Google has been granted a patent for a projection system to display buttons and controls from a headset, according to a patent filing granted to Google on Thursday (uncovered by Engadget). In the patent art, the projector is shown as mounted inside a set of glasses, not entirely unlike the Google Glass project set to reach more developer hands this year.

The art shows a person wearing the glasses with two control schemes projected on their person: in one diagram, a number pad on their palm, and in another, a set of four buttons on the inside of their wrist. Another diagram shows the number pad mirrored inside the glasses display, as if the glasses would be able to show in a HUD which buttons were being pressed so the wearer would not have to focus directly on the number pad projected on their arm.

Inside the text of the patent, Google suggests further uses for the projector: “the processor may detect when the display hand is moving and interpret display hand movements as inputs to the virtual device.” Hence, the projector would not only display interactive control schemes but would also be able to accept gesture inputs to control what’s happening inside the glasses display.

The patent also covers many finer points of the design, such as how the glasses would determine the appropriate time to display controls (a gyroscope would detect when the head is moving) and when to stop projecting them (a camera could see, for instance, when the palm projected with the number pad falls to the person’s side). We’ve been wondering how Google might deal more subtly with control schemes than requiring users to speak commands or just use their smartphone, as with competing smart glasses. This projector could do the trick.