Wink allows Glass users to snap a photo by doing nothing more than winking. Privacy fears aside, it's a pretty sweet feature.
Previously the Wink feature was rumored to officially make its way to Glass, but it never was released by Google. There were developers whothrough sideloading, but again, Google never officially endorsed it.
Fast-forward to the latest OS for Glass, XE12, and the second iteration of the headset and Wink is now included as an official (albeit experimental) feature.
To enable Wink, navigate to the Settings section of Glass and scroll until you find the Wink option. If Wink isn't showing up for you, check the OS version Glass is currently running. You need to have XE12 and and the latest hardware from Google for Wink to work.
Tap on the touch pad and select Calibrate by tapping a second time when prompted.
The setup process requires you to calibrate Glass to help it determine when you are winking, and not just blinking. The first time I calibrated my device, Glass detected my wink right away. But as the feature is experimental, it took only an hour before Wink stopped working and I had to recalibrate Glass. Only, I couldn't recalibrate Glass; it failed to recognize whenever I was winking. I eventually put Glass back on the charger and decided to try later. The next time I tried to set up Wink, Glass recognized and calibrated with little effort.
Once Wink is calibrated and set up, you can snap a photo with a natural wink. This occurs both when the screen is off, and when the screen is on. The first time I tried using Wink with the screen off, I couldn't get it to work. I could only get Glass to take a photo with Wink when the screen was on. Then, shortly after this article was originally published, someone from Google reached out to let me know Wink does indeed work when the screen is off. Upon futher testing, I can confirm it does.
Updated 2:05 p.m. PST: To reflect that Wink does work when the screen on Glass is off.