Bangalore: Walking is good for health, but if walking can also generate electricity, well enough to power small gadgets, it can impact millions of people across the world.
At least that’s the idea behind a new, knee-mounted device that harvests energy from the end of a walker’s step, almost in the same way that hybrid electric cars recycle power from braking.
Researchers from the universities of Simon Fraser in Canada, and Michigan and Pittsburgh in the US, report in Friday’s issue of Science that they have developed a biomechanical energy harvester which, unlike similar conventional devices requiring users’ focused attention at the expense of other activities, can generate electricity with minimal user effort.
The devices comprise a knee brace that’s rigged with a simple motor and a single-gear clutch system. With a device on each leg, volunteers generated about 5W of electricity, while using little additional energy. That’s enough power to run 10 cellphones at the same time, and twice the power needed for computers in developing regions. By running, one volunteer even generated 54W, but researchers say the cost of this extra effort remains unknown.
“Such devices, when focused on individuals, are very effective. It’s the convenience of being independent, not being hooked to any power supply, which is important,” said Pushpito K. Ghosh, director of the Central Salt and Marine Chemicals Research Institute in Bhavnagar, Gujarat. Ghosh’s team has developed a desalination unit that runs on “animal power” (cattle, camel or others)—mechanical energy from animals is converted into electricity—to make brackish water potable. The group is improving its unit design to desalinate seawater.
Converting biomechanical energy to electricity is an old concept, says Ghosh, but unless “applications are targeted to areas where nothing else exists, the technology doesn’t quite take off.”
Knee-brace researchers are aware of this. Led by J. Max Donelan of Simon Fraser University, they have their eyes set on at least two markets that have compelling needs: military units, which use a lot of modern technology today and carry up to 13kg of battery weight per soldier, and the medical devices market.
They have set up a company called Bionic Power Inc. in Vancouver, Canada, to begin the commercialization. The plan is to have a prototype ready for the military in 18 months.
“That’s the way to go—develop a technology, publish, and then commercialize it,” said Ghosh, who after setting up a few desalination units in different parts of the country, couldn’t commercialize it even after generating interests in places as far as Kenya, and at the United Nations. “We never marketed ourselves.”
But, Donelan and his colleagues are focused on commercialization. “Our findings are important because portable electricity represents much more than just a convenience to some people,” said Donelan. He believes it allows a soldier to communicate, navigate and get home safely.
On the medical front, researchers believe the device might help drive robotic arms for people with missing limbs or hands. It might also extend the battery life of implanted insulin pumps.
As the company website goes live after the Science publication on Friday, Bionic Power chief executive Yad Garcha is optimistic that it should generate interest in large companies. “Big cellphone and laptop companies should find our technology useful,” said Garcha in a telephone interview.
For military applications, the company wants to work with large defence contractors such as Raytheon Co. and General Dynamics Corp. in the US and Thales in Europe.
In the developing world, researchers think, among other uses, the device can ensure cleanliness of drinking water and powering of computers in remote regions.
Garcha, who was born in Moga, Punjab, but left India more than 30 years ago, says even though the need in the developing world is as compelling as the military, applications are a little way off. Unless some large consumer company comes forward to licence and commercialize the technology, to which Bionic Power is open, the start-up would rather focus on making a “smaller number of high quality products”.
But V. Ramgopal Rao, professor of electrical engineering at the Indian Institute of Technology, Bombay, thinks that the applications for military and prosthetics are feasible, the device would perhaps never be useful for the developing world.
“I doubt if anyone is ever going to use these sort of technologies in the third world since there are better options available for generating electricity—solar, wind or fuel cells, which will be eventually cheaper and more practical,” said Rao.
He is developing an integrated system to provide point-of-care diagnostic support for cardiovascular diseases. The system under development monitors the molecular markers to detect cardiac attacks, particularly incipient attacks that go undetected before major attacks occur.