Harvesting energy from the human body and environment
Opportunity
Wearable electronics or wearables are devices that provide some form of intelligent assistance. First applied for health monitoring in hospitals, wearables now range from activity trackers to smart eyewear. With their ease of use and portability, wearables have grown in popularity. According to Grand View Research, the US$33 billion global wearables market will likely have a compound annual growth rate of around 16 percent until 2027.
As convenient as these wearables are, their battery life remains the biggest pain point until now. The Apple Watch lasts 18 hours on a single charge, while Fitbit’s trackers can last around a week. Because batteries in wearables must also be small and lightweight, battery life extensions typically rely on advancements in processors or software. Although photovoltaics can be used to harvest energy, they require solar panels and the wearer’s constant exposure to the sun.
The human body has also been proposed as an alternative power source. Energy may be harvested through the wearer’s movement as well as by exploiting energy or temperature differences between the body and environment. Energy may also be wirelessly delivered through the body by batteries, though the battery’s placement along the body affects effective energy transfer. With the human body’s potential for powering wearables, technologies are now being developed to make the process a reality.
Technology
This invention describes a method for passively harvesting and actively delivering electromagnetic energy in the air for the potential use of powering wearables. Through the invention, wearables worn on the body can be charged by ambient energy or even by a single battery source transmitting energy through the body.
The first approach exploits the low-frequency electromagnetic waves found in the environment, such as the 50-60 Hz typically radiated by our electricity networks. These electric fields can be transferred through the human body and into the wearables. An electrode then converts the alternating current into direct current, enabling the stable charging and power storage of the wearables.
Unlike other methods for powering wearable devices, the invention’s function is unaffected by its size or location on the body. Moreover, its ability to deliver stable power in a wireless state paves the way for more convenient and long-lasting wearables. Because of these characteristics, the invention could be used in wireless body area networks (BANs).
In these networks, wireless sensors connected to the body constantly measure various parameters and transmit the data to monitors. Given the novelty and advantages posed by the invention, it could potentially solve the battery life conundrum of wearables and accelerate their widespread adoption.
Body-coupled energy harvesting and transferring method and apparatus
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