Funny you should say that - when I was working @Intel I wrote a proposal for a Bluetooth Low Power ring that provide a simple input device for headless devices with 1 rotary input and one press input, sufficient to scroll and click on items.
Another proposal I had was a bracelet that would sense capacitance changes in the hand upon fingers touching each other; this way you could have a 12-key "keyboard" on the phalanges of the non-opposable fingers (3 phalanges x 4 fingers) touch-able by the thumb.
Such technologies would require minimal power input and provide good interaction with any headset; but at the time Intel were not interested in the research needed to build a prototype.
Another proposal I had was a bracelet that would sense capacitance changes in the hand upon fingers touching each other; this way you could have a 12-key "keyboard" on the phalanges of the non-opposable fingers (3 phalanges x 4 fingers) touch-able by the thumb.
Such technologies would require minimal power input and provide good interaction with any headset; but at the time Intel were not interested in the research needed to build a prototype.