Smartphone Battery Problems May Be Solved With Power-Generating Shoes

The smartphone is a staple of modern life. While retaining its original moniker “phone” and the ability to make telephone calls, in the last five years these devices have evolved far beyond simply of being a portable telephone. They are powerful and complex portable computers which connect hundreds of millions of people to the internet. But they’re plagued by a deep and core problem: their batteries are notoriously short-lived, many requiring a daily recharge.


Enter Professor Tom Krupenkin of the University of Wisconsin-Madison, and his team. They’ve been working on an innovative and possibly groundbreaking idea – that of generating power for a smartphone from the motion of walking, via advanced technology embedded in footwear.


The idea of motion-generated power isn’t entirely new – watches which charge themselves from the natural motion of your arm during the day already exist, for example – but the idea of generating smartphone power from walking is novel.


"Human walking carries a lot of energy," says Professor Krupenkin. "Theoretical estimates show that it can produce up to 10 watts per shoe, and that energy is just wasted as heat. A total of 20 watts from walking is not a small thing, especially compared to the power requirements of the majority of modern mobile devices." As most smartphones require about two watts of power, the potential from walking far exceeds the amount needed by them.


The research team have used a process whereby tiny bubbles at high speed which grow and “pop”, this creates a high-frequency electric charge, enabling efficient energy conversion.


"The bubbler really shines at producing high power densities," said Professor Krupenkin. "For this type of mechanical energy harvesting, the bubbler has a promise to achieve by far the highest power density ever demonstrated."


Shoes equipped with this “bubbler” technology could provide power to a smartphone via a cable, but another, more interesting way of it extending the phone’s battery life has been proposed: the shoes could become a wi-fi “middleman”, connecting to the internet via 3G or 4G using the power generated by walking and generating its own wi-fi field, to which the smartphone could then connect. Because the smartphone would be connecting to a nearby wi-fi field rather than a distant mobile network tower, the drain on its batteries would be greatly decreased. This ingenious method of power-generating shoes indirectly relieving the drain on a smartphone’s batter rather than directly supplying it with power has one major drawback, however: if the shoes connected to the internet they would have an IP address and internal software and therefore be in danger of being hacked! Perhaps a future exists where strong passwords and encryption for your shoes is something you’ll need to worry about!