The term “smart dresser” typically describes someone with a strong sense of style or who is fashion-forward. Researchers from the Federal University of Espírito Santo in Brazil took a more literal interpretation of the term when they developed pants laced with fiber optic sensors that were able to remotely monitor a wearer’s physical activity. The aim of the so-called smart pants is to help health care providers non-intrusively monitor the physical activities — or lack thereof — of aging patients or those in rehabilitation.

Fiber optic sensors are compact and flexible, not to mention that they are immune to both electro- and magnetic interference and have been shown to integrate into different clothing textiles and accessories without much hassle.

The smart pants incorporate transparent optical fibers that are meshed within the actual textile, avoiding the need for image-based monitoring that leads to privacy concerns. The fibers can sense actions that the wearer makes, without hindering ordinary movement, such as walking, running, or performing the Harlem Shuffle. As always, accessories make the outfit. In this case, the smart pants include a portable signal acquisition unit that fits inside a pocket to gather and transmit the data to remote clinicians.

The recent work emerged from a larger project focused on the development of photonic textiles for low-cost wearable sensors. Using intensity variation polymer optical fiber sensors, the researchers were able to obtain more specific readings on a wearer’s movement than they would normally get from a smartphone or a wearable health accessory, such as a smart watch.

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The pants sense motion based on variations in the intensity within polymethyl methacrylate optical fibers measuring 1 mm in diameter. Each fiber has a 10 μ?-thick cladding, with small sections cut away to position sensitive fiber areas in various locations along the leg. The overall mesh culminated in a multiplexed sensor system comprising 30 measurement points per leg to classify specific movements with the help of a newly developed machine learning algorithm.

The testing of the technology resulted in 100% accuracy in classifying activities such as fast and slow walking, squatting, sitting down in a chair, sitting on the floor, front kicking, and back kicking. The next step in the research is to find a way to connect the signal acquisition unit to the cloud to access data remotely and test the smart textile in a home setting — or at the gym or the dance floor. Optical fiber sensors are simple enough to integrate with clothing that being “smartly dressed” could take on a much broader meaning someday soon.

The research was published in Biomedical Optics Express (https://doi.org/10.1364/BOE.492796).