Free electicity - crystal radio

  • Thread starter rcgldr
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  • #1
rcgldr
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Since the last thread got locked, how about legal means to get free electricity?

One example is an AM crystal radio that receives it's power via a simple antenna. The power source is a radio stations broadcast.

As posted previously, there are numerous devices like windmills or water wheels, solar converters that can generate electricity but it costs money.

The example I posted about a device that moves along a high tension high voltage line is used by owners of these lines for inspection purposes. Since it's their electicity, it's legal to do this. The interesting thing is that these devices work off a single line.
 

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  • #2
berkeman
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But don't the crystal and whisker contact and the antenna wire cost some money? How free do you want free to be? Lemons and copper cost a little bit of money as well (or however you make a home-made battery).
 
  • #3
rcgldr
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True, since the original post didn't mention anything about the quantiy of free electicity to be obtained or the cost of the device to produce the electricity it's hard to say.

Lemon battery uses copper (penny) and zinc (some nails):

http://hilaroad.com/camp/projects/lemon/lemon_battery.html

At the other extreme, a person could pay a huge sum of money to find and retrieve the power unit from the lunar module from Apollo 13 that's at the bottom of some ocean. Since it's a simple composition of plutonium buttons and thermalcouples, it's got a lot of useful life left in it. Plus it would be a collectors item.
 
  • #4
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STATIC----gimme some static, guys




...(or girls)


(static electricity)

---------------------------------------------

One of the more interesting 'things' I like (eg--the radiometer for another one) was seeing (on a TV program) a device used in remote areas of Russia/Siberia. It was a doughnut shaped device (it looked like a set of coils) that fit down over the chimney of a kerosene oil lamp and it somehow generated enough electricity to power a small radio.
 
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  • #5
xez
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Wind generators work well in many areas;
photovoltaic systems work well too.

An exercicse bicycle hooked to a generator works well,
as long as you keep pedaling.

A nice hot cup of tea hooked to an infinite improbability
generator works well, but there can be other problems
encountered with that setup.

A tall lightning rod hooked to some 0ga cable going into
your house can work well, at least if you use your power
in brief spurts. :)

Scuffing about the carpet and then touching your
computer case could work in theory, but it has its
disadvantages.
 
  • #7
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i laughed unbelievably a lot with berkeman's post in https://www.physicsforums.com/showthread.php?t=177467".

lol... i specifically said not by stealing.

Thread locked. Defrauding the power company is a crime, and we won't help you do that. Your professor should get reprimanded for his/her actions.

PS -- please point out to your professor that the newer electric power meters are able to detect his kind of hacks, and the power companies definitely pursue those people that try to avoid some or all of their electric bill. The company that I work for is becoming a leading producer of these new smart electric meters, BTW.

i said in that thread that it was A) for class and B)anything that's not illegal

although i wouldn't mind him being "reprimanded" since i don't like him... but my intentions were for my class and grade... i don't even pay for the electric bill...my parents do

True, since the original post didn't mention anything about the quantiy of free electicity to be obtained or the cost of the device to produce the electricity it's hard to say.

Lemon battery uses copper (penny) and zinc (some nails):

http://hilaroad.com/camp/projects/lemon/lemon_battery.html

At the other extreme, a person could pay a huge sum of money to find and retrieve the power unit from the lunar module from Apollo 13 that's at the bottom of some ocean. Since it's a simple composition of plutonium buttons and thermalcouples, it's got a lot of useful life left in it. Plus it would be a collectors item.

that actually seems pretty interesting... possibly plausible for the answer he is looking for... i would convey that that idea to him but unfortunately we as a class have only 5 chances...2 of which have been used by the idiots of the class on elementary anwsers...so we really have to make the answers we give count.
 
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  • #8
Danger
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Lemon battery uses copper (penny)

Well, this one will cost at least 1¢. :rolleyes:
 
  • #9
mgb_phys
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I use this as an interview question for new engineers.
"describe some ways of powering a device out in the woods"
Start off with the obvious diesel generator/solar power then rapidly descends into turnstiles at the entrance to rabbit burrows or piezo crystals under eagles nests - a good way of seeing how far "outside the box" they can think as well as their knowledge of physics.

ps. If the OP doesn't understnad why the original thread was blocked - it is possible to fool old style 'clock' electric meters by << hint removed by berkeman -- sorry >>

You can quite legally take as much pwer as you want from a phone line as long as you don't take it off-hook. Maxim make a chip which will automatically monitor the line and draw as much current as possible, very useful for powering remote monitoring devices. If you are at the end of a long boosted line in the countryside you can get a 100mW this way.
 
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  • #10
berkeman
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i laughed unbelievably a lot with berkeman's post in https://www.physicsforums.com/showthread.php?t=177467".

lol... i specifically said not by stealing.

i said in that thread that it was A) for class and B)anything that's not illegal

Glad that you got a good laugh out of it. That's what we're here for, after all.

Honestly, it still sounds like your prof is referring to the classic hack of an electric power meter (which is very illegal). But if the requirement really is that it be legal, then the only way that I know of is to capacitively couple some energy off the high voltage power transmission lines. You don't get much power, and you have to be on public or private land (that you own or where you have written permission to be there), and not on power company land. You can calculate how much power you can receive by researching the AC voltagees that are used by HV transmission lines, how far above the ground they are, and what kind of capacitances you can acheive with practical size coupling arrangements. You probably can't put your couplers more than a meter or two off the ground and stay legal, but I don't know what all the legal ramifications are.
 
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  • #11
russ_watters
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I thought it was inductors people used for that, but that's still stealing.
 
  • #12
berkeman
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I thought it was inductors people used for that, but that's still stealing.

Is it? I guess it might be. Maybe I should lock this thread now too? :rolleyes:
 
  • #13
mgb_phys
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I always wondered about this - if I stand near a powerline in conductive shoes on wet grass am I stealing? It's like walking under a streetlight wearing black clothes !
 
  • #14
rbj
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if you're gonna "steal" or pull "free electricity" outa radiation in the air, why not a solar cell? whether it's a solar cell or a crystal radio or one of these reputedly illegal ELF couplings to big-ass power lines, the only difference is the source and the transducer.
 
  • #15
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it still sounds like your prof is referring to the classic hack of an electric power meter (which is very illegal)
That is such a simplistic interpretation. :grumpy:

This type of riddle is a pretty classic means of extending brighter students. Possible answers include:
- thermal energy. :smile: Without any knowledge of the particular course content, this would be my choice because this energy is freely available and practically limitless; the question did not specify low entropy content (work capacity).
- common or obscure renewables (eg. solar or atmospheric pressure variations), which can provide more than enough power as to reimburse the initial costs.
- fossil fuels. For practically zero financial cost, with these you can take millions of years of concentrated solar energy.
- some pop-culture reference. Usually the point of the puzzle is to keep the students engaged (and it appears to be succeeding); it isn't necessary for it to have any (relevant) answer!

You probably can't put your couplers more than a meter or two off the ground and stay legal
Now you're saying that it is ok to steal electrical power, if you make it look subtle enough!?!?

Maybe I should lock this thread now too?
You jest about your own heavy-handed behaviour? :yuck: The OP of the previous thread specifically said that the solution must be legal, and you locked the entire thread because of only one off-topic post!!

And even in the case of that single post, the legality is in your interpretation. The means is interesting in itself (there is an entire forum here for discussion of nuclear physics topics, even though much of that would be illegal for most people to apply), and it is perfectly legal in many contexts (perhaps a valid answer is any novel method to capture a few microwatts of power that another of your wall-socket appliances wastes as 50Hz EM radiation).
 
  • #16
berkeman
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That is such a simplistic interpretation. :grumpy:

This type of riddle is a pretty classic means of extending brighter students. Possible answers include:
- thermal energy. :smile: Without any knowledge of the particular course content, this would be my choice because this energy is freely available and practically limitless; the question did not specify low entropy content (work capacity).
- common or obscure renewables (eg. solar or atmospheric pressure variations), which can provide more than enough power as to reimburse the initial costs.
- fossil fuels. For practically zero financial cost, with these you can take millions of years of concentrated solar energy.
- some pop-culture reference. Usually the point of the puzzle is to keep the students engaged (and it appears to be succeeding); it isn't necessary for it to have any (relevant) answer!


Now you're saying that it is ok to steal electrical power, if you make it look subtle enough!?!?


You jest about your own heavy-handed behaviour? :yuck: The OP of the previous thread specifically said that the solution must be legal, and you locked the entire thread because of only one off-topic post!!

And even in the case of that single post, the legality is in your interpretation. The means is interesting in itself (there is an entire forum here for discussion of nuclear physics topics, even though much of that would be illegal for most people to apply), and it is perfectly legal in many contexts (perhaps a valid answer is any novel method to capture a few microwatts of power that another of your wall-socket appliances wastes as 50Hz EM radiation).

Well, you bring up some valid points, cesiumfrog. And I've read enough of your posts to have some respect for your opinion, so let me offer some response points.

The other thread's OP's OP sounded fishy to me:

Hey everyone. I'm taking physics 2 right now in the summer and my professor keeps saying you can get free electricity, but doesn't tell us how. He's pretty stuck up and has been saying this since class started 3 weeks ago. It's really annoying and as a class we want him to shut up. Well, that's a part of it. He says if any one of us get it right, he will boast each persons grade by 40% and we sure as heck need that cause our class average of 36 people right now is 46%.

Unfortunately, though, nobody knows the answer to getting free electricity in class and some people have tried searching for it but have been unsuccessful. Well, we have found some "free electricity stuff" but it's not really related to Physics 2, like the professor said. Also, none of the other professors know either.

Here is where I (and the class) turn to you, the good people of Physics Forums. How in the world do you get "free electricity"?

And I have to admit, that in the OP's follow-up post, I missed where they said that they did not want illegal ideas:

sorry, i forgot to include that. he's not saying free in terms of free energy like in gibbs free energy from chemistry or anything.

he's using free in terms of money. free meaning you don't have to pay for it. and not by any illegal means like stealing, lol.

So think of it like this: "How can you get electricity and not pay for it?"

He did not give us any hints, but I know we get electricity from electrons. My guess is we have to generate them somehow, but thats where I get stumped and question my idea, as to, "how could we do it without paying for it"?

I saw, "free in terms of money", and thought straight away about the classic meter hack (which is used by some professors as a teaching tool, BTW).

When I tried to think of some legal method in this extended thread of getting "free" energy, the only practical thing that I could think of was the obvious example that I listed. I honestly don't know if it is illegal -- it sure seems pretty benign to the power company if you don't encroach on their legal right-of-way. If I put up a couple flat conductors on my own land that the high tension transmission line goes over, I'm just tapping into energy in the transmission line that is lost into the ground anyway. That's fundamentally different from << illegal technical advice deleted by berkeman >>.

Anyway, when I locked the other thread, I of course reported it to the Mentor forums, where it was reviewed by the other Mentors. So far, I haven't been thumped for that action. But, I'd like to recommend that if other posters feel the same way as cesiumfrog (and obviously the original OP), please report this post of mine, to get the Mentors to revisit my action. That's not necesarily a bad thing for me -- I've been corrected or redirected several times in my Mentor duties here on the PF.

But let's all keep one thing very clear. This is a technical forum where we get several hits per week from people trying to do things that are illegal or dangerous or otherwise bad, and most of you do not see that. The Mentors try our best (on volunteer time) to clear that junk out. And the OP thread was at best on the margin of a useful/legal discussion, IMO.
 
  • #17
berkeman
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Okay, my re-report of myself to the Mentor forums has resulted in some constructive criticism. I think that the best way to move this forward would be for me to talk directly with the professor who has posed the original question, in order to understand several things about the context of the original question. I've PM'ed webdivx to ask for a contact with this professor.
 
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  • #18
berkeman
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Except, how do I get the professor's contact info without potentially compromising webdivx's standing in the class? Rats.
 
  • #19
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Different question:

If I put up a couple flat conductors on my own land that the high tension transmission line goes over, I'm just tapping into energy in the transmission line that is lost into the ground anyway.
Is that true?

Is power really being lost just into the ground, and if so can it be claimed without increasing the amount of power that the line loses?

I don't see why there would be any fundamental problem in taking power by wrapping great lengths of the power transmission lines with your own wires, if this only captured power that would have been lost into the surroundings anyway. I'll presume that you own those surroundings, that your wiring is demonstrated to meet safety standards and not cause an eyesore or similar problems. (Of course, if such a thing were economically feasible, wouldn't the company have already done it?)

The naive method seems exactly equivalent to a (stretched out) transformer, and it seems inevitable that increasing the loading (the power you take) will increase the power that the line loses more (compare http://ecmweb.com/news/electric_overcoming_transformer_losses/" [Broken], which also ends with an interesting sidebar pertaining to consumerism vs environmentalism). I'm not sure offhand of the basic physics that explains this, but at any rate it is still conceivable that an alternate method would capture only the power that would still be lost regardless. (For example, surely a crystal radio only extends a shadow over part of the radio wave, rather than actually increasing the power that the transmitter uses.) Ideas?
 
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  • #20
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Well what is that lost energy? Thermal energy? Probably not magnetic since, as you said, putting a coil around the line and using that would load the power line. What else is "lost" other than I2R losses?

By the way, they did that on MythBusters (a giant coil next to a powerline). I think they got about 8 mV. :rolleyes:
 
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  • #21
berkeman
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I'm thinking in terms of capacitive coupling. And yes, as far as I can see, you are not adding any load to the transmission line above the existing losses. However, the power company could argue that the "free" energy that you are tapping out of their existing losses are then making it so that you purchase less power from them, so I guess they could make an argument that tapping their existing losses deprives them of revenue.

BTW, you can see the capacitive effect pretty easily with just a DVM. Stick one lead in the ground and hold the other up (DVM set to ACV). Do it a ways away from the power transmission lines, and do it underneath them.
 
  • #22
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Theres no problem berkeman. I found the answer! Here is the story:

I got the class together before it started on Thursday to propose my answer and showed them http://www.technologyreview.com/Nanotech/16746/" [Broken] and they although hesitant, gave the ok. They said I should give the professor the answer and I agreed. I walked into the class, with the class walking behind me (I felt so cool...lol) and said that we have the answer to his question.

He said "oh really?". And I said "ya". "The way to get free electricity is from human power, to just do day to day activities normally. But it doesn't stop there. Although this technology isn't fully developed, that electricity can be harnessed into making things like our IPODs work using nano wires."

And then he said "You must be kidding, right?" So I said "no, look at this" and gave him the article. He looked at it and was like "Get out. Class is dismissed". And everybody is like "what the..??" All eyes are on me like I did something wrong. I told everyone to chill and see what happens tomorrow (Friday).

So Friday comes and everyone is glaring at me before class starts (friendly class, huh? there the ones that agreed to it). He comes in 5 minutes late with what seems to be a pile of thick packets. He hands one to each of us and tells us this is a test and we must do it page by page within the hour and not skip forward. I look at the page and it's like crazy hard, but I get through it (with all the wrong answers I'm sure). Page 2 and 3 same thing. But then.. on page 4 it says
"This test does not count. (go to page 5)"
"Congratulations! (go to page 6)"
"40% (go to page 7)"
"Add that to your grade".

And I look up with the teacher staring at me with a smirk on his face. I look around the class and eventually other people are flipping through the pages too until he just gets up and says "You can thank... and points toward me. The rest of the people of the slower persuasion all flip through the pages all quickly as I hear "dude you rock!!" and "you own" and several other compliments which i couldn't make out since the (hot) girl behind me was squeezing me to death (she was happy)

after like a few minutes of celebration he throws down our physics book and tells us that it's time to get back to work. so the rest of the class goes normally and the day is over so as i'm leaving everyone is all coming toward me and thanking me with hugs, pats on the back and handshakes as well as a whole bunch of comments i couldn't make out since they were all talking at once.... at the end i finally got to my car feeling like I just hit the winning shot in the NBA Finals or something and actually am looking forward to Physics class on Monday.
 
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  • #23
russ_watters
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Congratulations, but I find myself having a hard time trying not to insult the guy. The question was poorly conceived and the answer would be obvious if not for that. And your answer, though a different technology, does fundamentally the same thing that self-winding watches have done for decades: http://electronics.howstuffworks.com/question285.htm
 
  • #24
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Congratulations, but I find myself having a hard time trying not to insult the guy. The question was poorly conceived and the answer would be obvious if not for that. And your answer, though a different technology, does fundamentally the same thing that self-winding watches have done for decades: http://electronics.howstuffworks.com/question285.htm

ya he's not really a great guy... i don't even know if that was the exact answer he was looking for, but it was right since he was so vague

and oh yeah...kinetic watches? thats also like free electricity and is sort of like the same concept as the nanotechnology stuff
 
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  • #25
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I do not believe that story. *shrug*
 

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