Self-powered wireless urinary-incontinence sensor determines time for diaper change from spacing between sensing signals

A self-powered wireless urinary-incontinence sensor system composed of a wireless sensor and a receiver has been developed that determines the time for a diaper change. To determine if the amount of urine in the diaper is large enough to require a change of diapers, the number of incidents and the amount of urine per incident are required. The urine-activated battery consists of two long flexible electrodes, one of activated carbon and the other of aluminum. They are placed under a piece of absorbent material, and this unit is embedded in a diaper. A prototype urinary-incontinence sensor system with the battery determined the amount of urine in a diaper from the spacing between the sensing signals with a resolution of 40 cm
³
and determined the time for a diaper change.