Smart Pants Track Physical Activity

Engineers at the Federal University of Espirito Santo in Brazil have developed smart pants that can non-intrusively track physical movements and provide updates to caregivers if the people they’re taking care of are showing signs of distress. This application could be very useful for people who are monitoring elderly patients in healthcare facilities. The technology may also be applicable in tracking and quantifying movements, such as range of motion, for patients undergoing physical rehabilitation. The pants contain a series of fiber optic cables and a signal acquisition unit that can be carried in the pants pocket. When the optic cables are bent by the wearer’s movement, the optical signal is altered, providing a measurable signal. The system also includes machine learning algorithms that interpret the optical signals as different movements and classify gait.

Elderly people can experience falls and other health emergencies, requiring monitoring by caregivers. However, this can be difficult to achieve as it is impossible to supervise such people all day, and installing cameras in bedrooms, for instance, could create serious privacy issues. Developing a non-obtrusive way to monitor someone’s movements would be very useful in such circumstances. This latest technology aims to achieve this through a pair of smart pants that can track and identify movements non-intrusively.

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“Our polymer optical fiber smart pants can be used to detect activities such as sitting, squatting, walking or kicking without inhibiting natural movements,” said Arnaldo Leal-Junior, a researcher involved in the study. “This approach avoids the privacy issues that come with image-based systems and could be useful for monitoring aging patients at home or measuring parameters such as range of motion in rehabilitation clinics.”

The researchers describe the technology as a “photonic textile” and it contains a network of transparent optical fibers made from polymethyl methacrylate that are just 1 millimeter in diameter. The pants contain 30 measurement points in each leg, allowing the system to characterize a wide range of movements.

“Fiber optic sensors have several advantages, including the fact that they are immune to electric or magnetic interference and can be easily integrated into different clothing accessories due to their compactness and flexibility,” said Leal-Junior. “Basing the device on a multiplexed optical power variation sensor also makes the sensing approach low-cost and highly reliable.”

So far, the researchers have tested the technology on human volunteers who put it through its paces by performing a variety of physical movements including walking, squatting, sitting on a chair, and kicking. The system could identify these movements with ease.

“This research shows that it is possible to develop low-cost wearable sensing systems using optical devices,” said Leal-Junior. “We also demonstrate that new machine learning algorithms can be used to extend the sensing capabilities of smart textiles and possibly enable the measurement of new parameters.”

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