Researchers from the University of California, Berkeley have devised a new, high-tech way for people to experience what it’s like to have echolocation, the ability to use sound to communicate and detect objects around them, similar to bats and dolphins.
In a study published in the Proceedings of the National Academy of Sciences, physicists at the university explained how they used graphene to construct a lightweight ultrasonic receiver and transmitter capable of measuring the speed and the distance of nearby objects.
“Sea mammals and bats use high-frequency sound for echolocation and communication, but humans just haven’t fully exploited that before, in my opinion, because the technology has not been there,” said Alex Zettl, a senior scientist at Lawrence Berkeley National Laboratory and a member of the Kavli Energy NanoSciences Institute.
“Until now, we have not had good wideband ultrasound transmitters or receivers. These new devices are a technology opportunity,” he added.
Ultrasound unit can be used underwater to penetrate steel
The wireless ultrasound devices aren’t just a novelty – they have practical uses as well, as the study authors noted. They can be used along with standard radio transmission in regions where radio is impractical, such as underwater. The new devices can use electromagnetic waves, similar to current ultrasound or sonar devices, but with far more fidelity, they said.
In addition, they can be used to communicate through steel or other objects that electromagnetic waves normally are unable to penetrate. The devices use diaphragms made out of one-atom-thick graphene sheets that are able to respond to frequencies ranging from subsonic to ultrasonic (or from well below 20 hertz to more than 500 kilohertz).
WTF is graphene, though?
Graphene is a material made from carbon atoms arraigned in a hexagon (similar to chicken wire) that creates a tough-but-lightweight sheet that has unique electronic properties. It’s lightweight enough to respond well to different frequencies of an electronic pulse and is also more efficient, converting more than 99 percent of the energy that drives the device into sound. In comparison, current conventional speakers covert just eight percent.
“Graphene is a magical material; it hits all the sweet spots for a communications device,” Zettl said. “There’s a lot of talk about using graphene in electronics and small nanoscale devices, but they’re all a ways away. The microphone and loudspeaker are some of the closest devices to commercial viability, because we’ve worked out how to make the graphene and mount it.”
“Because our membrane is so light, it has an extremely wide frequency response and is able to generate sharp pulses and measure distance much more accurately than traditional methods,” added Zhou. “This is lightweight enough to mount on a bat and record what the bat can hear.”