“The input to this device is a real challenge because there is no physical keyboard—just like a phone doesn’t have a physical keyboard—and there is no touch screen either. How do you input? We’ve dabbled and experimented with lots of different types of input including using your voice, using some type of touch interface on the side of the device itself, as well as using your head,” Lee says. “So using your head as input, for example, we’ve tried dozens and dozens of different types of head gestures. As you can imagine, some are more extreme than others. It creates a pretty funny experience. In fact, we created a game internally, both to exercise and test things out, but also to demonstrate the absurdity of using your head. It’s kind of like DDR but with your head instead of your feet.”

Google’s Project Glass: Inside The Problem Solving And Prototyping