Insect Ears Inspire Superefficient Microphones 

Insect ears are inspiring the design of tiny 3D-printed microphones that could pinpoint a sound’s direction, replacing the much bulkier, energy-hungry gear currently needed for such purposes, researchers say.

The insect ear possesses a thin sheet of tissue, known as the tympanum, that is much like the human eardrum. Sound waves make this membrane vibrate, and the sensory apparatus within the ear converts these vibrations into nerve signals.

Although an insect’s tympanum is typically a millimeter or so wide, insects are capable of feats of hearing that currently require devices much larger in size. For instance, to pinpoint which direction a gunshot came from, the vehicle-mounted Boomerang system from Raytheon depends on a microphone array roughly a half-meter wide. In comparison, the nocturnal moth Achroia grisella can also identify which direction sounds are coming from, and can do so with just one tympanum only about half a millimeter wide. (The moth likely evolved this skill for both detecting predatory bats and ultrasonic mating calls.)

In order to mimic what insect ears can accomplish, scientists at first attempted to copy insect structures with silicon microelectromechanical systems (MEMS). However, the resulting devices lacked the flexibility and the microscopic 3D structural variations seen in real insect ears that help them hear so well, says Andrew Reid, an electrical engineer of the University of Strathclyde, in Glasgow.

Now Reid and his colleagues are experimenting with 3D printing to more faithfully copy insect ears. He detailed his team’s research at the annual meeting of the Acoustical Society of America on 10 May in Chicago. The research builds upon the team’s earlier work to understand how insects have such stellar directional hearing.

The researchers have 3D printed a variety of membranes to copy a range of insect tympana. The base material for these membranes is typically a flexible hydrogel such as polyethylene glycol diacrylate. The membranes also often include a piezoelectric material such as the perovskite oxide crystal known as PMN-PT, which can convert acoustic energy to electric signals, and electrically conductive silver-based compounds, Reid says.

Keep reading

Author: HP McLovincraft

Seeker of rabbit holes. Pessimist. Libertine. Contrarian. Your huckleberry. Possibly true tales of sanity-blasting horror also known as abject reality. Prepare yourself. Veteran of a thousand psychic wars. I have seen the fnords. Deplatformed on Tumblr and Twitter.

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: