Real-time and continuous monitoring of physiological signals is essential for mobile health (m-Health) for efficient and convenient medical services. An active pulse sensing system that can detect the weak vibration patterns of the human radial artery has been constructed with a sandwich-structure piezoelectret structure. The high precision and stability of the system result in possible medical assessment applications, including the capability to identify common heart problems (such as arrhythmia); the feasibility to conduct pulse palpation measurements similar to well-trained doctors in Traditional Chinese Medicine; and the possibility to measure and read blood pressure. Specifically, the initial study in combination with the approximate entropy (Ap En) algorithm show promising results in detecting human health conditions. The pulse signals of 26 volunteers were measured and analyzed to show that the Ap En value of 0.1 can be set as a threshold for judging and predicting human health status.

Professor Liwei Lin received PhD degree from the University of California, Berkeley, in 1993. He joined the University of California at Berkeley in 1999 and is now Professor at the Mechanical Engineering Department and Co-Director at Berkeley Sensor and Actuator Center (BSAC), an NSF/Industry/University research cooperative center. His research interests are in design, modeling and fabrication of micro/nano structures, sensors and actuators as well as mechanical issues in micro/nano systems including heat transfer, solid/fluid mechanics and dynamics. Dr. Lin is the recipient of the 1998 NSF CAREER Award for research in MEMS Packaging and the 1999 ASME Journal of Heat Transfer best paper award for his work on micro scale bubble formation. He led the effort to establish the MEMS division in ASME and served as the founding Chairman of the Executive Committee from 2004~2005. He is an ASME Fellow and has 20 issued US patents in the area of MEMS. He was the general co-chair of the 24th international conference on Micro Electro Mechanical Systems at Cancun, Mexico. Currently, he serves as a subject editor for the IEEE/ASME Journal of Microelectromechanical Systems.

Smart phones, cars, and wearable activity trackers are just a few examples of products with sensors based on technologies pioneered at the Berkeley Sensor & Actuator Center, a Graduated NSF Industry/University Cooperative Research Center for Micro/Nanoelectromechanical Sensors & Systems (MEMS/NEMS). New research at BSAC will have even greater impacts on consumer, industrial, and medical products.