| "What's the big technological driver that's allowed / caused this to happen?" As with most things, several things had to come together in order for this to happen. A probably incomplete list. 1) Lithium chemistry batteries - unlike Nickel, Cadmium, or Lead chemisty batteries, Lithium batteries are have a lower weight per watt-second than the others. 2) Micro-Electro-Mechanical-Systems (MEMS) - which is a technique for building a mechanical system (like a balance beam) using the same processes that create integrated circuits. This opened up developing accelerometers, gyroscopes, and magnetometers where the sensor and the conditioning circuit were all in the same silicon die. That hugely lowered the cost of such things, and has evolved to the point of providing 9 degree of freedom systems that are on one, or two inexpensive chips. 3 - Cheap 32 bit Micros - Emergence of inexpensive 32 bit microprocessors with DSP like features. The ARM Cortex M series in particular. Even with a cheap inertial sensor you need to process it fast enough and with enough precision to act. DSPs can do this but they are complex, difficult to program, and development tools are expensive. 32 bit ARM processors are easily engaged by high school students using off the shelf free tools. 4 - High performance MOSFETs (low Rds(on) resistance), cheap hall effect sensors - these allowed people to build brushless motors with atonishing power to weight ratios. From CD-ROM spindle motors putting out 1/2 HP for electric planes to 15W motors the size of pager motors which are quite light weight. Of course that all of this stuff is light weight gets the weight down to the point where you have enough power to lift it, and the integration gets the costs down to where you can build something on a small budget (a few hundred dollars, well within the budgets of active modelers) |
also, i'd love to know what the propellers are made of.
If it was me trying to film that close to a volcano, i'd simply use better lens :)