A simple and elegant way to help keep your personal space bubble from being invaded by close talkers and overly huggie people. This is a stolen or borrowed idea from Phillip Torrone of Adafruit, who mused about something like this on an episode of Adafruit's "Ask an Engineer." I decided to incorporate this idea into a bow-tie for all those black tie events that I'm forced to attend(no not really, it just seemed the easiest and most discrete way to incorporate the sensor). The jist of how it worked is as follows; If someone gets within 19" of me, red lights flash for a few seconds. If they stay there, the lights keep flashing. The distance and flashing rates can easily be changed to suite your needs if your personal bubble is larger or smaller than mine.
DSCN1778 from Aleksei Sebastiani on Vimeo.