Korean scientists are developing a powerful new sound and motion sensor that could someday give people, buildings and more the equivalent of “Spidey sense.” This isn't some fantastical plot twist from a new Spider-Man movie, but rather a practical application of the discovery of how spider legs function in the real world.

These “crack sensors” (a.k.a. "nanoscale crack junction-based sensory systems"), which can be worn by people or placed on objects, were inspired by spiders’ crack-shaped slit organs. Residing on spider legs, these organs are made up of the spider’s stiff exoskeleton on the surface and a sort of flexible pad in the gaps, which connects directly to the spider’s nervous system.

Experts see almost endless possible applications of this new technology — for use in everything from sound recording and speech recognition to movement and sensing the earliest tremors before an earthquake. It could also be used as a wearable blood-pressure sensor and for other medical monitoring applications.

These pads are highly sensitive to sound and vibrations, and serve as an early warning system for spiders. It's why a spider almost appears to sense when you're going to swat it with a magazine and escapes before you can complete your swing. In other words, your tiniest movements probably triggered the creepy crawler’s built-in spider sense alert system.

In nature, the cracks on a spider's legs are part of a powerful sensing system. Image: Nature

In a study published Wednesday in the journal Nature, the researchers detail a remarkable example of biomimicry, which uses nature's models as inspiration for solving human problems.

Specifically, the researchers show how to build a mechanical version of these slit-based sensors out of a 20 nanometer layer of platinum on top of a viscoelastic polymer. By deforming the platinum layer to create cracks that open to the soft polymer below, the researchers were able to measure the electrical conductance across the surface of their new sensor.

In tests comparing the sensor’s ability to recognize sound, the crack or mechanical spider sensor outperformed a microphone — at least in challenging audio conditions. When measuring a person saying “go,” “jump,” “shoot” and “stop,” the mechanical spider sensor accurately captured the words in a 92 decibel environment, while a standing microphone could not clearly record the audio.

The scientists achieved a similar result when they attached a sensor to a violin and plucked out a simple tune. It accurately measured the notes, which were converted into digital signals to recreate the tune. They also used the sensor to, when worn on a wrist, accurately measure a heartbeat.

How it’s done

According to experts, there’s good reason why this nano-crack sensor is so good, and it has everything to do with tiles.

“I call it the virtues of tiling,” said Prof. Dr. Peter Fratzl of the Max Planck Institute of Colloids and Interfaces in Germany. Though not involved in this study, Fratzl worked on research that laid the groundwork for the Korean team. In 2009, Dr. Fratzl and Friedrich Barth of the University of Vienna published a paper on the spider’s slit organ.

“We described the biological phenomenon and they took it and turned one of the aspects of it into a technical system,” Dr. Fratzl told Mashable. According to the researchers, it was their study’s lead author, Daeshik Kang, who read Fratzl and Barth’s 2009 paper in Nature and proposed mimicking that geometry for an electro-mechanical sensing system.

The nanoscale crack junction-based sensory systems is based on the same principal as the spider's leg cracks: A stiff surface over a malleable material. The more you stretch or deform the sensor, the wider the gaps and higher sensitivity. Image: Nature

The unusual physiology of the spider’s slit organs is what accounts for their powerful sensing abilities and, apparently, it can be applied to mechanical devices as well. The best way to understand it, explained Fratzl, is to think of the crack sensor as stiff metal tiles glued on top of rubber. If you stretch the length of rubber by 1%, the metal tiles (like the spider’s exoskeleton) do not stretch at all, but the rubber in between each tile (that sensing pad below) stretches by a far greater percentage.

That stretch actually creates a kind of amplification system. Fratzl, who was asked by Nature to write an opinion piece on the Korean team’s research said, “As far as I can judge, they are reaching extremely high sensitivity for tiny, tiny vibrations because of this incredible amplification they built into the system. It’s for measuring minute, minute vibrations.”

"Our mimicked nano crack sensors can give ultra-sensitivity in electrical resistance, since cracks opening and closing can vary resistance significantly,” Professor Mansoo Choi of the department of mechanical and aerospace engineering at Seoul National University who worked on the study, told Mashable in an email.

Because the sensors are already bent or curved, they could work, Mansoo says, as a wearable device. In their studies, they were able to place them on people’s necks for speech recognition and on their wrists to take detailed blood-pressure readings.

He noted that even the smallest variation in these crack gaps can significantly alter electrical resistance, which is something that can be measured. “We show that seemingly harmful (or not useful) cracks could be well utilized to become useful devices. Usually, cracks are known to be a defect to be avoided,” wrote Mansoo.

Korean researchers tried their crack sensor on (from left to right) arms for reading heart rate and blood pressure, necks for voice recognition and violins to record a tune. Image: Nature

"This is a fantastic, exemplary study that shows what can be achieved by a highly imaginative research team and biomimicry," said Professor of Biology at the University of California, Riverside and spider expert Cheryl Hayashi in an email to Mashable. Hayashi was not involved in the new study.

Professor Hayashi agrees, "The artificial versions of the spider sensory organs were shown to be incredibly sensitive to the most subtle of deformations and thus can be used to detect vibrations, even when there is substantial background interference. Hopefully not too long from now, 'spidey-sense' technologies will be a part of our lives."

It will be, though, at least a few years before we're strapping on our first nano-cracked sensors. Mansoo’s team hopes to swap out platinum for cheaper materials and he told us, “A long term stability test should be done … We feel that three-to-five years should be needed to be commercialized.”