FIELD A Fluorescent Array, Wirelessly Powered


What would you do if you were driving along the highway and you glanced into a field to see a giant array of fluorescent tubes lit wirelessly from the electromagnetic fields of power lines. Back in 2004, [Richard Box] set up this display after hearing about a friend playing “light saber” with fluorescent tubes under power lines. The tubes can be lit pretty easily by have a variation in voltage between the ends. By sticking one end in the ground and the other up in the air, he’s harnessing the strong magnetic field from the power lines. Though some thought the display was made to bring people’s attention to possible hazards of living near the lines, [Box] states that he did it just because it looked cool.

[via io9]

73 thoughts on “FIELD A Fluorescent Array, Wirelessly Powered

  1. “All i know is I’m not comfortable standing under those lines. God did not evolve me to conduct ac current or dc with out bad things happening. I’m not a doctor or a scientist, but I’m going to guess that microwave, xray,gamma,uv and all sorts of high frequency em radiation at low to high intensity is a bad thing in the long term. How high will the cancer rate go?”

    you’re obviously not a doctor or scientist because your viewpoint has absolutely no scientific rigor and it makes me want to facepalm a thousand times.

    first off, standing under power lines has nothing to do is conducting electricity or not. no, our bodies are not set up for being conductors and it can be fatal…but what the hell does that have to do with this topic at all??

    second, you’re not on the frontier when you decide that certain electromagnetic radiation is harmful when intensity is high…turns out that’s already widely proven by the atomic bombings of hiroshima and nagasaki. beyond that, if you have decided that all sorts of radiation in low intensity is harmful, then are you concerned about radio and television waves everywhere? if this was a legitimate concern then every person in europe and america should have cancer by now. we don’t.

    you have no idea how this works, you have no idea how the electromagnetic spectrum interacts with living organisms but you’re just going to assume it’s dangerous and causes cancer? that’s ridiculous. i’m not saying that they’re safe, but i’m not going to say they’re unsafe just because i’ve randomly decided so. have you ever been in a metropolitan area and felt “uncomfortable” standing on the street because all the high tension lines buried right underneath you? of course you haven’t because you have associated overhead lines with danger, so your response is emotional and irrational rather than logical and scientific. by all means, think high tension lines and their associated fields are dangerous all you want, but back it up with scientific reasoning and research instead of grainy b&w photos of power lines with post-rock playing in the background.

  2. @niun

    yes, that would be entirely awesome. you’ll likely have very jagged edges because of the cutoff of the tubes being reasonably high, but i bet the ones located in the stronger field would likely be more intense..whether or not it would be noticeable, i couldn’t make an educated guess so i won’t. i’ll just say it would be badass if it came out like that.

  3. For the people who thing this is stealing:
    The power company may start pursuit trees, fences, houses, tv antennas, etc in the path of the power lines, they are stealing.

  4. “For the people who thing this is stealing:
    The power company may start pursuit trees, fences, houses, tv antennas, etc in the path of the power lines, they are stealing.”

    That’s the reason why they cut corridors in forests for them and keep them cleared. The towers aren’t as high as they are just for fun – they have calculated how high they must be to minimise power loss and the expenses of building them.

    An interesting fact about HVDC lines: they create wind because the ionized air will move in one direction, instead of buzzing back and forth like with AC.

  5. Being an engineer, it seems that everyone has their own idea so I decided to go out & test what actually happened. Fluros are very strange things. If you just rub a fluro with a cloth, it will glow where you are rubbing it for a very short period of time (like about a 1/10th of a second) but not enough to notice if your not in the dark. This can be done anywhere (ie. not anywhere near HV powerlines [HVPL]).

    So I took my tube (1200mm long) and had a play under the HVPL (The HVPL were about 20-30m above me). It was very strange indeed because I could not get it to light up to start with by putting in the ground. After I had rubbed it and got it a bit glowing it worked by itself. Still it would never work with one end on the ground.

    So I was standing with shoes on under one of the extreme side HVPLs, holding the tube vertically with my left hand on the lower end and rubbing the tube with a cloth (actually a sock) in my right hand. To start with, it wouldn’t glow but after a while (about 10-20 rubs) it started to glow where I was rubbing. After about another 10-20 rubs it continued to glow even after I stopped rubbing. Once it was glowing (when I say glowing I mean that it glows noticably in the dark but nowhere near as much as normally in a house and you would not be able to tell it was glowing if you had a torch shining on the tube … quite dull in reality) I could just hold it up. Now it was really strange because if I just held it up verticaly with my left hand the whole tube would glow with the part near my hand the brightest and fading away from my hand to the other end (the other end was glowing but not as much). But if I then grabed the tube with my right hand (my free hand that had been rubbing the tube) about half way up, the glowing would stop in the part of the tube below my right hand. The top to the tube was obviously closest to the HVPL and still glowing. Removing my right hand caused the full tube to glow back down to my left hand as it was before I grabbed it with my right hand.

    Now I started to tilt the tube so it wasn’t vertical and tilted it perpendicular to the direction of the HVPL. The tube maintained its glow until a point when the tube was just inclined down so to say and the glow just stopped. Then lifting the end back up to make it more vertical it would then reglow as originally. I tried this several time tring to make sence of it all. It was strange because it would just cut out a that point just below vertical and you couldn’t make it slowly unglow so to say – very digital so to say.

    Next with the tube vertical I lifted it up higher as high as I could. It didn’t seem to glow any brighter or dimmer. Moving it back down so that my left hand, which was holding the lower end of the tube which was vertical, to about hip height. I then kept lowering the tube vertically and a really strange thing happened. When my left hand (ie the lower end of the tube) got to about 30cm (1 foot) off the ground, the glow in the tube stopped completely (ie. the whole tube). Lifting it back up a little (say 10 cm) the whole tube would reglow. Having said that I don’t know how our mate with the display got them to glow with one end in the ground.

    Next I walked across the HVPL corridor. As I stated previously I was under one of the very side wired (we’ll say the right hand one for convention). Holding the bottom of the vertical tube in my left hand (which was about hip hight) I walked away from the HVPL. The tube continued to glow until a point where again it just cut out (ie. no half glow as such … either on or off). The overall power coridor was 75m wide and this cut off point would have been about 10m from the edge of the coridor). Moving further away &/ lifting the tube up or down would not cause the tube to reglow. However moving back towards the centre of the power corridor caused it to reglow. Now I emphsise towards the center of the corridor because at point about halfway between the center wires and the side wires that I was originally under the tube stopped glowing again. There were 3 main lower wires on this transmission line. Each of these three was actually 2 wires separated by about 200-300mm or so. Standing under the very centre wire (ie. 2 wires) I couldn’t make the tube glow at all (except by rubbing it but it wouldn’t maintain it glow). However continuing my transition across the power corridor the tube suddenly reglowed at about a point halfway between the centre wire and the left wire. Continuing on, the tube stopped glowing about 10m in from the other side of the 75m corridor in a similar fashion to the other side of the corridor.

    Then I walked back to directly under the right hand wire (ie. where I had originally been standing) and the tube cutout as I passed under the centre wire & then reglow as I approached the right wire (same as previously) (note I didn’t need to rub or do anything just walk and the tube’s glow cut out & then reglowed).

    Now I inclined the tube parralel with the HVPL. A similar thing happened as when I inclined the tube perpendicular to the HVPL. At a point when the high end (ie free end) was just lower than the end that I was holding onto, the glow just stopped. Raising the free end caused the tube to automatically reglow. I repeated this several time with consitent results.

    Next, I held the tube nearly horizontal but so that the full tube was glowing. Then I grabbed the tube with my right hand about half way along. This time however the whole tube remained glowing although slightly brigher near my two hands. Releasing my left hand at the end of the tube caused the whole tube to glow. Now, however the tube was brighest in the centre (near my right hand) and faded towards the ends (although still noticably glowing at the ends). The region of the tube near my right hand was about half a bright as the region that was around my left hand when only my left hand was holding the end of the tube. Waving the tube as such with my right end caused the lower end to stop glowing from the right hand down as such and the top end (my right hand up) to continue glowing. Switching high end to low end would switch which end glowed. It was always the high end that glowed but the tube always glowed the brighest where my hand held it and faded to the high end.

    Thus ends my experiments report as such.

    So what’s my opinion. It’s the electric field variation (both distance away from the HVPL but probably more so the AC effect). The variation must be of a certain level to the electron valancey jump (remember high school chemistry) to make the glow although I really don’t know why the glow stopped at my hand when I grabbed it half way up. How exactly it works I have no I idea. My thoughts are that the air electrons (ie. those normal atoms outside the tube) are being constantly fluctuated in their valency states & it only that fluros have the property which causes the electron’s energy relese to form the visible light. Note I have read that neon light behave similarly around HVPL but obviously they aren’t a common. So I think that the energy comes from “wasted” energy as such. There is no induction in this system. I’m not saying though that an induction system (ie. wireless transformer) couldn’t be made to suck off electricity from the HVPL but I am saying that this whole fluro glowing thing really doesn’t seem to be inductance related but rather related to the varying electric field around the HVPL. NOTE: I was very skeptical that fluros could glow under HVPL prior to this little experiment. I hope this puts a little bit of reality into this discussion rather that all guessing & not knowing what actually happens in reality.

  6. I found this video clip which shows happens when you grab the tube half way up (see the last few seconds). I’d imagine that there is a HV line running above them or something to maintain the glow.

    Also a few other bits with my experiment yesterday. It didn’t matter whether I had shoes on or not. At several stages I took my shoes off to see what effect it would have and it didn’t seem to make any (ie. if the tube was glowing & it took them off the tube didn’t stop glowing or change its brightness & if it wasn’t glowing and I took them off the tube still didn’t glow).

    Another thing with rubbing the fluro with a cloth. You don’t have to press on the fluro very hard either. Once it starts glowing by rubbing it with a cloth, you can have the cloth drapped over you right hand and have your right hand in an arc (ie. not completely around the tube) so that the tube runs in the palm of you hand and then move the tube with your left hand. This way you only have the weight of the tube on your right hand (ie. very little weight) and move the tube with you left hand. You can also hold you left hand still and move your right with the cloth. I prefer holding the left hand still because then I’m not moving the tube and hence likely to hit something in the dark. Just a little bit safer so to say.

    Also weather condition when I was under the HVPL were just after sunset when it was dark. Naturally I was there early cuz I was eager to see what would happen. Minimal cloud cover and we have had no rain for the last week or so. In fact it has been quite cloudless for the past few days. The ground was reasonable dry with maybe just a little night dew starting. Temperature would have been about 23 deg C (a little colder than average air conditioning temperature so to say).

    Also, I drove the car under the HVPL holding onto the lower end of the tube with the tube basically vertical. The results were no different than when I was walking around. The cut off points were all about the same (ie. about 10m in from the edge of the 75m corridor and about halfway between the center wire and the two outside wires.

  7. Am I the only person that noticed the external source of light in the photo? all of the tubes have matching shadow patterns as if there is a flood light or something of the sort behind the photographer to the left. It seems as though the intensity of the tubes is exaggerated and partially due to reflection from that light source. Just a thought.

  8. Ok people…some of you need to brush up on your physics…

    This isn’t “stealing”!!! The powerlines put out these electric and magnetic fields ALL THE TIME. The thing that causes the glow is the flux between them…Its natural for this to happen. You are NOT using the electricity on the line to produce the glow…Its a reaction within the two fields. The power companies put these things in forrests and stuff so people won’t mess with them!

  9. smartazz … yes I had noticed the secondary light source. I would say that you would need a flash or some other light source so that you could see the tubes in the photo. I’m not sure that they would give off enough light to make a decent photo otherwise. As I said previously the tubes glow noticably but not very brightly. I’m guessing that if you had a medium sized battery torch light shining on a glowing tube that you would be able to tell if the tube was glowing or not.

    black/white … as i’ve been thinking about the “stealing” thing over the past week since the experiment I’ve come to the conclusion that all the phenomena is, is the excitation of the mercury vapour atoms in the tube by the electric field around the HVPL (obviously you may say). However, if the tube wasn’t there the air atoms would be excited anyway. The air atoms however release the energy as heat (or something other than light) [someone note previously that wind is generated around DC HVPL] where as in the fluro tube mercury vapour releases the energy as UV light as per a fluros normal operation. Either way the energy is absorbed & released (and not released down the HVPL).

    I’m also really think that the phenomena also occurs because the HVPLs are running AC so that at the peak voltage the electric field is exciting the atoms sufficiently and then at 0 voltage (as such) the mercury atoms have sufficient opportunity to release the absorbed energy (ie. in the form of light). If it were a DC electric field, there would be much less of an opportunity for the mercury atoms to release their absorbed energy as they would be constantly excited.

    Another possibility is that the phosphor powder on the inside of the glass (which normally absorbs the UV light and released visible light) is excited with UV rays from the HVPLs although I think that this is a less likely hypothesis.


    “I’m guessing that if you had a medium sized battery torch light shining on a glowing tube that you WOULDN’T be able to tell if the tube was glowing or not.”

  11. Here’s another clip of some guy … a little over the top but it shows how the fluro tubes glow under HVPLs.

    I’d say that the incandesant bulb has phosphor powder on the inside and that the phosphor atoms being activated by the microwaves (or some other frequency of the electrmagnetic spectrum). I can’t say that I can remember specificaly seeing an incandesant bulb that uses phosphor powder to convert the UV rays from the incandecant filament into visible light but I don’t see any reason why some “green” light bulb manfacturer wouldn’t build them. It is common knowledge that true incandesant bulb’s emit a lot of UV rays … that’s why they are “inefficient” (ie. because a lot of the energy consumed is used to produce so much ‘light’ that you can’t see as such rather than visible light).

  12. sajowe, the “digital” effect of the tubes that you experienced is the nature of the tubes themselves.
    They only give one level of light output, which is why you can’t connect them to a dimmer switch.

    Also it’s funny how many people don’t understand Faraday’s law of induction.

    Voltage = Negative change in magnetic flux over time
    There is a change in magnetic flux because the current is AC

    Electric potentials die away really quickly through air.

  13. mozotron – I am quite aware that you normally can’t dimmer fluros using a standard dimmer arrangement … however with the correct circuit you can dim them as I’ve seen it done. Actually it was about 10 yrs ago that I saw it done so I don’t think that its new technology.

    Secondly, you can dim fluros because how come they glow with much less brightness when holding them under the HVPL as opposed to when they are connected to the normal electrical outlet. Naturally it comes from what level of excitation the atoms attain before they release their energy. Thus, when holding the tubes under HVPLs the atoms are only just attaining enough energy to illuminate the tube.

    Now, what was interesting about this digital effect, which I think that you missed, was that the whole tube would tend to glow or not glow (ie. it wasn’t just the part of the tube that was within a certain distance of the HVPL thus dismissing the theory that the electrical voltage drop over the tube creates a current through the tube and thus cause the glow).

    Hence I’m not sure what you meant by the following because there is minimal (and I doubt if any) inductance of electricity into the tube.
    “Voltage = Negative change in magnetic flux over time”

  14. any electrical current flowing through a conductor produces a magnetic field perpindicular to that of the conductor, one end of the tube is planted in the earth, a ground, the high power lines generate large lines of magnetic flux which cut the top end of the tube, producing an electric current which causes light in the tube, and its not stealing, its using the magnetic lines of flux, which is a by-product of electricity, you pay for electricity, not magenetism, so essentially, we could field many of these through out the country, using the ‘free’ light as a solar energy source at night time

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