This special panel of glass is a Liquid Crystal Light Valve (a.k.a a LCD Controllable Blackout Panel) and they’re mainly used in welding helmets because it can protecting your eyes from really bright sparks.
Sandwiched in between two sheets of glass is a layer of liquid crystal material. When voltage is applied to the electrodes, it turns dark and filters out bright light. Depending on how much voltage is applied, you can control the tint or opaqueness of the glass. Check out the guide from the Ruiz Brothers to learn more and try making your own with these items in the Adafruit shop!
Every Wednesday is Wearable Wednesday here at Adafruit! We’re bringing you the blinkiest, most fashionable, innovative, and useful wearables from around the web and in our own original projects featuring our wearable Arduino-compatible platform, FLORA. Be sure to post up your wearables projects in the forums or send us a link and you might be featured here on Wearable Wednesday!