Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences


UC Berkeley


2008 Research Summary

A Human Health Monitoring System Using Fuzzy Logic

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Yutaka Hata and Hiroshi Nakajima

We have developed a heart pulse monitoring system using fuzzy logic. It consists of an air pressure sensor and an ultrasonic oscillosensor system. The air pressure sensor system consists of an air cushion of 175 mm × 780 mm and an ultrasensitive pneumatic sensor. This sensor detects a pressure change generated by the vibration of vital activity. The ultrasonic oscillosensor has the cylindrical tank of 26 mm (diameter) × 10 mm (height) filled with water, and an ultrasonic probe (central frequency: 2 MHz) set to the bottom of tank. The ultrasonic wave is transmitted from the ultrasonic probe, and the probe receives the echo from a water surface. Thus, it can obtain the low-frequency vibration of 10 Hz or less.

The ultrasonic oscillosensor system unconsciously detects various actions of a human by placing it under a bed frame, and it determines several human actions aided by fuzzy inference. The air pressure sensor system non-evasively detects heart pulses aided by a frame of the fuzzy expert system when placed into a mattress in a bed. Consequently, the system of two sensor systems can determine whether or not a human is in bed, and it provides the heart pulse with high accuracy and robustness.

Y. Hata, Y. Kamozaki, T. Sawayama, K. Taniguchi, and H. Nakajima, "A Heart Pulse Monitoring System by Air Pressure and Ultrasonic Sensor Systems," Proc. IEEE System of Systems Engineering, CD-ROM, 2007.