Water-sensitive urination detection system robust to body fluid and posture

In this study, we propose a water-sensitive urination detection system that detects urination not by physical disconnection of an ultra-high-frequency tag, as in the conventional method, but by a decrease in communication strength due to the influence of water during urination. The tag is attached to the outside of the diaper and keeps communicating with the antenna under the mattress. False urination detection due to changes in posture was addressed using a three-dimensional tag arrangement and an algorithm that identifies when the user turns over. System evaluation tests were conducted. The effectiveness of the system was demonstrated by measuring the urination detection rate using a simulated urination test with a tube. The detection algorithm was used both before and after the user turned over. The results show that the system can detect turning over with high accuracy and that the possibility of false detection is low. These findings suggest that a water-sensitive urination detection system based on the moisture-induced attenuation of communication strength can be used for urination detection.