Humans hear sound in relatively narrow dynamic (loudness) and frequency ranges, especially compared to other species. Cats and beluga whales hear sounds with wider loudness ranges and at much higher frequencies than humans. We’ve written about digital hearing aids such as GN Hearing’s 3D devices for people with profound hearing loss. We also covered work at Columbia Engineering with cognitive hearing aids. Human hearing impairments range from variations of mild hearing loss to organic deafness.
Case Western Reserve University researchers are developing ground-breaking atomically-thin hearing “drumheads.” The Case Western work may someday result in a future generation of miniaturized, ultralow-power audio signal sensory devices for human use. In a paper published in Science Advances, the researchers described their work’s focus on highly miniaturized auditory devices and systems with “cat-like” dynamic and frequency ranges. The team developed tunable vibrating nanoscale drumheads made of atomic layers of semiconductor crystals with single-nanometer range thickness and 1-micron diameter. When you consider there are 25,400 microns in one inch and 25.4 million nanometers per inch, the Case Western drumheads are almost unfathomably tiny. According to the study, the drumheads need only nanoWatt to picoWatt (billionths to millionths of watts) power levels to operate. The device size, sensitivity, and power profiles are unprecedented.
The Case Western drumheads’ barely measurable sizes and energy requirements suggest a wide range of potential use cases. Actual implementation likely remains decades in the future, but replacing or augmenting human biologic hearing apparatus could be just the beginning. Broad dispersion of such highly sensitive drumheads across the Internet of Things (IoT) raise for consideration the potential of a world that’s “always listening.”