A nano quadrotor is simply a scaled down version of a quadrotor, a larger machine that uses the power of four rotors to levitate and fly. Roughly 8 inches (20 centimeters) in diameter, the nano edition weighs in at about 2 ounces (57 grams) and uses 15 watts of power. The machine hovers when all four rotors spin at the same speed and can move and change directions by varying the velocity of one or more rotor [source: Kumar].
The quadrotor's ability to pirouette through the air like a whirling dervish, dodging obstacles and navigating tight spaces, depends on both rotor speed and the rapid pace at which the robot obtains and processes information. Motion capture cameras tell the quadrotor where it is -- as well as where any obstacles may be -- 100 times per second, while an onboard processor sends commands to the motors in each propeller a whopping 600 times each second [source: Kumar].
What is truly remarkable about the technology, however, is the nano quadrotor's capacity to monitor its surroundings and coordinate with other aerial robots to act together without crashing into one another. The machines can literally come within inches of one another while maintaining stability. That means these miniature drones can draw on combined strength to lift objects together. For example, developers used an algorithm to tell a handful of individual robots which object to pick up, when to pick it up and where to do it, an exercise that resulted in a quadrotor-created tower [source: Kumar].
Outside the friendly confines of a laboratory, a quadrotor can familiarize itself with its surroundings using the motion capture camera and a laser scanner to essentially map out nearby features -- doorways, people, furniture -- and position itself accordingly in real time. The robot then monitors its own movements with respect to the features, using a kind of personalized coordinate system [source: Kumar].
You probably don't need a physics or engineering degree to understand that nano quadrotor technology is powerful stuff. Nor do you need to be a panic-mongering conspiracy theorist to have legitimate concerns about how it may be used. While developers, law enforcement officers and politicians have touted the potential of similar drone technology to change the way we live, some observers are also worried about the implications for personal privacy [source: Kumar].