Soli of Google Pixel 4 will allow you to operate it just by waving your hand.

Google has officially announced that Pixel 4 will be coming with innovative Soli technology and Face unlock feature.
Pixel 4 will be the first device with Soli, powering Google’s new Motion Sense features to allow you to skip songs, snooze alarms, and silence phone calls, just by waving your hand without the need to touch it or talk to it.

For the past five years, Google’s Advanced Technology and Projects team (ATAP) has been working on Soli, a motion-sensing radar. Radar is the same technology that has been used for decades to detect planes and other large objects. Google has developed a miniature version located at the top of Pixel 4 that senses small motions around the phone to recognize gestures and detect when you’re nearby.

And, Google Pixel 4 comes with Face unlock feature. As you reach for Pixel 4, Soli proactively turns on the face unlock sensors, recognizing that you may want to unlock your phone. If the face unlock sensors and algorithms recognize you, the phone will open as you pick it up, all in one motion.

News Source: Google Blog