At first glance, it’s one of those things that appears relatively benign: Amazon received federal approval the other day to develop a device for tracking your sleep patterns.

Will the device’s radar sensors become an even more intrusive threat to our privacy than the microphones and cameras that the likes of Amazon, Apple and Google already have in millions of homes?

In March, Google revealed the latest version of its Nest Hub smart display. It incorporates what the company calls Soli sensors, which are very similar to what Amazon is apparently now planning to put into Alexa-powered gadgets.

In its request for Federal Communications Commission approval, Amazon acknowledged its radar technology would be “used for sleep tracking and could help improve consumers’ awareness and management of sleep hygiene.” The company described its radar sensors as “capturing motion in a three-dimensional space.” This suggests that rather than logging all the tosses and turns of a restless night’s sleep, as wearables now do, the new device would project an electromagnetic bubble over users.

It would then monitor all movement within that bubble throughout the night “with a higher degree of resolution and location precision than would otherwise be achievable,” according to the FCC application.

Needless to say, unless you turned it off, it would keep tabs on — and share with Amazon — anything that happens within the bubble, sleep-related or otherwise.

“Can sleep-tracking data reveal how many people are in the bed?” wondered Vitaly Shmatikov, a computer science professor at Cornell University.

“Imagine the sleep-tracking data combined with Fitbit data combined with location data from people’s cellphones,” he told me. “The information gathered by each separate device may appear innocuous, but the accumulation and aggregation of data feeds from multiple trackers can reveal intimate details about users’ lives.”

Gaia Bernstein, director of the Institute for Privacy Protection at Seton Hall University School of Law, said radar devices that watch you as you sleep were “particularly concerning” because “federal health privacy laws do not regulate companies like Amazon.”

“Amazon will get access to sensitive health information about us that it can use freely,” she warned.

Sleep data would obviously be highly valuable to a company that runs an online pharmacy and sells pillows and bedding, which, as it happens, Amazon does.

Although being radar-tracked during sleep is one thing, perhaps the more troubling aspect of all this is the introduction of a new technology into the home that allows Big Tech to follow your every movement.

Theoretically, radar-equipped smart devices would be able to “see” all activity in a room and possibly even help identify those present.

“The technology will be used to observe many people through many devices, most of whom don’t have any idea they’re being watched,” said Joshua Fairfield, a law professor at Washington and Lee University who focuses on data privacy.

I posed a simple question about Amazon’s latest advance to the experts I contacted: Clever or creepy? The consensus answer: Both.