The whiskers that help rats find their way around dingy sewers has inspired a tactile sensor that could be used for navigating all manner of dark conditions. Scientists have developed a device capable of generating images of obscured environments by monitoring both air and fluid flow, and which could find its way into biomedical applications.

Researchers working at the University of Illinois at Urbana-Champaign and its affiliate, the Advanced Digital Sciences Center in Singapore, built the sensor using super-elastic Nitinol wires and coating them in plastic straws. The whiskers each measure around 15 cm (6 in) long and 3 mm (0.12 in) thick. By attaching strain gauges at their base and applying air flow with a regular hair dryer, the system is able to track the movement of each individual whisker.

"We measured the amount of bending due to the impinging air-flow with the whisker array from multiple directions to produce tomographic images of the air-flow similar to a CT scan," lead researcher Cagdas Tuna explains to Gizmag. "We also repeated these experiments in an open water channel using a water pump to extract 2-D cross-sectional images of the generated water-flow."

There's no evidence to suggest that whiskered animals like rats and seals create such imagery in their brains, but their bristles do help them navigate obstacles and spaces all the same. The researchers say that the whisker-inspired system can complement existing methods of navigating, tracking or detection in the dark. These typically involve radar or sonar technologies to map the environments, but are yet to really incorporate tactile signals.

We have seen research efforts in the past turn to the animal kingdom to help find our way around in the dark. Early last year, scientists at Berkeley Lab created tactile sensors based on cat's whiskers that respond to pressure as slight as that of a dollar bill resting on a table (around 1 Pa).

The University of Illinois researchers will now focus on improving the imaging model and making the system smaller to improve its versatility.

"This may even find use in biomedical applications, such as cardiac surgery," says Tuna. "A thin-whiskered catheter tip could be used during surgery to track the relative position inside the heart, potentially reducing the risk of injury, or atrial fibrillation."

The research was published in the journal Bioinspiration and Biomimetics.

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