INSUBCONTINENT EXCLUSIVE:
The trouble with microphones is that they don''t just hear — they have to listen
Powering the mic and its signal processor means using energy, and energy means a battery, and a battery means charging
This new microphone-like system hears more like the way our own ears do, requiring little or no power, and could help fill the world with
voice-responsive machines
(If that something we really want.)
The device is called a ''triboelectric auditory sensor,& and it works via what called the triboelectric
effect — essentially when two surfaces rub together and create a charge
They&re still trying to figure out why this happens, but what matters to engineers is that it happens reliably.
Triboelectric nanogenerators
have been around for a few years, creating power by having two compatible materials interact with each other at super-small scales
While they&re tiny and highly efficient, they don''t actually produce a lot of power
Researchers from Chongqing University found that, fortunately, you don''t need a lot of power for the purposes of detecting sound.
Our own
ears have what called a cochlea inside them, a sort of long sealed canal filled with liquid and motion-sensitive cells; when sound hits the
end of the cochlea, different parts of it vibrate depending on the frequencies that make up the sound
It basically a Fourier Transform done instantly by organic hardware and is very cool.
The triboelectric auditory sensor does something like
All along its surface are tiny membranes that vibrate when sound waves strike them, causing the materials to rub together and generate a
By recording the different charges from the different membranes with different frequency responses, the device puts together a complete
picture of the sound it hears, using no power but what is created by the nanogenerators
It also extremely sensitive.
Currently it just a prototype, but the researchers demonstrate it in use in various everyday circumstances, so
Such a low-power solution could be a way for, say, a piece of electronics to save energy and sleep all day, only waking when it detects
someone has walked in the room
It a good fit for robots, too, as the device is thin and flat and can even be transparent
No need for ear holes, then.
Hearing aids could also be improved with these: hearing loss often covers a stretch of frequencies — say,
from 500-1,000 Hz — and the triboelectric sensors can be tuned to accept only sound from that span and amplify it for the wearer
No need to accept all the frequencies, process the sound, apply filters, and retransmit it.
These aren''t going to replace microphones
altogether, but they&re an attractive option for applications where energy consumption must be kept to an absolute minimum — and such
applications are multiplying with the growth of IoT and embedded electronics.
