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Gadget Hears What You’re Eating

Your Fitbit can tell how many calories you’re burning, but no gadget so far can tell you how many you’re taking in

2 min read
1980s man holding a banana to his ear.

Your Fitbit (or whatever it is the activity-enlightened wear these days) can make a pretty good guess at how many calories you’re burning through. And it can do it without any input from you. But if you want to keep track of how many you’re putting in, you’ll still need to do some work yourself, even if it’s only choosing from a menu on an app.

Inspired by that asymmetry, State University of New York at Buffalo computer scientist Wenyao Xu and colleagues at Northeastern University in China developed Autodietary, a necklace-like gadget that attempts to tell what you’re eating.

The device senses sounds from your neck to categorize your meal. It then digitizes and segments the audio data and sends it to a smartphone via a Bluetooth connection. Software on the phone uses machine-learning techniques to analyze differences in sounds as the first three mechanical parts of the digestion process—biting, chewing, swallowing—take place. Each type of food yields a sonic signature distinct enough that so far Xu’s team can tell the difference between apples, carrots, potato chips, cookies, peanuts, walnuts, and water with about 85 percent accuracy. (It was best at identifying water, worst at peanuts.)

imgThe goal of Autodietary is to become a full-service analysis and tracking fool for what you eat and how much of it.Image: University of Buffalo

To get that far required a good deal of work. Xu and his team started by studying how people eat—how many times they chew things, how quickly they chewed—in order to properly program the device. The system also had to be able to filter out the noise of other body sounds, says Xu. Once they got it working, they also had to reduce its power consumption—inserting an eating-sound-activated trigger into the system, so the device won’t waste power while you contemplate your next forkful.

imgMicrophones on the neck pick up biting, chewing, and swallowing sounds. Engineers hope to miniaturize the part of the system that digitizes the sounds and sends them to a smartphone via Bluetooth for analysis.Photo: Univeristy of Buffalo

And there’s more to be done, according to a report that appeared in IEEE Sensors Journal last month. Xu and his colleagues intend to reduce the size of the processing and transmission portion of the device to about the scale of a USB fob. They also hope to use the system to categorize more types of foods and even figure out the volume of food you’re eating.

“Our ambition is to categorize all foods,” says Xu. “But sound may not be enough.” They’ll need to incorporate other types of sensors to tell the difference between very similar foods. After all, Corn Flakes probably sound just like Frosted Flakes, but the latter would make a big difference to your diet.

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Restoring Hearing With Beams of Light

Gene therapy and optoelectronics could radically upgrade hearing for millions of people

13 min read
A computer graphic shows a gray structure that’s curled like a snail’s shell. A big purple line runs through it. Many clusters of smaller red lines are scattered throughout the curled structure.

Human hearing depends on the cochlea, a snail-shaped structure in the inner ear. A new kind of cochlear implant for people with disabling hearing loss would use beams of light to stimulate the cochlear nerve.

Lakshay Khurana and Daniel Keppeler

There’s a popular misconception that cochlear implants restore natural hearing. In fact, these marvels of engineering give people a new kind of “electric hearing” that they must learn how to use.

Natural hearing results from vibrations hitting tiny structures called hair cells within the cochlea in the inner ear. A cochlear implant bypasses the damaged or dysfunctional parts of the ear and uses electrodes to directly stimulate the cochlear nerve, which sends signals to the brain. When my hearing-impaired patients have their cochlear implants turned on for the first time, they often report that voices sound flat and robotic and that background noises blur together and drown out voices. Although users can have many sessions with technicians to “tune” and adjust their implants’ settings to make sounds more pleasant and helpful, there’s a limit to what can be achieved with today’s technology.

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