Silicon Valley is taking its penchant for programming to the skies.

Thanks to a proliferation of inexpensive sensors, chips, cameras and other gizmos that can be tacked onto wannabe spy planes and helicopters, it's easier than ever for technologists to build craft that fly themselves.

The techies are sending the three-to-six foot wide drones, guided by computers, radios and soon cellphones, to survey fields, capture action shots from the air or follow them around to snap photos at optimal angles. About their only constraints: a 400-foot ceiling for amateur drones set by the Federal Aviation Administration