I saw a talk at my university by a prolific robotics engineer who explained that for small drones designed to work by swarming & collaborating, it is much more

I saw a talk at my university by a prolific robotics engineer who explained that for small drones designed to work by swarming & collaborating, it is much more cost effective to use old Samsung Galaxy phones as the "brain" of a drone platform rather than integrating standalone CPU's. As far as I know they still use this as their primary design strategy.