How Amazon’s radar-based sleep tracking could work

On July 9, Amazon received approval from the Federal Communications Commission to create a radar device that could monitor your sleep health. 

The company states that “it plans to use the radar’s capability of capturing motion in a three-dimensional space to enable contactless sleep tracing functionalities.”

If this sounds familiar, Google deployed a similar sleep-tracking radar system called Soli through its Nest Hub device earlier this year. 

Radar represents an interesting method for tracking sleep: it’s different from how a camera works (which naturally raises privacy concerns if it’s in your bedroom) and it means the sleeper doesn’t have to actually wear anything to track their slumber. Other sleep-monitoring devices include wearables like a Fitbit (also owned by Google), an Apple Watch, or an under-the-mattress sensor, like this one from Withings.

[Related: Skip the wearables and track your sleep with these 5 apps]

“What radar does, when you think about aircraft radar, is it’s tracking the direction and velocity of things,” says Chris Harrison, an associate professor of Human-Computer Interaction at Carnegie Mellon University. “Radar’s been around since WWII, and we’ve been able to miniaturize it and reduce the cost such that you can stick it into a smartphone or a bedside appliance.”

Researchers have been able to use these miniaturized radar sensors to detect multiple individuals, and differentiate between different members of the household and even family pets, Harrison explains. Different research groups have shown that radar sensors can pick up respiration and heart rate, in addition to movement. He imagines that Amazon’s sleep tech will be able to gauge the expansion and contraction of your lungs and the blankets to be able to see how you’re breathing in bed. And if you toss and turn, that has a very distinctive radar signal that can be picked up. 

Harrison welcomes this potential development. “Number one, I think we all need to sleep better,” he says. “Number two, what I really like about this approach is that it’s really innately privacy preserving. No one really wants a camera in their bedroom.” 

That said, a technology like this does have potential concerns that accompany it. “Even though it’s anonymized, and I can’t recognize your radar data over mine, that doesn’t mean it can’t contain very damaging information.”

One way for Amazon to handle privacy concerns would be to not send the data to the cloud. “Do we really want Amazon to know that there were two heartbeats, or one heartbeat, or I had a restless sleep so I wake up in the morning and suddenly all I get on Amazon is sleeping pills they’re advertising to me because they know I had a bad night’s sleep,” he wonders. “I think there’s potential for abuse. As consumers, we should be wary that that’s a possibility and that we want to make sure that we do read the fine print a little more closely and hold companies to an ethical standard.” (Amazon did not respond to requests for comment.) 

Google announced that its sleep-tracking tech would process all data in the Nest device.

Based on Amazon’s communications with the FCC, what we know about the new tech so far is that, similar to Google, Amazon’s “Radar Sensors” will be operated through “touchless control,” which lets users interact with devices without direct contact. Instead, radar pulses that are sent out can sense basic gestures you make in the air and translate them into commands such as replaying a song or turning down the volume. The device will also be “non-mobile,” and can be used only when it’s plugged into a power source. 

Amazon has been eyeing a way to break into sleep health since August 2020, when it announced that its Amazon Halo band would use AI-powered health tools to help users monitor sleep. This new foray comes at a time when Americans should be getting more shut-eye: Approximately 35 percent of adults in the US get less than the recommended seven hours of sleep per night, according to the Centers for Disease Control and Prevention. Losing sleep regularly may negatively impact emotional and physical health. (And of course, you don’t need tech, or monitoring equipment, to get a good night’s sleep.)

[Related: Why do brains need sleep? These ‘twinkling’ star-shaped cells may help us find out]

As for which type of tech is best for analyzing sleep health, Harrison said that each has its advantages. “In general, having the sensor actually worn on your body is always going to provide the best signal. It’s like having the microphone closer to your mouth versus 10 meters away,” says Harrison. 

But, there’s a convenience to a tech that works in the background. “There’s something to be said about something that sits on your bedside table that you plug into the wall and it’s there every night, and you don’t really have to think about it,” he adds. “The technologies that are invisible, that even the laziest of us can adopt into our routines, I think are ultimately the most successful.”