Wearable Microfluidic Diaphragm Pressure Sensor for Health and Tactile Touch Monitoring

Yuji Gao, Hiroki Ota, Ethan W. Schaler, Kevin Chen, Allan Zhao, Wei Gao, Hossain M. Fahad, Yonggang Leng, Anzong Zheng, Furui Xiong, Chuchu Zhang, Li Chia Tai, Peida Zhao, Ronald S. Fearing, Ali Javey*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

374 Scopus citations


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.

Original languageEnglish
Article number1701985
JournalAdvanced Materials
Issue number39
StatePublished - 18 Oct 2017


  • diaphragm pressure sensors
  • flexible pressure sensors
  • liquid metal
  • microfluidics
  • wearable


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