Networked surveillance minicopters can’t be kept down
Indoor flight requires a craft to be small, light and able to negotiate walls and other obstacles. “Reality bites you a lot more indoors,” says Zhang. But Sensorfly is too small to carry the technology it would need to look for and plan around obstacles. Instead it uses simpler strategies to survive.
Each robot carries a radio, accelerometer, compass and gyroscope. Thanks to the accelerometers it notices if it bumps into something, then backs off and warns fellow copters nearby of the obstacle’s approximate location. Any time two or more of the helicopters are within radio range, they form an improvised data network to share information. Their design is “passively stable”: as long as the twin rotors are spinning, the craft will hover in place. Its shape is such that if it is knocked to the ground, the craft need only keep trying and it should be able to get airborne again.
Squadrons of the craft connect with each other using radio. They pass information between themselves and back to a controller, and use the time delay on the radio signals to track their relative positions.
From NewScientist.com
[...] Networked surveillance minicopters can’t be kept down [...]