E-Whiskers Are the Latest Robot Accessory

As if it weren’t already obvious that crossing robots and cats would result in something awesome, a team of engineers and computer scientists have developed mammalian inspired whiskers that could give bots and other devices new sensing capabilities.

A team from the University of California, Berkeley, led by Ali Javey, made whisker-like sensors out of carbon nanotubes and silver nanoparticles that are highly sensitive, just like those of a cat (or a rat, or an insect, or any other naturally whiskered creature).

In a paper published in the journal PNAS, the researchers explained that their work built on previous attempts to mimic biological systems in electronics. Javey has previously been involved in developing “e-skin” and there have also been attempts to build “e-eyes.” “Whiskers present yet another important class of sensor components that can monitor the air-flow, mediate tactile sensing for spatial mapping of nearby objects, and even enable balance during motion for advanced robotics with capabilities resembling those found in certain insects and mammals,” the study authors wrote.

People have tried to make e-whiskers before, but it’s difficult to develop a sensor that’s lightweight enough, yet also highly sensitive, and robust—as usual, nature’s pretty difficult to match. But in this study, the researchers found a composite of materials that struck a good balance. Their whiskers are made of elastic fibres,  coated in carbon nanotubes and silver nanoparticles, which together make them bendy, conductive, and strong.

The resulting whisker-sensor is so sensitive it can pick up the pressure of a single pascal, which the lab characterises as “about the pressure exerted on a table surface by a dollar bill.”

As a proof of concept, Javey's team tested their whiskers’ ability to map air flow. Alas, they didn’t go quite so far as sticking them on a robo-kitty, but rather positioned seven whiskers on an upturned dome. They then directed nitrogen gas around the dome to mimic wind, and the whiskers responded accordingly.

The electronic resistance of the whiskers changed according to the velocity of the wind they felt (so if they were right in the path of the wind, you’d expect them to change more than if they were just nearby), which allowed the researchers to map the wind. “The results demonstrate the ability to map airflow in real time with high sensitivity, and provide just one example system which these e-whiskers could be used for monitoring the environment,” they wrote.

As well as measuring wind, the whiskers could sense objects in their environment, like some animals with whiskers do. What’s particularly remarkable, in fact, is that the sensitivity of the e-whiskers can be adjusted for different applications by tweaking their composition—the more silver nanoparticles, the more sensitive they are. The researchers singled out human-machine interfaces, advanced robotics, and biological applications as potential areas of interest. Popular Mechanics reported the sensors could be used in wearable tech, for instance, where they could sense things like movement or heart rate.

Fans of animal-inspired robots might suggest they could also stick some on the Cheetah-Cub robot for the ultimate biomimetic bot.