Everyone is online these days. Pretty soon, “everyone” could include inanimate objects like your couch and your car keys.
“Ambient backscatter” might sound like an experimental music genre, but it’s actually a groundbreaking method of networking developed by researchers at the University of Washington. Bringing us one step closer to an Internet of Things reality, the technology allows devices to communicate with one another wirelessly and with no batteries. Instead of creating their own signals, ambient backscatter devices essentially freeload off existing signals from radio, TV, cellular, and Wi-Fi networks, which invisibly blanket much of the earth. It’s a bit like stealing your neighbor’s unlocked Wi-Fi, except on a much grander scale.
Vamsi Talla, one of the University of Washington developers, spoke to Co.Design about the advantages of ambient backscatter. “We started out by looking at the problems faced by today’s sensing and computation devices. As an example, use of Wi-Fi on phones or GPS on wearable devices, such as Google Glass, consumes large amounts of power and drains the battery,” he says. And traditional radio communication requires the expensive generation of radio signals. Talla's team wanted to explore more power-efficient means of communication, and realized that they could just leverage the wireless signals already surrounding us instead of making more.
"Imagine that you misplace your keys," Talla offers. "The keys can use ambient backscatter to communicate with nearby objects, such as the couch, localize themselves with respect to surrounding objects, and then send the user a text alert.”
A video the researchers developed includes an image of a phone receiving a text message from “The Couch.” “You left your keys,” says the sweet sofa. The video does not include the “Thx luv u Couch xo!” reply from the user.
These battery-free devices can also be embedded in walls for long-term home monitoring. Another important application of ambient backscatter is wearable computing. As the technology requires far less power than, say, Bluetooth or Wi-Fi, it can therefore drastically improve the battery life of wearable devices, and even eliminate the need for batteries altogether. The small sensors would suit the Nike+ system, Jawbone Up, or Fitbit.
“The main challenges here revolve around the fact that we are trying to use uncontrollable, pre-existing signals, which already contain data,” said Talla of the team’s design hurdles. “However, using our unique communication circuits and protocols, we developed this ultra-low-power technology.” The team says ambient backscatter technology should reach the market in the next few years.