Wallich shared the details behind his design with engineering magazine IEEE Spectrum, but the project is actually a pretty simple one — the copter is a fairly standard build that Wallich got airworthy easily. Getting the gizmo to follow his kid was a little more tricky, as an RFID solution would have necessitated a burlier antenna than the small craft could comfortably carry. Instead, Wallich used a navigation program that kept the copter a set distance away from the GPS beacon it was following. He even strapped a camera unit to the thing for full eye-in-the-sky capability.