Ever since the coronavirus pandemic has started, face masks have become the need of the hour in order to limit transmission of the virus as well as personal protection of oneself to prevent infection.
While many companies have attempted to convert an ordinary face mask into a smart mask that can offer health benefits, engineers at Northwestern University have developed a new smart sensor platform for face masks that they are calling a “Fitbit for the face”.
Dubbed “FaceBit,” this monitoring device for health is a lightweight, quarter-sized sensor, which uses a tiny magnet to attach to any N95, cloth, or surgical face mask. This mask can not only sense the user’s real-time respiration rate, heart rate, and mask wear time.
All health information, including mask fit and wear time is then wirelessly transmitted on the accompanying smartphone app, which contains a dashboard for real-time health monitoring. FaceBit can help wearers better understand their own bodies in order to make beneficial health decisions.
The app also immediately alerts the user when issues — such as elevated heart rate or a leak in the mask — unexpectedly arise. The physiological data also could be used to predict fatigue, physical health status, and emotional state.
“If you wear a mask for 12 hours or longer, sometimes your face can become numb,” said Northwestern’s Josiah Hester, who led the device development.
“You might not even realize that your mask is loose because you cannot feel it or you are too burnt out to notice. We can approximate the fit-testing process by measuring mask resistance. If we see a sudden dip in resistance, that indicates a leak has formed, and we can alert the wearer.”
As stressful events can elicit physiological responses, including rapid breathing, FaceBit can use that information to alert the user to take a break, go for a walk or take some deep breaths to calm down.
Further, FaceBit is powered by a tiny battery, which is designed to harvest energy from any variety of ambient sources — including the force of the user’s breathing, motion, and heat from a user’s breath as well as from the sun. This extends the sensor’s battery life, increasing the time between charges.
“We wanted to design an intelligent face mask for health care professionals that does not need to be inconveniently plugged in during the middle of a shift,” said.
“We augmented the battery’s energy with energy harvesting from various sources, which means that you can wear the mask for a week or two without having to charge or replace the battery.”
In the study, researchers found FaceBit’s battery lasted longer than 11 days between charges. Hester hopes his team or others eventually will be able to make the device completely battery-free in the future by harvesting thermal and kinetic energy, which could solely power the device.
Although Hester’s team has evaluated the device on volunteers in real-world scenarios and found that Facebit’s accuracy was similar to clinical-grade devices. However, he said that the device still needs to undergo clinical trials and validation. The team has released the project as open source and open hardware so others can build and validate the device.
“FaceBit provides a first step toward practical on-face sensing and inference, and provides a sustainable, convenient, comfortable option for general health monitoring for COVID-19 frontline workers and beyond,” Hester said. “I’m really excited to hand this off to the research community to see what they can do with it.”