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You have the power! Soft wearables now powered by human-generated electricity

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Oct 11, 2021, 6:40 PM EDT

No one looks at life as a member of the Borg and thinks it looks like a good time, but the development of technology that can work in concert with our bodies as sensors or therapies, could lead us into a new world of personalized healthcare.

Wearables have become an ordinary part of everyday life and a necessary component of achieving the cyborg future we all dream of (one without authoritarian social structures, hopefully). Smart watches and fitness trackers measure our steps, heart rates, and yell at us when we haven’t stood up in a while. They only work, however, when you’re wearing them. Charging time is lost time, and forgetting them on the charger means a day of lost data. But what if you never had to take them off?

The UCLA Samueli School of Engineering is working toward a new class of bioelectronics which takes energy from the movement of your body to power small devices, eliminating the need to charge them entirely. Their new research was recently published in the journal Nature.

Magnets, of course, have an magnetic field. And when the proximity of two or more magnets is modified, either by pushing them toward one another or pulling them apart, the resistance creates fluctuations in that field which can be harnessed to power devices. This phenomenon, known as the magnetoelastic effect, has been in use in rigid structures, sometimes as a measurement of strain. By placing magnets on or in hard metal structures, for instance, you can measure the strain or torque on those structures by measuring the change in magnetic fields.

These rigid structures, though, don’t work well in wearables because they can’t compress well against the human body, and the changes resulting from flexing a hand or bending a knee don’t deliver the desired push and pull. In order to make it work, magnets would need to be embedded in a soft material capable of forming to the body.

For this study, Jun Chen, assistant professor of bioengineering at UCLA, and their team developed a small generator about an inch wide which could be placed on a person’s elbow. The generator was made of a soft silicon polymer with nanomagnets distributed inside. The individual magnets averaged 10 micrometers (1/100th of a millimeter), smaller than the width of a human hair. This novel material allowed the device to be form-fitting, distributing the magnets over a movable area.

Once applied, the field generated from natural arm motions is sufficient to power the device. In fact, their device generated way more power than was necessary. They measured power output four-times greater than rigid counterparts. In fact, the generator was so sensitive that the movements generated from a user’s pulse are enough to power a heart rate monitor, sweat monitor, or thermometer.

In addition, because the device uses magnetism instead of electricity, humidity or the presence of sweat did not impact its function. During their tests, they sprayed the devices with artificial sweat to measure any impact to performance and found none. They even soaked the devices in artificial sweat for a week and they still performed well.

While still in the development stage, these devices could replace many of the functions currently provided by smart watches, smart jewelry, and other wearables. One can imagine a future of wearable devices which slide over the hand like a glove, are otherwise incorporated into clothing, or exist as standalone devices adhered to the body.

Proof of concept tests also showed the ability to transmit gathered data over the air for storage in the cloud or transmitted to family, friends, or medical professionals. The development of soft, bioelectric health monitors could lead to a future wherein all of your health data is available at a moment’s notice.

Resistance may be futile, but it makes for a good energy source.