Someone has an iWatch, so the watchband on the outer wrist side could beam a little group of buttons onto the wrist skin (similar to project on any surface keyboards you might have already seen)

A camera in the wristband can tell what button is pressed.

There could just be a few buttons rather than a keyboad. The advantage is about twice the input area compared with an iWatch.
-- beanangel, Jan 19 2018

some images of projection keyboards https://www.google....projection+keyboard
[beanangel, Jan 19 2018]

There was a company that tried to get crowdfunding to do something like this - their watch was meant to project onto the back of the hand. Never got off the ground, because projecting an image onto an irregular and moveable surface at a very shallow angle doesn't work well.
-- MaxwellBuchanan, Jan 19 2018


Human skin doesn't make a very good projection screen, anyway. Even "white" people's skin is nowhere near white.
-- Wrongfellow, Jan 19 2018


The miniature hills and valleys of the wrist could make this one not work. I think green lasers are always green though. Weirdly, with enough computing you could adjust the emitted LED color blend to look right on any individuals skin.
-- beanangel, Jan 19 2018



random, halfbakery