A techy father has come up with a novel way of keeping an eye on his son as he walks to the school bus stop - a flying drone camera.

The 21st century solution to the time-honoured tradition of escorting children to the bus stop is the brainchild of Paul Wallich.

Called the Kid-Tracking Drone the hi-tech gadget uses a smart phone and chat software to record images from a lightweight 'quadcopter'.

The pictures are then beamed back to Mr Wallich's computer to give him a live view of his son as he walks the 400metres down the hill to catch the bus.

Once he is safely on board the flying machine hovers back to the family home, ready for another flight the following day.

Posting on the Inside Technology ieee site, Mr Wallich says: 'On school-day mornings, I walk my grade-school-age son 400metres 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.'

In order to ensure the helicopter flies close to his son a beacon has been fitted in the child's backpack which uses GPS to link up to an antenna attached to the quadcopter.

Mr Wallich has successfully used the device, but admits there are still some obstacles to overcome to make it efficient.

He said it has proved difficult to obtain batteries powerful enough to complete the flight when weather conditions are anything other than fairly flat, and wind has also proved to be a problem.

He added: '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.

He used open-source code to keep the helicopter stable in flight and to ensure it maintained whatever altitude the controller commands.

Back from the comfort of his home Mr Wallich can connect to a number of PC-based graphical user interfaces that overlay the quadcopter’s position and other data on a map in real time.

I am sure this won't be used for stalking someone.