Pixel 4

XDA Developers

Air Gestures

Perhaps the most interesting Pixel 4 leak we’ve seen is the possible use of air gestures, operating the device without having to touch the display. Google’s Project Soli radar chip was first introduced in 2015 at Google I/O, then demonstrated in action working on prototype smartwatch and smart speakers the following year. Indications surfaced in June that this chip might finally be ready for prime time since “skip” and “silence” (mute) media playback gestures are being worked on in Android Q that would require the support of such a chip for the phone to be “aware” of when the user makes such a gesture. While mainline Android Q seems to have a rather limited implementation for exploiting the capabilities of this radar chip, I have no doubt that the development community will come up with some more interesting uses.

I'm really busy, haven't even had a chance to watch this.