Father builds a drone to track son to his schoolbus

On school-day mornings, I walk my grade-school-age son 400 meters down the hill to the bus stop. Last winter, I fantasized about sitting at my computer while a camera-equipped drone followed him overhead.
 So this year, I set out to build one. For the basic airframe, I selected a quadcopter design for its maneuverability and ability to hover. Construction was straightforward: You can buy a quadcopter kit with all the pieces or, as I did, get parts separately and spend more time on system integration. 


On the mechanical side, there’s a central frame to hold the electronics, spars of aluminum to support the motors and propellers, and legs to cushion the quadcopter’s landing (I made a few extra sets of legs out of foam board for easy replacement). 


On the electronics side, there’s a main control board plus sensors, batteries, a power distribution board, power controllers for the motors (which draw tens of amperes, not what you’d manipulate with ordinary microcircuitry) and a radio receiver for standard remote-control flying, plus an RF modem for computerized control—I got both control systems for redundancy. 


To see the world from the quadcopter’s point of view, you can put together a fancy video-transmission rig, or just do as I did—strap on a smartphone and fire up your favorite video chat app. The motors I got can lift a few kilograms, but my surveillance drone’s total weight comes closer to 1 kilogram, for a good margin of maneuverability.