Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

UAV Hoisted Tower Powered By Laser Over Fiberoptic

timothy posted more than 3 years ago | from the want-one-for-the-block-committee dept.

Communications 103

carstene writes "LaserMotive, winners of the 2009 NASA power beaming contest, has a new invention, a virtual comm or surveillance tower. It's a quadcotper that can run indefinitely, powered by laser beam over a fiber optic cable. This allows the "tower" to reach great heights and avoids most laser safety issues."

Sorry! There are no comments related to the filter you selected.

Big boy toy (0)

Anonymous Coward | more than 3 years ago | (#36625848)

So, it's like one of those plane-on-a-string things that fly in circles? BuzzzzzzZZZzzzzzZZZzzzzzZZZzzz.

makes sense (1)

NEDHead (1651195) | more than 3 years ago | (#36625868)

take electric power from a cable, inefficiently convert to light, run it through a cable, inefficiently convert it to electricity, then use what little is left!!

Why not just use the electricity and a copper cable???

Re:makes sense (3, Informative)

Spazed (1013981) | more than 3 years ago | (#36625896)

Copper weighs more than a fiber optic cable.

Re:makes sense (0)

NEDHead (1651195) | more than 3 years ago | (#36626008)

Really? Can you cite a source that shows that, taking into consideration the energy density & adjusting for the conversion inefficiencies?

Re:makes sense (1)

Conditioner (1405031) | more than 3 years ago | (#36626762)

It's a know fact !

Re:makes sense (1)

djdanlib (732853) | more than 3 years ago | (#36626074)

Copper's resistivity would cause more energy to be lost after a certain length, too.

Re:makes sense (0)

Anonymous Coward | more than 3 years ago | (#36626208)

Fiber optics have attenuation and can only handle a certain power density before it melts. If it gets slightly damaged it will also increase the amount of local attenuation and will melt.

Not that this is a bad idea, but there are draw backs.

Re:makes sense (1)

BradleyUffner (103496) | more than 3 years ago | (#36626916)

Copper weighs more than a fiber optic cable.

Don't you still have to have additional cabling to support the fiber? I would expect that using plain fiber optic cable would break / stretch under it's own weight. I know my verizon Fios cable comes in bonded with a steel cable, and its just running in conduit in the ground.

Re:makes sense (0)

Anonymous Coward | more than 3 years ago | (#36627762)

I suspect they're using the cable only for power, and not for data. (Data would probably be via wireless.) If so, that means you can tolerate a lot more weird activity in the wire that could corrupt data but doesn't impede the energy-flow.

Re:makes sense (1)

Khyber (864651) | more than 3 years ago | (#36628134)

REAL GLASS fiber optics are heavier than copper cable, with the approximate atomic weight of copper being 29 and silicon dioxide being 30 having two oxygen atoms at 8 and one silicon atom at 14.

People that modded OP informative need to go back to basic chemistry class.

Re:makes sense (1)

Spazed (1013981) | more than 3 years ago | (#36628450)

Who said they were using glass? I've got two boxes of fiber sitting here, one glass and one plastic. Haven't touched the glass stuff in a few years, the bendability of the plastic just makes it a better choice. It is also about half the weight of the glass stuff. I would assume if this is meant for emergency or wartime use that it would be using the more forgiving, lighter, and more rugged plastic.

Re:makes sense (1)

Khyber (864651) | more than 3 years ago | (#36629098)

The plastic stuff is even heavier, (C5O2H8) for a total of approximately 54. Glass handles more power than pretty much every plastic given its lower thermal conductivity and higher tolerance to heat buildup.

Extremely thin glass fiber can be almost as flexible as a plastic fiber, and carry more energy.

Re:makes sense (1)

ketamine-bp (586203) | more than 3 years ago | (#36629518)

<quote>REAL GLASS fiber optics are heavier than copper cable, with the approximate atomic weight of copper being 29 and silicon dioxide being 30 having two oxygen atoms at 8 and one silicon atom at 14.</quote>

<quote><p>The plastic stuff is even heavier, (C5O2H8) for a total of approximately 54. Glass handles more power than pretty much every plastic given its lower thermal conductivity and higher tolerance to heat buildup.</p><p>Extremely thin glass fiber can be almost as flexible as a plastic fiber, and carry more energy.</p></quote>

atomic mass has little to do with the mass density of solid structure, for the matter. For plastics it is even a more complicated matter, even for plastics made of a single monomer, depending on the condition the plastic is formed there may be different density.

Your geek badge is herein revoked. not only that you should not tell others to go back to their chemistry class, it is you who need to go back to your high school physical chemistry.

Re:makes sense (1)

carstene (267166) | more than 3 years ago | (#36628830)

The key is not mass density, but unit of energy per weight. Turns out you and put more energy though fiber optic then copper for a given weight of material.

Re:makes sense (0)

Anonymous Coward | more than 3 years ago | (#36628850)

Says the douche who doesn't get the atomic weights right.

Re:makes sense (1)

Khyber (864651) | more than 3 years ago | (#36629074)

Atomic weight (approximate) matches the atomic mass, nimrod.

Are you so mad that you got owned that you had to reply AC to hide how mad (and wrong) you are?

Re:makes sense (1)

John Meacham (1112) | more than 3 years ago | (#36630266)

What does the atomic weight have to do with anything?

my gram of gold still weight much less than a pound of boron.

A cubic meter of oxygen weights a lot less than a cubic meter of lithium.

What matters is the energy density they can achieve, which has nothing to do with atomic weight.

Re:makes sense (3, Informative)

onkelonkel (560274) | more than 3 years ago | (#36626058)

Fiber is non conductive. If you are going to fly your little drone in a populated area, you don't have to worry about your tether contacting overhead power lines. A lot of cranes and hoists used to have fiber to the remote controls for that reason. (A lot of them are wireless now).

Re:makes sense (1)

NEDHead (1651195) | more than 3 years ago | (#36626174)

Hmm, good point. I guess we should add a 12 cent fuse to the circuit...

Re:makes sense (1)

vawwyakr (1992390) | more than 3 years ago | (#36626554)

Then you pop your fuse and lose your UAV?

Re:makes sense (2)

smelch (1988698) | more than 3 years ago | (#36626588)

Uh! No! Don't know you reading a 3 sentence paragraph qualifies all of us arm-chair EEs to know exactly where 12 cent parts can save billions for an application we know nothing about?!

Re:makes sense (1)

blair1q (305137) | more than 3 years ago | (#36627114)

Aside from the fact that us degreed EEs agree with him, you're right.

Re:makes sense (1)

pluther (647209) | more than 3 years ago | (#36628908)

A degreed EE should know enough about engineering to realize that not everything that goes into even something as simple as a power transfer system is going to be mentioned in a single paragraph.

Chances are a project that employed an entire team of engineers for months or years came up with a few ideas that aren't even in the article, let alone the summary. I bet some of them had EE degrees, too.

Re:makes sense (1)

smelch (1988698) | more than 3 years ago | (#36632714)

Well, that and it was a two sentence paragraph. Also, a driver can also be a back-seat driver. He just needs to be in the back seat.

Re:makes sense (2)

home-electro.com (1284676) | more than 3 years ago | (#36626258)

There is no such thing as non-conductive - all depends on the voltage applied. It will become very conductive once the lightning strikes it.

Re:makes sense (1)

jklovanc (1603149) | more than 3 years ago | (#36626658)

Should the sheath get wet due to rain or condensation it will be conductive. Also the conductor of power cables have a sheath of non-conductive material just like fibre optics.

Is the weight of the equipment required to convert laser light into electricity less than the difference between the weight of a ferrous conductor vs fibre optics. If the conductors were aluminum they may even weigh the same.

Re:makes sense (0)

Anonymous Coward | more than 3 years ago | (#36626806)

Flying requires a decent amount of power; you can't send lots of power over thin wires without either losing all your voltage, or melting the wires, or both. So a very, very thin fiber line carrying a powerful laser can replace a vastly heavier length of electrical wire.

And I mean heavy; if you had to pick up the bundle of electrical cable, you'd say "Damn, that's heavy"

Re:makes sense (1)

whit3 (318913) | more than 3 years ago | (#36626250)

You don't want to use electric power on a copper cable,
because of lightning. I'm thinking there will have to
be 'running lights' to warn aircraft at night, too.

Re:makes sense (1)

Anonymous Coward | more than 3 years ago | (#36626268)

Electricity -> light conversion by a laser diode is around 50% efficient. For a single wavelength, light -> electricity conversion efficiency isn't too far from the same figure. Thos gives a ~25% efficiency: not so bad, especially when you take into account the low power loss in hundreds of meters of thin plastic optical fiber compared to a long 2-wires copper circuit.

Re:makes sense (1)

Khyber (864651) | more than 3 years ago | (#36628152)

HVDC or HVAC are pretty much near-lossless for energy transfer, that's why they're used as California's primary energy transmission backbones.

Lightning strikes? (1)

way2trivial (601132) | more than 3 years ago | (#36628586)

fiber optic cables won't attract lightning?

(unless they are wet I suppose)

One drawback I see here... (2)

MAXOMENOS (9802) | more than 3 years ago | (#36625886)

...is that you have to retract the UAV during a storm. While it's retracted, you've lost the UAV's capability. So, I can see these deployed in emergencies when you need comms fast. But eventually you'll want to build a tower.

Another drawback I see... (1)

mdm42 (244204) | more than 3 years ago | (#36631218)

How are low-flying aircraft (always likely in emergency situations) warned away from the tether?

Atlantis (3, Funny)

lymond01 (314120) | more than 3 years ago | (#36625910)

Atlanteans had this tech back in the 10,000 BCs except they didn't bother with a tether, they just beamed their maser (that's Microwave amplified...) energy through crystals seated on top of large pyramidal buildings. We're so 20,000 years ago.

Re:Atlantis (1)

gstoddart (321705) | more than 3 years ago | (#36625988)

Atlanteans had this tech back in the 10,000 BCs except they didn't bother with a tether, they just beamed their maser (that's Microwave amplified...) energy through crystals seated on top of large pyramidal buildings. We're so 20,000 years ago.

Well, that's the problem with marketing ... sometimes "new and improved" means features everyone else has had for years. ;-)

(And, as anybody who has ever worked on a project to replace something on a mainframe can attest ... it'll be over budget, late, cost 10x as much as what you have now and require more compute resources, and never really do all that the current system does. It's amazing what people used to do with those things.)

And, slightly more on topic to your post, I honestly thought you were about to make a Stargate:Atlantis joke there. :-P

Re:Atlantis (0)

Anonymous Coward | more than 3 years ago | (#36626110)

Jack O'Neill: (looking out the window of a Goa'uld cargo ship on an asteroid approaching Earth) Carter... I can see my house!

Dear Slashdot code monkeys: STOP BREAKING YOUR WEBSITE YOU STUPID MORONS. We can't click on "Post Anonymously" unless we disable Javascript.

Re:Atlantis (0)

Anonymous Coward | more than 3 years ago | (#36626600)

Dear Slashdot code monkeys: STOP BREAKING YOUR WEBSITE YOU STUPID MORONS. We can't click on "Post Anonymously" unless we disable Javascript

Dear stupid Anon,

Just because you have to disable javascript to post anon, that doesn't mean that is the case for everyone so how about you put in a bug report?

  I seem to be able to post as anon with no difficulty.

Re:Atlantis (0)

Anonymous Coward | more than 3 years ago | (#36626758)

Just because you don't have to disable javascript to post anon, that doesn't mean that is the case for everyone.

I shouldn't need to post a bug report for something that used to work and is now broken. It's like these idiots modify their website and don't even test anything before putting it online.

Re:Atlantis (1)

Anonymous Coward | more than 3 years ago | (#36626966)

I shouldn't need to post a bug report for something that used to work and is now broken.

Yes, yes you do. At what other time would you put in a bug report? When stuff works and is still working?

Are you really this dumb?

Beside that though, in the FAQ is instructions on feedback and bug reports. I can almost guarantee that absolutely no admin has read your post or will read your post so you are only venting to your fellow /. readers who frankly don't give a shit that some anon is having problems posting anon.

Here, email someone who cares. help@slashdot.org

Re:Atlantis (0)

Anonymous Coward | more than 3 years ago | (#36627384)

I shouldn't need to post a bug report for something that used to work and is now broken.

Gold.

Re:Atlantis (0)

Anonymous Coward | more than 3 years ago | (#36627098)

riiiiiiiiiiiight..

Re:Atlantis (1)

atrain728 (1835698) | more than 3 years ago | (#36627190)

Ignoring the fact that there are no facts, your math is wrong.

Re:Atlantis (0)

Anonymous Coward | more than 3 years ago | (#36627578)

He said the 10,000s. As in, 20,000 BC to 10,000 BC. Well, 10,001 BC maybesince there's no year zero.

Re:Atlantis (1)

lymond01 (314120) | more than 3 years ago | (#36629086)

Hey, thanks AC. You're spot on. Atlantis had it in 10,000 BC and I'm saying our tech is probably what they had in 20,000(ish) BC.

What's next? (1)

TheMiddleRoad (1153113) | more than 3 years ago | (#36626062)

Hovering sharks with frickin' laser beams?

Re:What's next? (0)

Anonymous Coward | more than 3 years ago | (#36626098)

Sorry, we only got Hovering ill-tempered Sea Bass with laser beams working right now.

Re:What's next? (2)

OffaMyLawn (1885682) | more than 3 years ago | (#36626452)

Well, as long as they're ill-tempered. That's the important bit.

Old idea, commercially available now (2)

Animats (122034) | more than 3 years ago | (#36626072)

Tethered ground-powered rotor-lift platforms date back to WWII. Israeli Aircraft Industries [iai.co.il] has one in their product line today. They're usually installed on the back of a vehicle, so you can pop up the camera unit and take a look over the next hill. Early versions had no guidance and just used enough power to pull the tether taut. Modern ones fly actively, so they can be used to peek around buildings.

Using a fiber optic to transmit power is rather inefficient. Probably 70% - 80% of the power is lost that way.

Re:Old idea, commercially available now (1, Informative)

carstene (267166) | more than 3 years ago | (#36626186)

Main advantage of fiberoptic is two fold, first it is lighter then copper per unit of energy you can push through it. Second it is has no electrical resistance, so you don't get a huge voltage drop over long distances. What this means is you can have more payload at greater height then with a copper based electrical solution.

Re:Old idea, commercially available now (0)

home-electro.com (1284676) | more than 3 years ago | (#36626370)

Are you serious? You think the light goes unattenuated through the fiber? And power density? No way.

Re:Old idea, commercially available now (3, Informative)

carstene (267166) | more than 3 years ago | (#36626444)

Yup totally serious. Not plan old comm fiber optic, but consider how a laser welding machine pumps kilowatts though a correctly spec'ed fiber optic cable.

Re:Old idea, commercially available now (1)

home-electro.com (1284676) | more than 3 years ago | (#36626984)

Power lines however can handle megawatts.

Re:Old idea, commercially available now (1)

Nethemas the Great (909900) | more than 3 years ago | (#36627600)

Right and we'd also be speaking in terms of pounds per foot of cable.

Re:Old idea, commercially available now (0)

Anonymous Coward | more than 3 years ago | (#36629608)

Second it is has no electrical resistance, so you don't get a huge voltage drop over long distances.

Wrong, oh so wrong. Glass and plastic have enormous electrical resistance, so much so that they are considered excellent electrical insulators.

Re:Old idea, commercially available now (0)

Anonymous Coward | more than 3 years ago | (#36629878)

There are optical losses, especially when you're pumping that many photons down the fiber.
Additionally there's conversion losses at the aircraft. Might be better to just use open air beams, so you won't have to lift the tether that'll just get blown around.

How is this better than a balloon? (4, Interesting)

llZENll (545605) | more than 3 years ago | (#36626126)

Why not just use a balloon? The only advantage I can see this having is less movement due to wind, but designing a properly shaped balloon should easily defeat that, and more importantly a balloon would be much quieter at low altitudes, use much less power, and stay aloft even if the power is cut. Seems like a case of a hammer looking for a nail.

Speculating on advantages here (1)

MAXOMENOS (9802) | more than 3 years ago | (#36626182)

The fiber optic cable is the main advantage here. It gives you better data transmission to the airborne antennae. But in order to really facilitate that, the system probably needs better stability in wind than a balloon. (This is admittedly a SWAG.)

Re:Speculating on advantages here (1)

chemicaldave (1776600) | more than 3 years ago | (#36626416)

No reason a fiber optic cable cannot be tied to the balloon.

Re:Speculating on advantages here (1)

the_raptor (652941) | more than 3 years ago | (#36626606)

Apart from this little thing we call "wind". A quadcopter can compensate for wind in a way a balloon cannot (surface area is the balloons biggest weakness). Also for a 24/7 balloon you would need a pipe for lifting gas (Helium is a slippery customer) in addition to the one for powering the equipment.

Re:Speculating on advantages here (1)

M8e (1008767) | more than 3 years ago | (#36627000)

Hot air balloon.

Re:Speculating on advantages here (1)

SuricouRaven (1897204) | more than 3 years ago | (#36627056)

You could do without the pipe, if you allowed for a little maintainance: Someone gets to come around every week or so, haul in the tether and refill the balloon. It's not cheap though, and rather fragile.

Re:Speculating on advantages here (1)

llZENll (545605) | more than 3 years ago | (#36628888)

Both issues are easily compensated for: 1) wind, simply design a saucer shaped balloon with very low wind resistance, furthermore you could have a rotatable properly for exact positioning 2) simply store a small amount of helium on a tank which controls altitude

Re:Speculating on advantages here (1)

spydum (828400) | more than 3 years ago | (#36629556)

I have to agree -- dirigibles seem like a much more elegant solution -- not requiring a lift power source.

I mean, everyone talks about the power to send up to the copter -- but after that power is spent on lifting the damn thing, what power is left to do any useful work? communication towers, especially transmission towers require a fair amount of power all by themselves.

Re:How is this better than a balloon? (2)

carstene (267166) | more than 3 years ago | (#36626234)

Balloons get really big fast as you add payload. This means that more and more of your energy is used for station keeping rather then payload. Also with the UAV solution it is small and light enough to say fit in the trunk of a car and be handled by one person. For a balloon to carry any practical payload it is large enough where one person can no longer handle it on there own.

Re:How is this better than a balloon? (2)

home-electro.com (1284676) | more than 3 years ago | (#36626396)

But balloon would not make a news and it is so low tech. Lasers, on the other hand, are awesome.

Re:How is this better than a balloon? (1)

biek (1946790) | more than 3 years ago | (#36626504)

Balloons are extremely newsworthy if they may or may not have a tiny pilot

Re:How is this better than a balloon? (1)

Nobo (606465) | more than 3 years ago | (#36626404)

When they're both 1500 ft up in the air, a person on the ground can easily see the balloon it takes to lift 1500 feet of fiber and a sensor package, but can't see the spindly four-rotor helicopter it takes to do the same.

Re:How is this better than a balloon? (1)

juancn (596002) | more than 3 years ago | (#36626422)

I can think of a few:
  1. Size: A balloon with a decent payload has to be big, which makes it easy to spot from a distance. Check the name "InvisiTower", the idea is that this is smaller.
  2. Rapid deployment: Inflating and deflating a ballon is an operation that takes some time. A thing like this mounted on a vehicle can presumably be deployed in a lot less time with a single operator.
  3. Wind resistance: A large balloon is very hard to handle with even slight breezes.

There are probably other advantages that I'm missing.

Re:How is this better than a balloon? (1)

drinkypoo (153816) | more than 3 years ago | (#36631810)

Rapid deployment: Inflating and deflating a ballon is an operation that takes some time.

It takes less than one second to inflate a balloon with a compressed helium tank. The other things you've said make sense but this doesn't even come close. (You could also make the balloon transparent, which would reduce visibility.)

Remote safety, stability, and covert. (3, Informative)

Kamiza Ikioi (893310) | more than 3 years ago | (#36626474)

Because a balloon, at best, is filled with Hydrogen, and doesn't carry a lot of weight. This is for surveillance, possibly covert. Flying a giant balloon from a ground station in a forest outside a Colombian drug lord hideout wouldn't be the wisest move.

A copter on the other hand can be small, nearly silent, and left heavier equipment without nearly the visual footprint. It can also be rapidly deployed and returned for "quick looks". It can be taken to an exact height and location, not blowing around, and would not need tanks of gas brought around with it... A laser hooked up to a generator would eventually be safer and more portable and reusable in a battle or disaster.

It would also be much easier to remote control, turn the camera. What use is a balloon at say, a nuclear disaster zone like Japan, if the camera isn't stable enough to actually zoom in remotely without making the operator throw up?

Re:Remote safety, stability, and covert. (1)

SuricouRaven (1897204) | more than 3 years ago | (#36627066)

Hmm... could you make the balloon out of thin, transparent plastic for a tiny visual footprint? I know it'd leak out fast, but for an emergency battlefield comms relay a couple of hours might be all you need.

Re:Remote safety, stability, and covert. (1)

rossdee (243626) | more than 3 years ago | (#36627690)

"Because a balloon, at best, is filled with Hydrogen"

Baloons these days tend to use Helium, its not flammable. I guess a baloon would be easier to spot though.

Re:Remote safety, stability, and covert. (0)

Anonymous Coward | more than 3 years ago | (#36629804)

"Because a balloon, at best, is filled with Hydrogen"

Baloons these days tend to use Helium, its not flammable. I guess a baloon would be easier to spot though.

I think you missed GP's point - the very best case for lifting is to use hydrogen - you get about 8% more lifting power out of it.

http://en.wikipedia.org/wiki/Lifting_gas#Hydrogen_versus_helium

Re:Remote safety, stability, and covert. (0)

Anonymous Coward | more than 3 years ago | (#36632860)

Helium is heavier than hydrogen hence not an "at best" solution in terms of actual lifting capacity.

check your assumption at the door (1)

way2trivial (601132) | more than 3 years ago | (#36628732)

create a single molecule the size of your balloon, last stage of assembly, remove the gas molecules within.
(kinda like the pupeteer space ships, a single molecule of very large proportions.)
so long as it's strong enough to withstand the crushing force of the vacuum
Hell, use that really strong material known as aerogel.. either way, have the gap space be a vacuum

it would lift a hell of a lot more than hydrogen....

Re:check your assumption at the door (1)

John Meacham (1112) | more than 3 years ago | (#36630234)

Not really. Your lifting power can never be more than the weight of air it displaces and hydrogen is already a whole lot less dense than air. If you do the math a complete vacuum will only lift about 7% more than hydrogen. Even then I don't think there is any technology that will give us light containers that can withstand vacuum pressures of any usable size.

Re:How is this better than a balloon? (1)

Timmmm (636430) | more than 3 years ago | (#36626986)

Or you could simply have it land periodically and swap batteries. Much simpler I would think.

Re:How is this better than a balloon? (1)

R3d M3rcury (871886) | more than 3 years ago | (#36627704)

Besides the other comments, one interesting idea is that this is relatively small and unobtrusive.

A few years back, someone wanted to put up a cell tower. The complaint wasn't with the radiation or any of that. The complaint was that the tower was ugly and a destroy the local scenic beauty. While I certainly admit that I think five bars on my cellphone is pretty attractive, I can see the argument.

So something like this could be useful: A building with a fiber optic cable going up a few hundred feet to a small quiet helicopter might make a nice replacement for a cell tower.

Of course, the NIMBYs well find something else to complain about...

Re:How is this better than a balloon? (1)

Alex Belits (437) | more than 3 years ago | (#36629126)

...and the amount of energy, approximately the same as one going to the helicopter, is going to be dissipated as heat at the base of this contraption.

Re:How is this better than a balloon? (1)

hitmark (640295) | more than 3 years ago | (#36631630)

Re:How is this better than a balloon? (1)

Coren22 (1625475) | more than 3 years ago | (#36636024)

I have seen those along I-95 in MD, and thought they looked obvious, but a hell of a lot better than a bare cell tower.

wouldn't a balloon be cheaper? (1)

buback (144189) | more than 3 years ago | (#36626232)

What's the point of a heavier-than-air, tethered, actively powered, stationary platform?

Re:wouldn't a balloon be cheaper? (1)

Alex Belits (437) | more than 3 years ago | (#36629134)

Feed Lockheed, probably. It's not like anyone is stupid enough to use this outside of the US military.

Re:wouldn't a balloon be cheaper? (1)

Coren22 (1625475) | more than 3 years ago | (#36636034)

Maneuverability, size, weight, re usability.

why fiberoptic?? copper would work better (1)

lazn (202878) | more than 3 years ago | (#36626276)

Seems to me that a good copper wire and high voltage AC would be far more efficient and at a high enough voltage the wires could be very thin and still deliver loads of power..

Instead of converting electricity to light and back again, just keep it electric.

Re:why fiberoptic?? copper would work better (1)

nschubach (922175) | more than 3 years ago | (#36627046)

What if you never converted the light to electric in the first place. Just collect enough light from the sun and beam it into the fiber (assuming solar panels are too big/heavy for the drone...) I suppose the whole data transmission aspect of it would be quite a bit different in that case. It also wouldn't be as useful at night.

Don't forget the data (3, Insightful)

scrib (1277042) | more than 3 years ago | (#36626328)

One of the advantages of this design over a lightweight copper power feed is that DATA is bidirectional over the same optic cable. Transmitting the surveillance data back to the ground is much more secure and at higher rates than through thin copper or over some RF transmitter on the copter. That is, this can be stealthier.

Couldn't (1)

Dunbal (464142) | more than 3 years ago | (#36626350)

I couldn't seem to find any references as to the size of the payload this device can hoist up to 600 feet. I mean it's cute and everything but if it can't fly when you add a camera, exactly what kind of "surveillance" do you plan on doing with it?

Re:Couldn't (1)

blair1q (305137) | more than 3 years ago | (#36627162)

Re:Couldn't (1)

Khyber (864651) | more than 3 years ago | (#36628204)

Now can that 3 gram UAV lift about 60 pounds worth of cable to reach its surveillance height?

Re:Couldn't (1)

blair1q (305137) | more than 3 years ago | (#36628406)

That wasn't the question.

Re:Couldn't (1)

Khyber (864651) | more than 3 years ago | (#36629116)

It most certainly was implied.

"if it can't fly when you add a camera,"

Size/weight/power ratios are critical. That UAV of yours couldn't lift the cable attachment necessary for it to be powered AND fly at 100 feet at its current size.

Re:Couldn't (0)

Anonymous Coward | more than 3 years ago | (#36633928)

It could grip it by the husk!

Wireless? (2)

Sez Zero (586611) | more than 3 years ago | (#36626526)

I was actually hoping that wireless transmission of power didn't mean there was some sort of big cable connecting the transmission endpoints. But I see there are just no wires in the big "wire" that connects the drone to the ground.

Re:Wireless? (1)

blair1q (305137) | more than 3 years ago | (#36627220)

You are correct. This article is kinda stupid.

A laser beam without a fiber weighs nothing (in fact the photons have momentum which can be counted as lift at the receiver on the underside of the copter) and can probably be run at about 100X the power the lasers going through the fibers for this thing can. It also wouldn't be a serious contributor to the dynamics of the vehicle. 100 meters of fiber in any kind of breeze is going to add appreciably to the effects of wind and gravity, and form a huge reactive component in any motion induced by the vehicle. Good luck figuring out how to eliminate resonance when you're running near max lift in the first place.

They may have patented it, but they haven't proved it's worth a damn.

1 fiber (1)

bugs2squash (1132591) | more than 3 years ago | (#36628690)

They clearly only need one fiber to deliver the energy, but would need two copper conductors. I wonder if there's a way to deliver the energy over one copper wire.

Wireless indeed. (2)

fahrbot-bot (874524) | more than 3 years ago | (#36629686)

The critical factor behind InvisiTower is laser power beaming, which involves the wireless delivery of electrical power over long distances via laser beam ... In this case, laser light is beamed through the fiber optic cable and converted into electricity at the aerial platform.

Um. The phrase "wireless" must mean something completely new.

Re:Wireless indeed. (0)

Anonymous Coward | more than 3 years ago | (#36630484)

Well... Wikpedia defines wire as "A wire is a single, usually cylindrical, flexible strand or rod of metal", so yes, in that sense, it is without wires! (Emphasis mine). Of course, this does mean that 'two tin cans and a piece of string' is, likewise, a wireless communications system!

(However, Wikipedia also defines wireless as "Wireless telecommunications, is the transfer of information between two or more points that are physically not connected" - which isn't the case here.)

Maybe just use a wire? (1)

podom (139468) | more than 3 years ago | (#36630140)

Does one really save weight by transmitting laser power through an optical fiber versus using a lightweight electrical cable (maybe silver?) at a relatively high voltage? Even after the losses involved with converting the light back to electricity at the copter (probably about 50%)?

Serious question, is the power density of optical fiber really that high?

I've seen this technique used for sensors (http://spectrum.ieee.org/energy/the-smarter-grid/electricity-over-glass), wouldn't have thought it would work well for something like this.

Hmm, I wonder if the insulation is a design goal (1)

Marrow (195242) | more than 3 years ago | (#36630412)

maybe if the fiberoptic is a good insulator, it will be less likely to try to carry current to the ground and blow the helicopter and ground station to bits. This would make it safer in areas where there are power lines. It also might make it safer when the weather is not so nice.

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?