MindRDR, as the app is called, links up Google Glass with another piece of head-mounted hardware, the Neurosky EEG biosensor, to create a communication loop.

The Neurosky biosensor picks up on brainwaves that correlate to your ability to focus. The app then translates these brainwaves into a meter reading that gets superimposed on the camera view in Google Glass. As you "focus" more with your mind, the meter goes up, and the app takes a photograph of what you are seeing in front of you. Focus some more, and the meter goes up again and the photo gets posted to Twitter. Like this: