https://www.theverge.com/circuitbreaker/2017/10/19/16504060/pixel-2-xl-active-edge-sensor-explained-ifixit-teardown

The Pixel 2 comes out today, and so of course iFixit has torn open the first unit it could find to let us see what’s going on inside. The site published its inside look at the Pixel 2 XL this morning, and while there aren’t a ton of surprises to be found (the camera module is pretty large; Google is hiding a secret chip), cracking open the phone does reveal one thing we didn’t know a ton about: how the Pixel’s Active Edge feature actually works.

Active Edge is Google’s name for the feature that lets you squeeze the Pixel 2’s sides to open up the Google Assistant. It turns out, it works using a pair of “strain gauges” on either side of the phone. The setup looks like this: