SKINBUTTONS: FREQUENTLY ASKED QUESTIONS
How much power does Skin Buttons consume?
The setup in our 2014 paper consumes 20mW for a button projector. We acknowledge this is high, but this is highly reasonable for a prototype. Superior integration and future advances in laser technology should continue to push this number down. We can infer from the roughly 5 hour screen-on battery life of the Samsung Gear that its power draw is ~240mW, most of which is likely the display. In comparison, running our 4 skin buttons continuously (no pulsing, etc.) consumes 85mW.
Static icons, although cute and cool, are rather limited. How can you mitigate this limitation?
We plainly acknowledge this limitation in the paper, and describe how it could be overcome in the future using small liquid-crystal displays. Nonetheless, we believe our core idea still illustrates the potential.
Is laser light dangerous to the skin?
The wavelengths we are using have no impact on the skin at the power levels we use.
How is this an improvement over physical buttons?
Our goal is not to beat physical buttons, but to propose an alternative and explore that space. To compare, mechanical buttons must always be large enough for fingers, must consider durability and dust/water resistance issues, and also cannot provide notifications (i.e., no output). Skin buttons could be made very small, perhaps as small as a single IC, yet still provide a comfortable button for user input.
What can this system do that can't be done on a regular screen?
Certainly, anything that could be projected on the skin could also be displayed on the screen. However, this takes up valuable screen space, and requires the main screen be turned on (consuming power). Additionally, interacting with such elements heavily occludes the screen (e.g., scrolling through a playlist to find the song you want to play).