It sounds like something out of science fiction, using existing existing internet electromagnetic signals to power our devices. But given the concerns surrounding ewaste and toxic materials, anything that could make an impact by eliminating batteries is a welcome idea. And if you live in an urban environment, chances are you’re already cloaked in TV and radio waves invisible that are invisible to the naked eye.
And that’s precisely what researchers at the University of Washington have managed to do. Nine months ago, Joshua Smith (an associate professor of electrical engineer) and Shyam Gollakota (an assistant professor of computer science and engineering) started investigating how one might harvest energy from TV signals to communicate, and eventually designed two card-like devices that can swap data without using batteries.
Running on what the researchers coined “ambient backscatter,” the device works by capturing existing energy and reflecting it, like a transistor. Currently, our communications and computing devices require a lot of power, even by battery, in order to function. But as Gollakota explains, all of these objects are already creating energy that could be harnessed:
Every object around you is reflecting signals. Imagine you have a desk that is wooden, and it’s reflecting signals, but if you actually make [the desk] iron, it’s going to reflect a much larger amount of energy. We’re trying to replicate that on an analog device.
The new technique is still in its infancy, but shows great promise. Their device transfers data at a rate of one kilobit per second and can only transmit at distances under 2.5 feet. Still, it has exciting implications, they say, for the “Internet of things.” The immediate use for this technology, everything from smart phones to tablets and MP3 players, is certainly impressive.
But on their website, the team provides some added examples of applications that they can foresee taking advantage of this technology. Basically, they foresee an age when backscatter devices can be implanted in just about anything ranging from car keys and appliances to structural materials and buildings, allowing people to find them if they get lost, or to be alerting people that there’s some kind of irregularity.
As Smith claimed on the team’s website:
I think the Internet of things looks like many objects that kind of have an identity and state–they can talk to each other. Ultimately, I think people want to view this information… That’s part of the vision. There will be information about objects in the physical world that we can access.
The energy harvester they used for the paper, which they presented at the Association for Computing Machinery’s Special Interest Group on Data Communication in Hong Kong, requires 100 microwatts to turn on, but the team says it has a design that can run on as low as 15 microwatts. Meanwhile, the technique is already capable of communicating location, identity, and sensor data, and is sure to increase in range as efficiency improves.
The University of Washington presentation took home “best paper” in Hong Kong, and researchers say they’re excited to start exploring commercial applications. “We’ve had emails from different places–sewer systems, people who have been constrained by the fact that you need to recharge things,” Gollakota says. “Our goal for next six months is to increase the data rate it can achieve.”
Combined with Apple’s development of wireless recharging, this latest piece of technology could be ushering in an age of wireless and remotely powered devices. Everything from smartphones, tablets, implants, and even household appliances could all be running on the radio waves that are already permeating our world. All that ambient radiation we secretly worry is increasing our risks of cancer would finally be put to good use!
And in the meantime, enjoy this video of the UofW’s backscatter device in action: