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Researchers create thread that senses and tracks movement

Out There | February 8, 2021 | By:

Scanning electron microscopy of threads coated with electrically conducting carbon-based ink.  Bending the coated threads creates strain, which changes their electrical conductivity (normal thread left, bent thread right. Scale bar 200 microns). Photo: Yiwen Jiang, Tufts University. 

Engineers at Tufts University in Massachusetts have created and demonstrated flexible thread-based sensors that can measure movement of the neck, providing data on the direction, angle of rotation and degree of displacement of the head. 

The discovery raises the potential for thin, inconspicuous tatoo-like patches that could, according to the Tufts team, measure athletic performance, monitor worker or driver fatigue, assist with physical therapy, enhance virtual reality games and systems, and improve computer generated imagery in cinematography. 

In their experiments, the researchers placed two threads in an “X” pattern on the back of a subject’s neck. Coated with an electrically conducting carbon-based ink, the sensors detect motion when the threads bend, creating strain that changes the way they conduct electricity. When the subject performed a series of head movements, the wires sent signals to a small Bluetooth module, which then transmitted data wirelessly to a computer or smartphone for analysis. 

The data analysis involved sophisticated machine learning approaches to interpret the signals and translate them to quantify head movements in real time, with 93 percent accuracy.  In this way, the sensors and processor track motion without interference from wires, bulky devices, or limiting conditions such as the use of cameras, or confinement to a room or lab space. 

While algorithms will need to be specialized for each location on the body, the proof of principle demonstrates that thread sensors could be used to measure movement in other limbs, according to the researchers. The skin patches or even form-fitting clothing containing the threads could be used to track movement in settings where the measurements are most relevant. 

“This is a promising demonstration of how we could make sensors that monitor our health, performance, and environment in a non-intrusive way,” said Yiwen Jiang, an undergraduate student at Tufts University School of Engineering and first author of the study. “More work needs to be done to improve the sensors’ scope and precision, which in this case could mean gathering data from a larger array of threads regularly spaced or arranged in a pattern and developing algorithms that improve the quantification of articulated movement.”

The technology, described in Scientific Reports, adds to a growing number of thread-based sensors developed by Tufts engineers that can be woven into textiles, measuring gases and chemicals in the environment or metabolites in sweat.

Source: Tufts University 

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