New Wetness Sensor with an Energy Storage Structure and a Novel Battery-Less Wetness Detection System

Abstract

To develop a textile-based wetness detection system that operates without batteries, we created a wetness sensor with an energy storage structure that generates electric power when water comes into contact with electrodes having different redox potentials. Electrodes were prepared by coating a silver current collector layer and an active material layer of silver oxide or zinc on a non-woven fabric and then sewing on a cloth substrate in a comb-like shape using a conductive thread. The output characteristic values of the textile-based sensor were higher than one with the same structure produced by printing on a plastic substrate. A wireless communication IC could be operated by connecting three sensors in series. Thus, we realized a "battery-less textile-based wetness detection system" that can detect a wet fabric, such as, for example, a wet seat.