Innovative new microphones make voice-enabled devices much more durable
4/4/2017 Revision: The title has been corrected from “New MIT Developed Microphone Can Still Work in Container of Corn Oil” to “University of Michigan Developed a Microphone That Can Still Work in Container of Corn Oil”. It was in fact the University of Michigan that developed this microphone.
Voice-enabled devices like Amazon Echo are becoming ever more popular, but suffer from a lack of battery life, as well as, being a little delicate to take out and about. These new microphones, though, could change all that.
Gadgets we talk to can do very useful and desirable things, from providing music or audio books at our beck and call to making to-do lists and giving traffic updates. But many users don’t consider them hardy enough to take out of the home.
Having music or weather updates right on hand at a BBQ, for example, may be very useful, but there’s also the concern that poor old Alexa might end the day covered in smoke fumes, grease, moisture (coz we didn’t get that rain warning) and even beer.
Now, a startup from Boston – Vesper – has designed microphones that have much greater resistance to all of those threats.
Speaking about the MEMS microphones on their website, Vesper says it “uses piezoelectric materials to create the most reliable and advanced MEMS microphones on the market.
“This is a major leap over the capacitive MEMS microphones that have dominated the market for over a decade.”
Passing the oil test
The MIT Technology Review website displays a video of the technology being put through its paces in a container full of corn oil.
Although most users obviously wouldn’t choose to shake their device around in a tub full of grease, the test is a good demonstration of how the technology could survive if your Echo, for example, spent a long time in a kitchen.
The microphones were also tested in beer, soda, swirling dust, and oil-infused steam.
Around the size of small seeds, the tiny microphones can also stand up to being dropped from a significant height.
As Technology Review points out, regular microphones measure sound with the use of a flexible diaphragm vibrating in proximity to a rigid backplate, and a constant charge is required for the diaphragm, which creates problems.
There is an air gap between that and the backplate, which means the microphone is left susceptible to damage.
Vesper, however, rejects the diaphragm and backplate in favor of single layer of flexible, aluminum nitride cantilevers. An entering soundwave bends the springboard style cantilevers, a process that causes electrical signals to be converted into sound.
In Vesper devices, the presence or absence of that sound energy is a prompt to turn microphones on or off, a great help in conserving battery life.
Vesper CTO Bobby Littrell explained that: “Conventional microphones have to always have their mikes on and use digital signal processing to detect voices.
“That uses a lot more power than our method, which basically tells [a gadget’s voice-interface] system that if there’s no sound it doesn’t need to do any of that computation.”
A sturdier future for Amazon Echo?
Vesper did a test in which it woke up an Amazon Tap speaker and put it back to sleep with the use of minimal power. The startup has also received funding from Amazon’s Alexa Fund.
However, Vesper has not yet confirmed if or when its microphones will be used in Echo or other Amazon devices.
The technology is quite expensive compared to conventional microphones, but Vesper did say their microphones will appear in some consumer devices by the end of this year.
Vesper’s literature certainly sounds like their microphones were not just designed to impress in the lab, with their website saying they wish to “Create the most acoustically rich consumer products for all sound environments.”
“From smartphones and wearables to smart home devices,” they add, “consumers use sound-enabled products in the real world. That’s why MEMS microphones have to work in real-world environments, not just some of the time, but all of the time.”