It seemed capable to telling fingers apart when rubbing against each other, through a sheet of paper or similar.

I suspect they could embed this behind the screen of a smartwatch, and allow broader motions in the air above the watch to select object on the smaller watch face. This in particular as it can detect 3D location, so it can tell a press (moving closer to the screen) from a selection (horizontal and vertical motion).

I wish the title was more useful. For those wondering what Soli is:

Project Soli is developing a new interaction sensor using radar technology. The sensor can track sub-millimeter motions at high speed and accuracy. It fits onto a chip, can be produced at scale and built into small devices and everyday objects.

They say the hardware is ready; so when can we expect developer kits?

I wonder what new possibilities for total spying this approach enables.

If someone were to integrate this into a smartphone/smartwatch as an input device and customize the software, it would be a killer project.

Winner of PopSci "Whats new" award, 1994[0]

[0] https://str.llnl.gov/str/pdfs/01_96.2.pdf