebetween； and wetness sensing tracks extending outboard of said two side tracks, wherein said central track, said side tracks, and said wetness sensing tracks are in electrical communication via one or more shortening elements positioned proximal to said second end and distal from said first end, and wherein the substrate is connectable to a clip-on data processing module at a position proximal to said first end and distal from said shortening elements such to form a closed electrical circuit, typically for measuring resistance and/or capacitance therethrough. In an embodiment said substrate consists of a liquid impermeable backsheet, preferably a breathable liquid impermeable backsheet.
