A new flexible generator has been invented, which allows a wearer to generate power for their electronics simply by moving.
Every portable device has to deal with limited battery life. What if there was a way to power our portable gadgets endlessly while we’re on the move? A new flexible generator can use body movements to generate electricity by use of friction. It converts mechanical energy into static electric energy and stores the charge in our skin. The generator is apparently efficient enough to power small electronics.
If the technology is developed, it may change how we use portable devices. Much akin to a self-winding watch, electronics powered by this technology could remain functional simply by drawing energy from the user as he or she moves and goes about their daily business.
The generator, which was developed at the National University of Singapore and demoed at the IEEE MEMS 2015 conference last week, can deliver a whopping 90 volts of open circuit voltage when touched lightly by a finger. Electrical and computer engineering professor Chengkuo Lee and his collegues from the university demonstrated that the generator can also be used as a sensor to track the users activity.
The pursuit of a device that can harness waste energy from body movements to power electronics and medical devices is not new. In 2012 for example, researchers at Georgia Tech hoped to create a similar device which made use of piezoelectric materials for the same purpose (piezoelectric crystals are used to generate electricity in a wide range of fields, from firearms to electric lighters).
I know we’re all interested in charging our phones, but imagine charging a pacemaker this way.
The technology which powers the new generator however, is based on a phenomenon called the triboelectric effect, in which two dissimilar surfaces generate a charge when brought in close proximity of each other. When the surfaces are then pulled apart or flexed, a potential grows between the surfaces which creates a current. The current can then be harnessed via electrodes.
“Skin, the most abundant surface on a human body, is a natural choice for one of the triboelectric layers,” says Lee’s graduate student Lokesh Dhakar. “[…] Skin as a triboelectric material has a high tendency to donate electrons or get positively charged which is important in improving the performance of the device if the other triboelectric layer intentionally chosen as the one with a tendency to get negatively charged.”
The researchers designed the other surface to be a silicon pad containing thousands of tiny pillar like structures, and a thin 50nm gold strip was used as the electrode. The pillars increase the surface area in contact with the skin, and by extension, increase the power output. When applied to a palm and throat, the device created 7.3 and 7.5 volts when clenching the fist and speaking respectively.
WHen tapping the device, 90volts and 0.8mW of power was produced, enough to light 12 commercial LEDs. The team hopes to make the device more flexible so it can be easily worn on any part of the body without discomfort.
Source: IEEE Spectrum