I built the "Lightcomb" back in the 1970s, which evolved to this system of the early 1980s (completed 1981). To the best of my knowledge, this was the world's first true "wearable computer" (e.g. the first wearable device into which program instructions could be entered and then executed while walking around, as opposed to merely a wearable timing circuit, or the like).
This very same lightcomb was used in commercial photography as recently as mid 1980s (including its use in the production of a full page hair ad in IMPULSE), and was also known as the Sequential Wave Imprinting Machine (SWIM) when programmed for the generation of sinusoidal or helical wavelike patterns.
It may look a bit cumbersome (recall that this is something I built back in the 1970s). Using more modern technology, I built a number of smaller units in the 1980s which were used with WearComp4.
The above close-up picture shows the 1970s input device, which is quite similar to the input devices I continued to build into the handles of electronic flashlamps in the 1980s. The input device allows the wearer to type commands into the computer, or program it while walking around.
A lightcomb may be used to capture pictures with structured illumination, or to write messages in the air, during long exposure pictures (or by virtue of the persistence of vision). A miniature version can also be built using a row of LEDs so that you can type messages while swinging it through the air, and create text, graphics, or structured light.