US Patent 7806882 Tampon saturation monitoring system

A tampon that has a sensor and a signal line that peripherally connects the sensor with a peripheral signal processor. The sensor provides a blood wetting signal in response to a progressing blood saturation boundary in the tampon. The signal may be resistive, capacitive or optic. The simple sensor has two proximal signal terminals separated by a fluid responsive medium in wetting communication with the tampon's body. The tampon may be removed by use of the signal line. From signal timing and/or signal gradient the processor may predict when the tampon needs to be changed.