Quora Question: Why Have Drones Suddenly Become a Big Thing?

An airplane flies over a drone during the Polar Bear Plunge on Coney Island in the Brooklyn borough of New York in this file photo taken January 1, 2015. Carlo Allegri/Files/Reuters

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Answer from Yuan Gao, engineer.

Several incremental advancements in technology, mostly focused on cost reduction, weight reduction (often both) or an increase in access to a particular component.

Take batteries for example. I remember a decade or two ago, the best batteries were NiCad and NiMH, which were too heavy to allow for small hovering drones (fixed-wind aircraft were fine however). Today, we have lightweight and energy-dense Lithium Polymer (Lithium Cobalt Oxide) that can provide enough power while being light enough to lift its own weight in a hovering drone. The battery weight issue is actually part of an overarching challenge to electric flight, it's why we're only just starting to see all-electric human-scale aircraft.

Hovering drones rely on an electrical stabilization system, which needs accelerometers and gyroscopes. Only in the last decade, and thanks in part to the smartphone industry, have low-cost MEMS accelerometers and gyroscopes been available, necessary for the stabilisation and AHRS system in drones. I remember only five years ago, a good MEMS gyro/accelerometer system would cost over $100; a decade ago it may have cost thousands; today we're talking less than $5.

Along with the sensors needed for stability, the drone also needs some processing power to calculate its orientation and process the sensor data. Microcontrollers have been around for a long time, but it's somewhat thanks to the maker movement that small, cheap but powerful microcontrollers have become more accessible to hobbyists. The barrier to entry to developing with these systems was lowered.

Hovering drones also need very powerful motors. But powerful motors tend to be heavy. It's actually relatively recently that small high-torque (direct-drive) permanent magnet brushless motors have become available to hobbyists. Maybe a decade ago, the best you could do (unless you were prepared to fork out a lot of money) were brushed motors with relatively weak iron magnets.

Along with the motors are the high power density switching semiconductors. Hovering drones use a lot of power, and this power has to be controlled (necessary due to the brushless motors). Only in the last couple of decades have FET technologies achieved high enough power densities and efficiencies to allow miniaturization of high-power rectifiers needed to run high-torque brushless motors.

Finally, also thanks in part to the smartphone industry, the advancements to the GPS system (the U.S. Air Force flipping a switch to enable higher accuracies for civilians; the launching of additional GPS satellites; the availability of SBAS systems, etc.) have allowed for higher accuracies and cheaper GPS modules. This is necessary for autonomous drones.

So despite there being no single technological breakthrough that made drones suddenly possible, it's a result of the compound effects of many incremental improvements in technology.

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Quora Question: Why Have Drones Suddenly Become a Big Thing? | Tech & Science