Hair That Can See Everything: Sensors of the Future

Every species has evolved over thousands of years to adapt to the environment they inhabit. For example, bats use echolocation, relying on sound waves instead of sight, and certain bacteria live in the sea and use chemosynthesis, converting chemicals instead of sunlight into chemical energy. Evolution exists to allow organisms to survive, but humans have circumvented evolution through technology. As a species we inhabit locations in which we would not have survived had we not developed agriculture, trade and travel. By discovering, exploring and creating, we have built technology based on the laws of the universe that has enabled us to progress.

As our technology has improved, we’ve looked to nature to give us direction. Researchers at the University of Dallas (UD) are studying seals and the way they experience the universe. Seals use whiskers, touch receptors that allow animals to make better sense of their environment, to feel the flow of water. Seal whiskers help these animals to pinpoint the location of fish in the water based on turbulence, allowing them to hunt more efficiently. Jonathon Reeder, a post-doctoral researcher of UD is creating electronic whiskers (e-whiskers) using polymers, with the hope that they can work as whiskers do in nature.

Image of e-whiskers as air is blown from beneath them.

Using knowledge of both mechanical engineering and materials sciences, the team created the e-whiskers by cutting them out of a flat sheet of shape-memory polymer, as seen above. This material is naturally rigid but gains flexibility when heated. During this process, a flexible strain sensor is placed atop each sensor, with the diameter of a human hair, and remains attached to the sheet. The strain sensor converts the deformation due to force, pressure or weight of a singular e-whisker into a measurable change in electrical resistance. As hot air is blown through the bottom of the sheet, the whiskers rise and become 3D, allowing the strain sensors’ changes in resistance to track the position of each e-whisker. The high density of the e-whiskers makes it possible to measure force, pressure, proximity, temperature, stiffness and topography.

The applications of e-whiskers are almost inconceivable. By duplicating the sensing capabilities of humans, we have the ability to integrate this development into previously developed technology. The two largest applications for the e-whiskers are projected to be robotics and prosthetics.

Robots could benefit from the technology by collecting a larger array of information about their environment before taking action, as they require environmental data in order to perform accurately. By replicating the sensing capabilities of humans, robots can identify qualitative attributes of the environment they are working in, such as hardness, roughness and temperature. This allows them to respond to their environment appropriately. Tasks that previously were too delicate for robots, or have highly variable environments, will soon have the potential to benefit from robotic assistance.

Electrodes from a brain-computer interface implanted in a man’s brain that was linked to a robotic hand with tactile sensors, demonstrating current technology.

Alternatively, while integrating sensors into prosthetics actively improves people’s lives, it’s a more long-term goal. Biology is complex, and while our nervous system transmits information using electrochemical signals, they are quite different from the electronic signals in sensors. Currently, research is being conducted to set up an interface that will allow electronic and neural tissues to meet. However, having them communicate and interact is still a work in progress. Right now, any combination of electronics and neural networks involve fairly invasive operations. The building blocks are being set up for the game-changing point when accurate communication occurs between the brain and electronics.

Eastgate Centre, designed for low energy impact using biomimicry.

Biomimicry, defined as the design and production of materials, structure and systems that are modeled on biological entities and processes, is becoming more common. An amazing example is an energy efficient building in Zimbabwe, Eastgate Centre, which is modeled after termite mounds. Termites live in areas with huge temperature variations and yet they keep their homes at the specific temperature needed to grow the fungus they feed on. Termites achieve this by opening a set of heating and cooling vents over the course of the day to encourage convection currents. The Eastgate Centre doesn’t use conventional air conditioning or heating and yet is the country’s largest office and shopping complex. You can read more about it here.

Another example of biomimicry is the Gecko Gripper, a NASA invention. Geckos have special hairs on their feet that allow them to stick to vertical surfaces through Van der Waals forces. The Gecko Gripper uses “gecko adhesive” that uses microscopic angled hairs that can turn their adhesion on and off based on a sliding motion of the hair patterns. The grippers can be used for mounting small devices and for robotic inspection due to the fact that they never wear out. For more information about the Gecko Gripper, click here.

Everyone likely has their own opinion about hair, but when it comes to technology, the more hair the better. Robots are already mired in human tasks such as building furniture, which you can read about here; however, by enhancing robots with human-like attributes, such as the sense of complex touch, they have the potential to do even more. As we continue to follow biology with technology, we are sure to continue discovering.