Urinary incontinence is one of the symptoms that aging people often experience. In an effort to improve their living conditions, we demonstrate a smart diaper system that was developed for incontinence patients. The flexible electrode embedded in the diaper intermittently supplied power to a 433MHz transmitter using a boost circuit and was used for detecting urine volume in a diaper. Our intelligent diaper design enabled signals to be received within 20 meters and Bluetooth signals to be sent to caregivers within 70 meters. The application developed for this system was installed in the caregiver\'s mobile phone, which can receive Bluetooth data, display urine volume in the diaper and prompt the diaper change timing.