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Microwind Generator - any one up for the job? Answered

Microwind Generator: 30X More Efficient and Cheaper!

Popular Mechanics just held it's yearly Breakthrough Conference, and one of the winners was the Wind Belt an invention we've not seen before. The Wind Belt

http://digg.com/general_sciences/Microwind_Generator_30X_More_Efficient_and_Cheaper



Seems pretty simple!

Anyone willing to make this?

Things you might need... fabric, Neodymium magnets, and coils

You can easily get good coils from led generators, even from the crappy 2 dollar ones. (As long as pumping it makes the led light on.)

50 Replies

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rbuzarang (author)2012-08-03

Someone please tell me where to get Mylar Coated Taffeta...

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Plasmana (author)2010-03-21

That is a very nice idea, I will give it a go sometimes soon!

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robotkid249 (author)2010-03-19

BTW I made one and it works very very well.

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johnnyreub (author)2009-11-10

I put one together, using gorilla tape.  see full details here:

http://buildingstuffinthebasement.blogspot.com/2009/11/diy-windbelt-with-wood-and-duct-tape.html

nothing like the nail-breaking power of mylar, but this seems to work well enough to light up led's in ~ 7mph wind

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JeffBach (author)2009-05-10

This is one of those seemingly simple projects which has HUGE devils in the details. For me and my daughter as we do (try to do) this for her science fair, the killer part is the belt and its movement. Pretty much like S Frayne suggests in his post here. Right now, from my frustrated Dad point of view, if I can't get this working in a fairly controlled environment with a steady wind source from a known direction, I really can't see how this could ever be made robustly enough to handle the myriad of environmental conditions that a commercial unit, deployed in Haiti, would encounter. We can get some movement of the belt, but still not (apparently) quite right, as there is a bit of sideways motion in addition to the vertical movement of our magnet as it rides up and down on the belt itself. All the basics are unknowns or at least "unproved" - 1. how long to make the belt, 2. how wide to make the belt, 3. the tension on the belt, 4. one magnet or two (both riding the magnet, one above and one below the belt), this does change how the belt moves of course..... 5. distance of fan from belt 6. angle of moving air onto the belt 7. does a craft store magnet lack the strength of a rare earth magnet and so is wrecking our project because it lacks the required strength? 8. how close do the coils need to be from the magnet? 9. If I attach the coil to the bracket with plastic and a cable tie does that somehow detract from the generation? I don't think so, but I've never worked with such tiny amounts of juice before either. However, each one of these does provide a teachable moment so all is not lost. But my kid is still pissed that the project I convinced her to do is not yet working :( Notice how I really haven't even mentioned the electronics part? Solely because the belt apparatus is so touchy and sensitive. I love the idea. I love what he has done with a so-called educational policy. To my chagrin though, even acknowledging the elementary level I am at, I find this device is just too sensitive to too many parameters to ever be able to handle a real world setting. Frustrated but still intrigued by it - Jeff

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Phil77 (author)2009-01-13

hello all, i noticed this thread has been dead for quite awhile and I was wondering about, Steve how the project has been coming? In-peticular I was wondering if you could provide me with the electrical frequency of the output of the 45.5cm wind belt, as I am attempting to test one of my own however I could not find any specific specs on your website. I wish to work backwards mathematically to find the frequency at which the band must oscillate to produce the same results as you.... Is this indeed practical? Or would it be more beneficial to just begin from scratch?

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Kiteman (author)2007-10-13

What a brilliant idea!

I'm not sure it's a solution to many actual problems (as one comment said, a hand-generator will provide much more power, much more quickly), but I would like to see this as a fence or screen - say, strung between the railings around a balcony or roof-garden and running a small sonne et lumiere installation, maybe with the music changing with the wind-speed.

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gizbiz (author)Kiteman2008-10-05

That sounds like a marketable idea. Why not?

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guyfrom7up (author)2007-10-17

yeah, you have to get the perfect angle of wind and just the right tensions. If you add a fin though it would add to the cost because then you need ball bearings

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Kiteman (author)guyfrom7up2007-10-17

Make a set of them pointing in several directions, say eight in a circle at the top of a mast.

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gyromild (author)Kiteman2007-10-17

But that will be somewhat inefficient, since only some of them will be working at any given angle. Perhaps a rotating mast?

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gizbiz (author)gyromild2008-10-05

A rotating mast won't work with a hard wired arrangement like this. One full turn would ruin everything.

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Kiteman (author)gyromild2007-10-18

Given sfrayne's comments about angles of attack, and the fact that the wind would be blowing through both opposite sides of a ring of windbelts, I'd say that about half the windbelts would be running at any one time. Adding a rotatin mastincreases the complexity and adds moving parts, something sfrayne was trying to avoid.

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gmoon (author)Kiteman2007-10-18

I'd say that about half the windbelts would be running at any one time.

Or two stacked half-rings (smaller footprint.) As noted, these work equally well from the opposite side.

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gmoon (author)gmoon2007-10-18

How about a 'signpost' mount?

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NachoMahma (author)Kiteman2007-10-18

. Sounds to me like both of you are right - just depends on what you're trying to accomplish. If you want maximum efficiency and output/size ratio, it seems to me that one large, rotating MWG would work best. If you want stick-it-in-the-wind-and-it-works operation with lower maintenance costs, then the ring of smaller MWGs sounds better. . In the ring design, would the "shaded" (out of the wind) MWGs put a load on the system? If circuitry has to be added, it will increase the complexity - although probably not as much as a turntable.

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Franx (author)2007-11-01

gyromild says: "Just curious, is there any particular reason that the coils are placed on only one end of the belt instead of both?" I'd also like to know the answer to this but I can't find it above. sfrayne??

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gizbiz (author)Franx2008-10-05

There are more than the one pic of these devices. One shows coils at both ends inside an aluminum bracket arrangement with the aluminum acting as the belt tensioner. Shawn has to be using a tension meter to lock his belts in like this.

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NachoMahma (author)Franx2007-11-01

. I'll guess that positioning the mass near the center of the belt will dampen the vibrations.

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NachoMahma (author)2007-10-18

. Does anyone know where I can find info on local wind speeds? Something similar to an insolation chart, but for wind. I'd like to know how often the wind is >5MPH around here.

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gizbiz (author)NachoMahma2008-10-05

If you have an Agricultural Extension Office around you, they should have that info.

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user

I might build one during winter break, it's similar to the aeolian harps I used to make, different purpose, similar structure.

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. Thanks! . Wouldn't ya know it? According to the chart, I live where the wind doesn't blow much - and I've had 3 tornadoes within 4 blocks of my house in the last 7-8 years. hmmmmm. Guess we don't get much wind otherwise.

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Goodhart (author)NachoMahma2007-11-28

You really need to eat more legumes I suspect. :-)

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gizbiz (author)2008-10-05

I read where someone wanted the url for Mylar Taffeta. Here it is:http://ecom.citystar.com/hang-em-high/ushop/index.cgi?ID=FZPHD4&task=show&cat=FABRIC&pgidx=23
I think you better cut and paste this for it to work.
I've been reading, and studying this issue since I found about it, so please let me know what you learn. I am completely ignorant about how to determine values for any of the generating or transfer equipment.
I feel kind of lost because I can build just about anything with plans, but this 'flutter wind' generator is busting my b***.
If you find out anything, anything at all, please let me know.
I could wait until it's posted at Shawn's site, but I really don't want to.
They only want $.50 and $.65 for a 1 yard roll of 2.5 or 3".

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Electron2 (author)2008-08-11
Ok......had to join just for this....not the sharpest guy in the drawer, but FAR from the dullest....very bad on typos...for those who have a problem with it, look like you'll miss out on lots of good stuf!<<Select as Best AnswerUndo Best Answer

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Kiteman (author)2008-05-07

You can get taffeta from art-and-craft shops, it's a decorative fabric.

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sfrayne (author)2007-10-17

hey, I'm the windbelt guy, Shawn, and I have to say, I'm sort of honored that this thread has started on Instructables. I don't want to contaminate your re-creation efforts with the specifics of what I did for those prototypes in the PM video, but I did want to point out a few hints: -The Windbelt, even the crude protos in the videos, can take airflow from a variety of attack angles and still pump out juice. Something like 60 degrees of variability works out surprisingly well (of course, power drops with the reduction in exposed cross-section of the vibrating belt). Also, unlike with most turbines, the Windbelt can take airflows that are either turbulent (e.g., from a ventilation fan, or around buildings) or laminar. -While on the topic of turbines, a nuance that I'm getting some heat for: In the PopMech article, I say that the Windbelt technology is 10X more efficient than micro-turbines. Micro! Not big turbines. You can crunch the numbers -- the most well-known micro-turbine work was published in Nature a few years ago...just do a search for 'wind-powered WiFi' and you'll find it. Also, you can find the refs on the "Windbelt" section of the Humdinger Wind website. So, that's the benchmark that we'd compared ourselves to there, just for clarification... -The windbelt embodiment in those videos can take airflows of between 4-14 mph without any adjustment, and the power output increases accordingly (not quite to the cube of the windspeed, but close). Above 14 mph, the reported-on protos sort of hiccup, and maintain a constant power output. Which is totally not good enough for a real, rural lighting app. So, I am working on expanding this "bandwidth" to about 4-24mph for larger belts, without resorting to a dynamic tensioning system (which of course is festering in my mind too, for really large installations) -You can use a whole lot of different materials for the belt and get some output, but it's easy to get a few orders of magnitude less output than you can with better materials -- I've used Mylar-coated tafetta, after trying a few dozen other materials, and that works pretty well -- super thin polyester tape (used to repair film reels) works OK, but is loud (but is available from McMaster, so a plus) -- also, the dimensioning of the belt and its balancing is key. Super key. But I'll be curious to hear about what you all discover... -The protos shown in the video run at around 90-100hz in 10mph wind. The AC output before conditioning is pretty much a perfect sine wave, as you might expect. -You have to balance your system so that the magnets oscillate up-and-down, without much torsion. The magnets should feel like they will break your fingernail when they're moving (um, slight exaggeration, but when you get it, you'll know what I mean). This is a much, much more substantial mode than a simple torsional mode. This is the wizard behind the curtain. -That coil setup shown is not the most efficient, at all. But it works at low windspeeds. Other configurations are much more efficient at higher speeds. -After experimenting with several generations of the small, 45.5 cm long windbelts, I've figured out how to reliably make them run quietly. Really quiet, like a leaf in the breeze quiet. So it's possible on those scale for sure....on the larger scales, well, let's say that's a work in progress. I'm super excited to see if some folks in the Instructables community can recreate my results (or better) without any more clues than that. I'm treating this like an experiment for how ideas spread, but if that annoys you, of course shoot me an email and I will give you more details if I can. I will say that I am preparing a formal tech brief/Instructable, for a slightly larger Windbelt -- I'm working to make it failure-proof in random reproduction, which the current design certainly is not, so I'm telling folks I'll have it posted on my website and/or here by mid-January. Thanks again for the interest, really -- and like I said, feel free to email me with questions -- I am under a flood of emails now, but I'll get to them all. Email's on my site. -Shawn

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killerjackalope (author)sfrayne2008-04-30

how about using a near perfect balance arm attached to the belt itself with the magnet on a rod on one end, it seems like it would be an odd way to go about things but when you think about the fact that a hammer shaped end with cylinder magnets either end could be almost constantly surrounded by a coild and generating current more of the time, this wouldn't be practical on tiny items but would work on larger scale windbelts, though I'm not sure iff it would be efficient or not, oddly enough I've been experimenting with linear production of power rather than rotational though my idea was about wasting less energy in small combustion engines running generators, the engines convert to rotational movements instead of reciprocal and as an example a rotary engine is far more efficient by starting with rotational, my idea is to saty reciprocal and avoid losses with more fuel efficient piston engines, ideally a two stroke single cylinder operating at high rpms is probably ideal, however that depends on tech, the idea works with steam engines or any other engine that uses pistons, steam engines may be a good route to go down, using multiple expansions and technically more than one generator, sorry been rambling for some time now...

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Actually my ramble just gave me a big idea, see steam turbines are pretty efficient but multiple expansion cylinder engines can do much the same in terms of efficiacy as they have such low energy losses, piston to piston, I may have to explore this, anyone hazard a guess how hard a steam piston is to build, double acting not necessary, I think...

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Can the 'ribbon' contain hundreds/thousands of parrallel wires and thus become the coil? The magnet could be moved to the centre of the 'ribbon' where the larger oscilations are. Now the wires are moving through the magnetic field (versus trying to move the heavy magnet).

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That sounds like a great idea for larger scale ones... you can put wires through a thin tap no problem, durability would be a difficult bit but on large scale windbelts the wires could be great for helping make a good tension based 'belt'... The only problem is that the magnets would be at either enf of the travel or beside it, with a long cylinder shaped coild at the ends you can get a near constant alternating current generation, as in it makes power all the time, if the magnet was in the middle of the belt somehow then you could have full advantage of the larger oscillations...

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static (author)sfrayne2008-02-11

Shawn- great that you mix with we amateurs, thank you. I have to say I'm surprised to learn that the AC wave form is any where close to sinusoidal. Not an issue at the micro power generation level, but may be on the larger projects you in visioned during your tech talk at Google. There seem to be a lot of people who can't understand how even micro electrical power generation can better the lives of people that have no electrical power what so ever. One can hope they don't stand in your way in improving the lives of others.

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gmoon (author)sfrayne2007-10-18

Shawn--

Thanks for the comments. I hope you're getting input from more than the instrucables community (edu, gov, foundations, etc.) It's a great concept, and you have certainly not taken the profit route (I hope you've got a supportive employer ...)

Operational at 4-14 MPH is pretty amazing, especially for a prototype (and still functioning at higher speeds.)

Hopefully, engineer and hobbyists all over are tinkering away as I write this...

Also, you ref your website, but don't include a link. Add that to this thread, please...

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NachoMahma (author)sfrayne2007-10-18

. Any idea when the Developer Kits will be available and approximate cost?

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sfrayne (author)Kiteman2007-10-22

Regarding the Developer Kits: I am working on a slightly larger scale Windbelt that people can put together themselves, and I expect to put out a tech brief about this in mid-January on the Humdinger Wind website. If all goes well there, a Developer Kit should follow in mid-2008. But I know the people on Instructables will be able to make a functioning Windbelt way before then. I should note that there are patents pending on the foundational Windbelt technology, since part of our strategy is to license the IP in wealthy countries, and use part of those funds to develop the product further in Haiti and other developing countries. That caveat aside, it is completely cool to make a couple Windbelts on your own for your personal educational/experimental use, and you can make/sell/do whatever you want with this technology in almost all developing countries (of course I haven't sought any patent protection there, so the technology is in effect open source in developing countries). If you've any questions about this, please don't hesitate to shoot me an email...! -Shawn

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gmoon (author)sfrayne2007-10-22

Thanks, Shawn, for the info and for encouraging the community! I hope this technology has a substantial positive impact (it certainly has great potential.) And here's hoping you do well developing it, also.

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Goodhart (author)sfrayne2007-11-28

Would this work in conjunction with the Wind Dam project listed in the forums elsewhere ? Just a thought....

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gyromild (author)sfrayne2007-10-18

It's great that you're sharing all these info with us. Greatly appreciated! Just curious, is there any particular reason that the coils are placed on only one end of the belt instead of both? And also will placing the coils + magnet closer to the center of the belt (where it flutters at larger amplitude) increase or decrease output? This idea certainly opens up new possibilities. Thanks again for sharing.

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deanis15 (author)2008-04-30

I am trying to build the wind belt device for a project at school but i have a few issues i cant get over before i start. I am trying to maximize the induced current in the coil. Hopefully doing so will give me a guideline as to the tension, width, amplitude, and desired frequency. Though i realize that the device may have to work at different wind speeds. Given that the coil is fixed and its area is constant the change in magnetic flux is proportional to the change in magnetic field. eg. Mag flux Phi=BAcos(theta), Emf (V)= -N(the number of coils in the solenoid) x d(phi)/dt. If i am trying to maximize power P=I2R, since power is related to the current, and Emf is related to the current as well b/c Emf is voltage, V=IR. SO maximizing the current and/or voltage should get me the most power output i.e. My ultimate goal. I know my magnets strength is about 7 micro Teslas. If i can figure out a way to maximize the change is magnetic field i.e. the second derivative of magnetic flux (i am assuming in this case that the second derivative of the magnetic field [interjection= i dont know if that's possible?] is porportional to the change in Emf and/or the second derivative of the magnetic flux.) Then i can find a maximum change in magnetic field, which hopefully will allow to me to relate magnetic field to the Amplitude, frequency, and period needed to create such a change in magnetic field.

I dont know if this is possible to do mathematically. And i have one major question which is if I passed the magnet through the coil with a cycle period of lets say .001 seconds, supposing the magnetic field still passes through all the wire loops of the solenoid would that guarantee me a greater Emf produced (which in turn i think would mean greater power produced) than a magnet of the same field strength with a cycle period of .01 seconds.

Basically, in order to produce the most power am I just trying to make this thing vibrate as fast as possible. And if so does anyone know of some way to relate all the variables b/c at the moment im strugglin to do so.

Thanks

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isurge (author)2007-11-06

I built one and it works ... a little box made of 1x4's 24 inches on a side then cut 2 cm deep notches every 2 cms on two of the sides to slide the mylar strips through(varying sizes) I made some little wooden wedges to lock the mylar and coils in place .... I am using two niobium 8mm x 3mm disk magnets one on each side of the mylar with just one coil at the moment .... if I can find my usb card reader I'll put pics and video up .. I went by radio shack yesterday and bought a bridge rectifier .. see if i can trickle charge a battery --- anyhow back to coding

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akimbo m (author)isurge2007-11-06

Can you try putting the coil on the mylar strip instead? With the magnet on either side of the coil. I am thinking that it would be lighter that way, thus allowing more vibration. It might increase it's efficiency.

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user

I've given some thought to that, I think he did it the other way as wire is cheaper than magnets, but I'd try the other way also. Then you could use unreasonably strong magnets.

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static (author)Tool Using Animal2008-02-11

"unreasonably strong magnets" may be a factor in this design or any other design for that matter You could find a point that the energy from the belt is strong enough to create the motion.

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