Summary explanation -- how it works:
Computers have been around for thousands of years if we consider the
abacus as a computer, and the abacus can be hung from a string,
worn as a necklace, or the like == an early "wearable computer".
But when we say "computer", especially in the context of
the "computer revolution" or the "digital revolution"
we usually mean a general-purpose computer that can run a wide variety of
"apps" (appliation-specific computer programs).
In this sense, the wearable computer was invented by S. Mann in the
1970s as a general purpose personal wearable computer system for such
applications as a seeing aid and as a photographic visualization
system for experimental and commercial photography
[Steve Mann, Campus Canada, ISSN 0823-4531, p55 Feb-Mar 1985,
pp58-59 Apr-May 1986, p72 Sep-Oct 1986],
and, more recently, for gesture-based 3D AR [Steve Mann,
IEEE Computer,
http://wearcam.org/ieeecomputer.pdf], and the smartwatch
http://wearcam.org/isscc2000.htm.
Wearable technologies represent a whole new field and discipline,
not just a single device:
"Steve Mann is the
perfect example of someone... who
persisted in his vision and ended up founding a new discipline."
-- -- Nicholas Negroponte, Founder, Director, and Chairman, MIT Media Lab,
1997
Many recent developments in wearable computing represent business
opportunities, in collaboration with inventor S. Mann.
A core element of this invention is the Digital Eye Glass,
and in particular, the
Extramissive
Spatial Imaging Glass, abbreviated "Spaceglass"
(see http://spaceglasses.com).
There are numerous business opportunties around this invention,
and working in collaboration with Meta in Silicon Valley California,
together with Meta's Chief Scientist, Steve Mann.
Another point-of-entry into this field is
with InteraXon, makers of the Muse, known as
"the most important wearable of 2014".