Low-voltage Wind Turbine Lighting


Instructables user [Dustyn] recently constructed a wind-based lantern to provide a bit of free, renewable light in urban settings. The project is based around a vertical-axis wind turbine, which she says are better suited to these environments since wind often comes from all different directions. Despite their lower efficiency compared their horizontal-axis brethren, this style of turbine seems to fit her needs quite well.

She provided a complete bill of materials, down to the last screw and washer you would need to replicate her work. The wind sails were constructed from thin aluminum flashing, and inserted between two acrylic sheets. These were then mounted to the central aluminum shaft of the turbine, which drives the stepper motor built into the base.

The current from the stepper motor is rectified and run through a pair of capacitors before being used to light the attached LED. This allows the bipolar motor to provide current regardless of the direction the turbine is turning, and the caps smooth things out so that the LEDs don’t flicker wildly under varying wind conditions. The turbine is not going to light up a full city block, but it is definitely a nice alternative to sun jars.

Stick around to see a video of the turbine mechanism in action.

[flickr video=http://www.flickr.com/photos/dustynrobots/5539693723/ w=470]

30 thoughts on “Low-voltage Wind Turbine Lighting

  1. Nice project.

    Vertical axis turbines are NOT less efficient. Also efficiency is a useless term in renewable energy because there is no scarcity of energy.

    Vertical axis turbines are the future, because they do not have the instability inherent in turbines where the blade loses all pressure every time it moves in front of the support.

    Trivium: There is a rediculous 2010 US patent (12/720,377)that allows it’s owner to royalties for VAWT on top of buildings, pilons, traffic signs, cell towers.

  2. Why not a standard DC motor as a generator? There isn’t really a need for that and a rectifier since this design of VAWT only spins one way. Less cost, fewer diodes, and (I’d expect) higher efficiency! :D

  3. I think this would be allot more useful if it utilized some Cymbet ‘Enerchips’ instead of caps. But this is an awesome project highlighting ways to harvest energy.

  4. Efficiency is NOT a useless term in renewable energy. It tells you how much of the energy hitting your device you turn into useful work. Has nothing to do with how scarce the energy is.

  5. You may be able to get more power if you made it an impulse turbine. As is it catches the wind and trys to stop it, If you made it so the wind was getting scooped by the blade then you might be able to nearly double it’s efficiency. What you would do is make it to the hub of the turbine isn’t solid, rather the air getting scooped gets dumped into the blade opposide of it. This would work best with a 2-blade setup. What I’m talking about is take a circle, split it and half but instead of shifting a half by a distance equal to the diameter only shift it 2/3 of the diameter. Now imagine shooting a stream of water at one half, It will follow the half circle creating an impulse force, that spilled water would then run across the other blade creating a bit more impulse. the air would do the same thing. tricky part is mounting the scoops without a center hub to block the air.

  6. It’s beautiful, to be certain, and I’m not one to criticize art for art’s sake (I’m a photographer and a writer), but I do kind of wonder at the fascination with less-than-functional lighting.

    Crypto gives us the idea of “opportunistic encryption”; is this “opportunistic lighting”?

    “Better to fabricate a wind turbine than curse the darkness,” I suppose. I dunno; I like the dark, myself…

  7. “This allows the bipolar motor to provide current regardless of the direction the turbine is turning”

    Is this a typo or is someone not paying attention? This type of turbine only spins one direction.

  8. I’m not sure about the statement that HAWTs lose all pressure as the blade passes the tower. It causes some torque variation, but not total loss from that blade. It used to be a problem when many were blade-behind-tower configuration, but practically all commercial units are now blade before tower.

    Efficiency is not a useless term, it measures how well one system works in relation to another in the same situation.

  9. Looks nice, but in my part of the country it doesn’t usually get too windy indoors.

    Efficiency is very important. If you were building a wind farm, would you rather have twenty-five turbines that are 1% efficient, or one that is 25% efficient?

  10. Am I the only one who thinks this should be called;
    Lets take a simple project and make it really expensive. Nice idea, but scrap wood and junk parts would achieve the same results. I will say it did inspire me somewhat to replicate it with I have on hand if I had a use for it.

  11. @knox I think your project should be called:
    “let’s take a beautiful project and make it out of ugly junk because we don’t care about aesthetics”

    Make your prototypes look like crap all you want, but if you’re trying to make something that anyone else will want, you can’t use “scrap wood and junk parts”.

  12. When I was in Japan, they had many posts which had the the lamp, then vertical wind turbine and then a flat solar panel on top. So they can’t be that inefficient if Japan are putting these things all over Tokyo.

  13. @Devin: DC motors are less efficient than AC motors, due to losses in the commutator. and the brushes wear out.

    you mean like a Savonius turbine?

    You definitely will not double the efficiency. Thes are drag type turbines to start with, which prefer reliability over efficiency. Looking at the design, any crossover of blades will actually reduce the efficiency, not increase it.
    Unlike a transverse flow water turbine, which can add up to 50%, but certainly not double.
    Don’t forget, the blades are moving, not standing still. You throw water at it, and it will move out of the way, not stand still and redirect the flow for you.

  14. There seems to be a prevailing attitude these days that anything powered by some form of renewable energy is an unconditionally worthwhile thing to make, whether it is of any practical use or not.

    I beg to differ.

    It’s a nice project, and possibly looks great in places that are fairly windy at nigth – but I wouldn’t call it “lighting”, let alone usable lighting.

    Oh, and if you’re at least half-serious about this sort of thing, you really can’t afford to throw away half a day’s worth of energy by not storing daytime charge in a battery, I’d say… I do have to admit this does have the upper hand on the solar versions – you can scavenge a small electric motor practically everywhere these days, whereas a solar cell – not so much.

  15. No battery and associated negatives? Win. I’m coastal so wind is often available. Should be great for pool / yard lights.

    Increase the aesthetic factor and it could be a front yard lamp post as well.

  16. @Jean-Paul
    You are right about the brushes and the commutators, but I have to nit-pick that a stepper motor is NOT an AC motor. It is a DC motor with varying voltage. A true AC motor uses induced current for the rotor instead of permanent magnets.

    @Mike Nathan, all
    As pointed out, it only spins one direction, but that wouldn’t matter anyway. Any DC motor that spins will produce sinusoidal waveforms regardless of direction. A brushed motor will produce a single sine wave, whereas a brushless DC or stepper would produce multiple sinusoids out of phase depending on how it was wired. For best efficiency use a brushless DC as they are meant for fast, long term rotation whereas steppers are much more targeted to precise speed and position control.

  17. A better choice of generator motor and that thing could store power in a set of AA’s during the day and let out the light at 10X the brightness of that art project at night.

    Nice art project. IT’s a good early alpha version 0.01 that needs to be refined better by the community to become way better.

  18. I think it is a cool project, and a fun one as well. Everyone here seems to think it needs to be perfect… Its just a small VAWT project for fun lighting. I bet most of the folks that comment couldn’t build one of these on there own like this without instructions.
    Thanks for sharing, kudos to Dustyn, and I wonder if she has ever thought about making a bigger one with a similar design. Time to check out her site/blog.

  19. @Will-
    Your corrections require corrections… or at least clarification.

    Traditionally, stepper motors are not driven with “varying voltages.” To drive a stepper, you sequence the coils on and off. There are more elaborate controllers now that make use of PWM, bipolar currents, and and overlapping coil phasing to improve resolution and performance, but at the heart of things, steppers are on-off devices.

    As to your comment about “AC Motors,” I suspect that you are being sloppy with terminology. The motor you are describing is an induction motor. While all induction motors are AC motors, not all AC motors are induction motors. A universal motor, for example, will run on either AC or DC. Shaft direction has to do with the phase relationship between field and rotor coils.
    Induction in that case has nothing to do with it’s operation.

    A DC motor with a commutator and brushes does not produce sinusoids if you spin the shaft. In fact, the commutator to an extent, acts as an electromechanical rectifier.

    A motor with a permanent magnet field and slip rings (not a commutator) however, will produce a sinusoidal output.

  20. “Vertical axis turbines are NOT less efficient. Also efficiency is a useless term in renewable energy because there is no scarcity of energy.”

    Yes they are, at least this type is.

    The reason being that it slows the wind down too much at higher wind speeds. It tries to rotate faster and faster with the wind, but it can’t.

    When the wind picks up, its output will not increase like with other designs. Eventually the side load will be enough to stop it completely.

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