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Tiny, Morphing, Electricity-Stealing Spy Planes Developed
tkohler writes "The Air Force Research Lab is developing an Electric Motor-powered Micro Air Vehicle (MAV) that can 'harvest' energy when needed by attaching itself to a power line. It can also temporarily change its shape to look more like innocuous piece of trash hanging from the cable. For domestic spying, maybe it will morph into a pair of sneakers?"
It's not made yet. I doubt even a prototype has been made yet.
Exactly. Magnetic charging like many "toothbrushes" and the like use inductors, so could these little things. That combined with flexible solar cells and there's no reason why these things would ever need to "come home".
"Growing old is inevitable; growing up is optional."
The guy has a point. At 11kv, water conducts and the design of insulators is a nontrivial problem. The idea of something like this deliberately flying into power lines will cause any power systems engineer to worry. Here in the UK, much of the country has significant rainfall, and fluctuating wind. I doubt it would be possible to fly reliably close enough to a power line to tap energy by induction, a small stray gust would take you straight into it.
Fortunately in the UK politicians are not allowed to add pork barrel projects to unrelated bills, the MOD is incompetent, and we have no money thanks to our wonderful banking system, so we won't be able to afford these things. We'll have to stick to cctv cameras that usually don't work, and people conveniently "losing" the results when they do.
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That's just a stupid urban legend. Shoes hanging from a powerline indicate nothing more than bored kids.
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actually if the shoes are in a gang's color it is their way of claiming the corner, usually for drug sales. a nearby gang would throw up one black and one red shoe tied together because those were their colors. that way other gangs and independent pharmaceutical salespeople are forewarned that they shouldn't set up shop on that intersection. if they do, they are asking to get shot. some gangs use it to claim the turf in general, but mostly it is used to mark drug spots now.
i used to teach in the 'hood and was educated by my students about it. obviously this depends on the part of town we are talking about
Cute idea. What they're trying to do, it seems, is mooch a little power from the electrostatic field gradient around the wire. This is quite feasible if you have a wire with a few KV to ground. The classic demo is to light up a fluorescent lamp by placing it vertically below a high tension line. This works partly because air is not a perfect insulator. There's an electrical path to ground; it just has a high resistance.
If the thing lands on an 11KV power line that's 10m above ground, and has a conductive part that dips 10cm below the line, it should see a voltage difference of about 90 volts. You can't draw very much current before the voltage difference disappears, but you can draw a little.
It's also possible to extract some energy magnetically. See U.S. Patent #3,202,963, "Apparatus for Illuminating Power Lines". But that approach requires heavier parts than an electrostatic approach.
There are no gay frat boys?
How much time does this thing require to spend on charging? The exposed powerlines it could latch onto are typicaly 11 kilovolts and up. It wouldn't require a lot of time to charge on those, so doesn it really need to diguise itself? Even if it looked like a pair of sneakers, the fact it flies in and out, might raise more suspicion than the look while charging. Also, the transformers required to take 11kv down to 220v for the house, aren't exactly dainty; how could this device step down the power with lightweight gear? (The power between the transformer and the home are in shielded cables, unlike the 11kv lines.)
FYI: In a typical power pole situation, you have three wires on top (in sort of a triangle config), and one part way down the pole. The top three are three different phases of the AC power, and the one part way down the pole is ground (you can see the occasional tap where the line is grounded to a stake in the ground). The step-down transformers for the home circuits tap into the ground, and one of the three phases, to give you 220v for several homes. (Factories and such will use all three phases for serious equipment.) Often on branch lines, only one of the three phases (and the ground) will be tapped off from the main line, to service some houses (with skinnier looking pole arrangements with only two wires). The fatter, insulated wires on the poles are cable and phone lines.
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