Soli sensor
A millimetre-wave radar that can detect micro motion of a human hand.
Project Soli emerged from the work of Google Advanced Technology and Projects group. Using a sensor that operates between 57 and 64 GHz, Soli devices capture motion in a three-dimensional space using a radar beam. Data collected by the Soli sensor can then be used to enable touchless control of device functions or features. For instance, sensor data allow devices to be more "aware" of their surroundings to permit them to enter sleep mode due to inactivity, or to allow users to trigger simple actions without having to touch the device. With higher signal powers, the radar signal could also penetrate fabrics, enabling controls that could work in a pocket or a backpack, and there would be more flexibility to integrate the Project Soli sensors in devices that partially occlude the antennas due to mechanical constraints, according to Google.