Solar-Powered 'Band Aids' Offer Flexible Energy

Scientists have developed thin, soft stretchy batteries and solar cells that can be applied to the skin like a band-aid.

The flexible power system overcomes barriers experienced by current wearable technologies, according to a report in the Proceedings of the National Academy of Sciences.

Co-author Professor John Rogers, at the Department of Materials Science and Engineering, at the University of Illinois, said these barriers included modest electrical performance and the rigid nature of current systems.

"If you think about conventional electrical devices they are all rigid as a consequence of the fact they are all formed on wafers of silicon," Rogers said.

He said this was a large reason why technology such as smartphones had a stiff construction.

"The question is how do you get from that to something that looks like the skin that matches the shape of the physical body," Rogers said.

The power levels in many current technologies were also often in the "range of microwatts, far short of the milliwatt levels needed to operate realistic forms of electronics, sensors and radios," he added.

Anatomy of Stretchy System The device, developed by Rogers and an international team of researchers from the U.S., China and South Korea is based on miniaturized solar cells and lithium batteries.

"Our batteries and solar cells consist of a tiled array of thin, millimeter-scale components, interconnected together with spring-like wiring," he said.

"When such arrays are embedded, above and below, into a thin layer of a super-soft rubber material and then coated on top and bottom with a slightly stiffer rubber, the systems have soft, stretchy characteristics," he said.

"The active components 'float' in the super soft core layer in a way that mechanically decouples them from the surroundings; the shell layer establishes a robust interface to the skin," Rogers said.

The resulting system could stretch up to 30 per cent without detectable loss in solar power generation, the researchers said.

The researchers tested the device, which is about 2.5 millimeters thick and applied to the skin like a band-aid, in a range of scenarios such as monitoring skin temperature during physical exercise and bathing.

They said the device could be used for a range of practical and medical applications.

"We are envisioning ... full vital signs measurements, via ECG, temperature, blood pressure, respiration rate and blood oxygenation -- all with data streams that match up with clinical gold standards," he said.

He said ongoing monitoring by wearable technologies would also be able to aid patients with muscular or neurological disorders, such as motor neuron or Parkinson's disease.

In the paper the researchers also suggest the ability to monitor temperature could help in the prevention of conditions such as hyperthermia and frostbite in extreme conditions.

Rogers said the technology also had possible applications in monitoring of athletes and possible military applications.

Its versatility was enhanced by the fact the battery could be recharged wirelessly and the laboratory experiments had shown the device maintained its accuracy while completely submerged and was waterproof.

Timeline to Market While the demonstration device described in today's journal only had a lifetime of a few hours, this could be increased, he said.

The way the device was built meant individual components could be adjusted to the specific requirement.

The simple demonstration device could only hold about 10 kilobytes of information, but likewise additional memory could be added, as necessary, he said, adding "that a 'swipe' of the phone extracted the data and cleared the memory."

Rogers said he believed commercial versions of the technology would be available in about two years.

The batteries and solar cells consist of a tiled array of thin, millimeter-scale components.

Odds are you own a wearable computers. This past year has seen explosive growth for such devices, including fitness trackers, phone watches and motion trackers. Shipments for various devices are poised to reach 76.1 million units by the end of 2015, up 163.6 percent from 2014, according to IT research firm IDC. By 2019, worldwide shipments are expected to reach 173.4 million units. It's safe to say the industry is booming. Here’s a look at some of the most popular and intriguing wearables that hit the market this year. These wearables run the gamut in functionality, from tracking heart rate and activity to zapping your brain to improve your mood and sending off an alarm to help prevent sexual assault.

The Apple Watch

The Apple Watch, which debuted in April 2015, is a sleek wearable that resembles a mini iPhone for your wrist. It’s available in different models, including Apple Watch Sport and the Apple Watch Edition. It provides advanced health and activity tracking, including wrist-based heart rate monitoring, and can display updates or control music on your smartphone. Models start at $349.

The health-tracking Fitbit ranges in price from the $60 (for the ZIP) to the $250 (for the Surge). Known as the leader in wearable activity tracking, Fitbit sold 4.7 million devices between July and September this year, according to IDC. Real-time information about activity, exercise, food, sleep and more make this slim device attractive to those trying to improve their overall health.

This wearable zaps your brain to change your mood. The white curved Thync connects wirelessly to a smartphone via Bluetooth low-energy. After pairing it with your mobile device, Thync sends low-level pulses of electricity into your head activating pathways in your brain that make you feel calm or energized.

The second generation Motorola Moto 360 includes a heart-rate monitor, music player and GPS. Starting at $299, this Android watch can also be voice-controlled through the “OK Google” command in Google Search.

With motion-sensing technology and coaching guidance, Moov Now ($79.99), available for both Android and iOS, brings workouts to the next level. The wearable aims to improve almost all forms of exercise with instructions and real-time data, from running to cardio boxing and swimming.

Athena, developed by Philadelphia-based startup Roar for Good, is a coin-size personal safety alarm to help prevent sexual assault. The wearable, which can be worn as a necklace or used an accessory that’s clipped to a shirt pocket, belt or purse, sounds off an alarm and notifies contacts of the user’s location if it’s pressed for three seconds or longer.

A new pair of jeans called #Hellojean, created by Joe’s Jeans, are not only fashionable, but also double as a wearable device, with a dedicated pocked to charge a smartphone (as long as it’s smaller than the iPhone 6). The jeans cost $190 and the battery pack, sold separately, costs $49. The USB cord is hidden in the seams of the jeans so it can “invisibly” connect to the phone.

This wearable motorcycle helmet, with a $1,500 price tag, has a heads-up display, a 180-degree rearview camera and GPS navigation. There’s also a voice-control feature that connects to a phone and can control music.

This insole ($200) tracks your daily steps and calories burned and can also keep your feet warm. Called Digitsole, it provides an extra layer of padding to your sneakers to absorb shock and vibrations when you’re moving.

Like a Glove smart leggings fit all sizes and include sensors that take measurements -- including waist, thighs, hips and inseam -- at the press of a button. The measurements are then sent to an app that helps select the best jean brands that fit your dimensions. The leggings can be pre-ordered for $40.

This decorative activity tracker for women is an accessory that resembles a leaf and can be work on the wrist, collar or neck. In addition to tracking steps and sleep quality, it also tracks menstruation and ovulation and offers guided breathing exercises to reduce stress. The wearable starts at $119.