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Wearable Microfluidic Diaphragm Pressure Sensor for Health and Tactile Touch Monitoring
Author(s) -
Gao Yuji,
Ota Hiroki,
Schaler Ethan W.,
Chen Kevin,
Zhao Allan,
Gao Wei,
Fahad Hossain M.,
Leng Yonggang,
Zheng Anzong,
Xiong Furui,
Zhang Chuchu,
Tai LiChia,
Zhao Peida,
Fearing Ronald S.,
Javey Ali
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201701985
Subject(s) - wheatstone bridge , materials science , polydimethylsiloxane , pressure sensor , microfluidics , tactile sensor , wearable computer , diaphragm (acoustics) , biomedical engineering , nanotechnology , acoustics , voltage , computer science , electrical engineering , resistor , mechanical engineering , robot , embedded system , vibration , artificial intelligence , engineering , physics
Flexible pressure sensors have many potential applications in wearable electronics, robotics, health monitoring, and more. In particular, liquid‐metal‐based sensors are especially promising as they can undergo strains of over 200% without failure. However, current liquid‐metal‐based strain sensors are incapable of resolving small pressure changes in the few kPa range, making them unsuitable for applications such as heart‐rate monitoring, which require a much lower pressure detection resolution. In this paper, a microfluidic tactile diaphragm pressure sensor based on embedded Galinstan microchannels (70 µm width × 70 µm height) capable of resolving sub‐50 Pa changes in pressure with sub‐100 Pa detection limits and a response time of 90 ms is demonstrated. An embedded equivalent Wheatstone bridge circuit makes the most of tangential and radial strain fields, leading to high sensitivities of a 0.0835 kPa −1 change in output voltage. The Wheatstone bridge also provides temperature self‐compensation, allowing for operation in the range of 20–50 °C. As examples of potential applications, a polydimethylsiloxane (PDMS) wristband with an embedded microfluidic diaphragm pressure sensor capable of real‐time pulse monitoring and a PDMS glove with multiple embedded sensors to provide comprehensive tactile feedback of a human hand when touching or holding objects are demonstrated.