Piezoelectric vibration measuring sensor and accelerometer used for bed monitoring system

Abstract

This paper presents a multiple sensor system to predict behavior patterns that occur when patients leave their beds. We originally developed a vibration bolt sensor using a piezoelectric cable and a pillow sensor using an accelerometer. Existing sensors such as clip sensors and mat sensors require restraint of patients. Moreover, these sensors present privacy problems. The features of our sensors are that they require no power supply or patient restraint. We evaluated our system using a basic experiment to predict seven behavior patterns. We obtained a result of predicted behavior patterns related to bed-leaving using only two sensors installed on a bed. Especially, our system can correctly detect behavior patterns of lateral sitting, which is a position that occurs when a patient tries to leave from the bed, and terminal sitting, which is the position immediately before bed-leaving. They were discerned from other behavior patterns.