Crabby-sense tingling? Engineers map crab physiology to suit

Creatures that evolved underwater have wildly different physiology and anatomy to humans and their closer cousins. For instance, the horseshoe crab has a sensory system with a network of multiple ‘eyes’, some of which are photoreceptors that distinguish between light and dark.

With funding from the Office of Naval Research, which has granted him a Young Investigator Award through its Littoral Geosciences and Optics program, Professor Bartlett is putting an electronic version of the horseshoe crab’s unique sensory system to work in a series of soft electronics to be worn by a human.

Bartlett and his colleagues are intrigued by creatures such as the mantis shrimp, octopuses and the horseshoe crab, due to the jaw-dropping variety of natural sensors they all employ. These organisms have the means to adapt their behaviour based on unimaginable information relayed to their brains about their environment; for instance, while human vision is based on three colour-receptive cones (red, green, blue), mantis shrimps have 16 colour-receptive cones.

“These organisms see their world very differently, being able to take in multiple pieces of information to assess their environment,” said Bartlett. “This situational awareness is really remarkable and got us thinking about how we can design sensors to enhance awareness for humans.”

Bartlett’s approach applies the concept of an intricate cognitive system to an integrated electronic network. Inspired by the system through which the horseshoe crab’s movement is informed by its 10 eyes, his team will equip a wearable apparatus with miniaturised sensors to process the environment in motion. Data input from the sensors will be combined to provide a more robust picture of a subject’s surroundings, using a central processor to produce advanced visual, acoustic, and proximity capabilities for navigation.

To develop the technology, Bartlett will source concepts from his background in soft electronics. In a recent project, he developed polymer composites with liquid metal inclusions (devices that replace wires and rigid materials with highly flexible ‘sandwiched’ materials). These devices – which feel like skin, but carry an electrical current – have been adapted for use in soft wireless charging devices and self-healing circuits.

For this crab-inspired sensor array, the engineers will rebuild many of the connected rigid components as soft electronics, accommodating as much free motion and comfort as possible.

“With the development of soft electronics, we see the potential to create wearable devices that feel like a second skin and provide diverse data to the user,” said Bartlett. “This could enhance sensory perception in a way that allows for a better understanding of someone’s environment.”

Bartlett hopes that the second skin-like network could translate to next-generation diving suits made of soft-matter components more like natural tissue (rather than rigid, heavy and restrictive gear), with a greater range of movement, and faster, more natural motor response.

“Ultimately, we aim to significantly advance fundamental knowledge of soft sensing architectures, enabling wearable platforms that mimic underwater organisms and provide real-time sensor data to a user for a better understanding of their environment”, he said.

“What if you could sense the environment all around you? It would be like having eyes in the back of your head.”