“My little piece of Privacy”, by Niklas Roy, is a robotic curtain which is too small for the window where it is installed. But since it is robotic and controlled by a laptop (running some processing code which does the computer vision), it detects the location of pedestrians outside and positions itself rapidly to where they are, thus not only blocking their looks inside, but also serving as a playful installation for people on the street. The rapid positioning of the curtain is done with a custom linear servo drive. It is basically a DC gearmotor which is controlled by an Atmega, programmed in AVR-GCC (as the Arduino-style-GCC performed to slow to handle the job). Processing code and AVR-GCC code are both on the page for download, as well as plans and schematics for building the linear servo.

http://www.niklasroy.com/