Flexible body-worn sensors that conform to the skin have great potential for monitoring patient health, conducting long-term studies, and giving consumers a way to track their exercise and overall health. Although there have been flexible sticker-like body monitors developed in the past, they have all involved rigid electronic chips and batteries. So, although they’re flexible and can be worn on the skin, they’re still rather bulky and require recharging.
Now, a team at Stanford University have developed highly flexible sticker sensors that don’t have any on-board electronic chips or any other rigid components. They’re powered by nearby radiofrequency devices that can be integrated into clothing. The stickers obtain enough electricity to activate their sensing mechanism, and also to transmit the readings back to the devices built into the clothing.
The stickers rely on a modification of radiofrequency identification technology, which takes advantage of flexible antennae, and compensates for movement, to generate high data transmission rates at low voltages.
Called BodyNet, the technology has already been successfully tested in detecting the pulse and respiration rate when the stickers are applied to the wrist and abdomen. Placing the same stickers over the elbows and knees provides data on the movement of those joints.
Other sensing capabilities are already in the works, including detecting temperature, sweat and other bodily secretions, which can help with monitoring athletic performance and stress.
It is hoped that this technology may replace the current paradigm of wearable devices that can only be placed over very few parts of the body and that provide limited actionable data. “We think one day it will be possible to create a full-body skin-sensor array to collect physiological data without interfering with a person’s normal behavior,” said Zhenan Bao, one of the research leads.
Currently, the sensor stickers and receivers through which they transmit their readings have to be kept quite close, requiring one for every sticker. The Stanford researchers are planning on overcoming this with antennae woven into clothing that can better communicate with the sensors.
Study published in Nature Electronics: A wireless body area sensor network based on stretchable passive tags
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