Hackaday Prize 2022: A 3D Printed Portable Wind Turbine For Hikers

A boy looking at a small wind turbine

If you’re out in the wilderness and off the grid, but still need to charge your phone, the most obvious way to do that is by using a solar panel. Light, flat and without moving parts, they’re easy to store and carry on a hike. But they obviously don’t work in the dark, so what’s a hiker to do if they want to charge their devices at night? If you happen to be in a windy place, then [adriancubas] has the solution for you: a portable wind turbine that folds up to the size of a 2 L soda bottle.

[adrian] designed the turbine to be light and compact enough to take with him on multi-day camping trips. Nearly all parts are 3D printed in PLA, and although ABS or PETG would have been stronger, the current design seems to hold up well in a moderate breeze. The generator core is made from a stepper motor with a bridge rectifier and a capacitor to create a DC output. [adrian] estimates the maximum power output to be around 12 W, which should be more than enough to charge a few beefy power banks overnight.

All parts are available as STL files on [adrian]’s project page, so if you’re looking for some wind power to charge your gadgets on your next camping trip you can go ahead and build one yourself. While we’ve seen large 3D printed wind turbines before, and portable ones for hikers, [adrian]’s clever folding design is a neat step up towards making wind power almost as easy to use as solar power.

44 thoughts on “Hackaday Prize 2022: A 3D Printed Portable Wind Turbine For Hikers

  1. That’s going to have to get smaller to get in with the ultralight and long-haul crowds. Ditch the pole and mount to a trekking pole (guy wire with tent stakes), with a lower caddy that rotates in tandem with the turbine to hold a battery pack or phone being charged (so the cord can’t get wrapped around the support pole, or worse pulled into the blades).

    All that said, this is a good start.

    1. Since it looks like he’s already carrying the tripod for photography, this is all he’d need.

      There are a lot of options for solving the wire problem.
      * Mounting the storage cells on the rotational vane seems easy, but would add a lot of mass that would have to be frequently overcome to rotate face into the wind, possibly eating into efficiency.
      * Stick a magsafe-type disconnect in there in case the wire gets wrapped around the pole so it doesn’t rip the wires out.
      * Slip rings.
      * Keep the wire, but add rotation limiting stops at about 180-270 degrees. That would usually be enough to face into the prevailing winds (if the winds are any wilder than that this whole thing would probably blow down anyway.)
      * Don’t worry about it until it proves to be a problem.

      1. The fact he’s carrying a full sized tripod for photography, is all the proof I need that he has never actually backpacked in his life. Mount it to the handle of your entrenchment tool and take it down when pooping. No single use things in pack.

        The fact that his blades aren’t twisted at all, is all the proof I need that he has never actually looked at a working propeller or windmill. Nor given the matter much thought.

        The fact that he’s using a stepper motor as a generator, is all the proof I need that he never done a project with any motor more complicated than a stepper. Did he even test it with a load? A generator without a load resistor becomes a tachometer, measures rotation speed, not power output. Results will always say ‘smaller prop, lower pitch, better’.

        Also lose the weather vane part and turn it around. Wasted weight. Granting once you decide you need a photographic tripod saying ‘F the weight’ is understandable.

        Hackaday should have a kids section. For projects we shouldn’t be critical of. Kids making an effort should be encouraged.

        1. The blades seem to have a perfectly reasonable profile, balance of easy to pack and make vs optimal aerodynamics.

          No reason to loose the weather vane part either – choice of better effort free output vs having to manually sort it out all the time – if you go off and make camp for a few days you’d like it to work whenever there is enough wind for all of those days, and be able to deal with changing gusty conditions.

          As for the stepper – why not, if its the motor you have/ can get easily why not use it. Sure you can dive deep into better windings, magnets, the very valid debate on if brushed would be better for this, materials to lower the weight, but at some point if you want to actually make something you have to use what you can get.

          Also I’d not moan about carrying a full size tripod as never having backpacked – a good tripod is light, durable, and really easy to strap to the side of a backpack. Seriously its taking the camera which poses more trouble – it and the lens are either a lower end model so really rather delicate, needing a great deal of protection from the elements or stupendously expensive pro stuff, so you treat it like it needs a great deal of protection (though it actually at least on paper doesn’t care about getting rained on etc), as trying to find the money to repair/replace it would suck…

          You could argue Native American or Aussie Aborigine stye that taking anything but the basic tools like your knife is too much – carry the knowledge and you don’t need to take a tent, food, lots of water etc… Who needs a backpack?!?! Or you can take the Victorian* Explorer (or Top Gear) approach, take everything you might possibly need in a massive convoy so you can be comfortable and not need to understand the local landscape at all (didn’t work out well for the Victorians sometimes though – for instance dead most likely of poisoning from the early canned goods…).

          *(Well Victorianish really – any time after the industrial revolution has started motoring, but the world isn’t even close to properly explored)

          1. The blades are ALL wrong, way too much wrong with them to even start. Hint. What works at one radius doesn’t work at all of them. You could make them half the weight and make more power for a given wind. Also 3 blades is 2 too many for compactness. An argument can be made for 2, so the balance weight is also generating, not just hanging there. 3? Why?

            You put the blades downwind so it can track without a vane.

            Steppers suck as generators. Suck! My point was he likely only had steppers on hand and likely had the thing setup to generate 0 power (no load, except a 10 M Ohm meter).

            Have you ever carried a backpack for days?
            I remember the first time I did, I brought along single purpose junk like a full size tripod too. Hell I had a 35mm camera, 3 lenses, a set of binoculars AND beer (not liquor, beer).

            Even today, I’m not hardcore. I shave ounces, spendthrift backpackers shave grams.

            I might just put a camera mounting screw into the end of my entrenchment tool. Monopod, needed for burying poop and digging of shallow graves. I’ve said too much.

          2. Yes I’ve carried stupidly heavy backpacks, sometimes for ages, but as though school my backpack was always 10Kg often 15Kg (and this was long before I hit fully grown) and heavier its never much bothered me – just get a backpack that spreads the weight decently (add in the waist strap if going really heavy) and you can cart around a very large fraction of your body weight without it being too onerous. What really kills you is lots of weight all hanging off thin straps on the shoulder – heck one camping trip with my school mates I ended up carrying most of two packs as one of the girls twisted her ankle, that actually felt like hard work being more poorly distributed extra weight, but because my own pack fitted well I could manage the extra…

            Yes I know blades with a twist will work better, but they are harder to make (and may well be much harder to pack/store – it changes their effective volume occupied quite significantly. As for making them lighter, perhaps a little but not all that much as to take a sufficient range of wind load your twisted blade would still need to be rather thick to be stiff enough.

            3 blades also makes sense as its something you can balance to take side load off the bearing and have more blade area to catch those light breeze – it will function very well where there isn’t enough breeze to drive that single blade of similar length around.

            A single blade is almost impossible, the structure you would need to take the off balance wind loads at this scale no doubt vastly dwarfs the weight of an extra blade or two… There is a reason all the big wind turbines, most high performance warplanes of the prop era etc are 3 blades or more!

            I’ve got no objections to multipurpose, if your entrenchment tool is built so you can add a thread into it without making it useless at its primary job that is great. But a mono pod is not a tripod, there are times it won’t be suitable for the photography you intend to do – you can’t assume that just because you would find a short stumpy monopod on the spade handle sufficient everyone will.

            Also there is nothing wrong with steppers as a generator (at least some of them) might not be the best choice here but the type of stepper that works as a generator works pretty well. However on this scale I think I’d use a brushed gearbox motor in reverse – very cheap, very light, gearbox means you can get a bit more usable voltage out of the generator, and if needs new brushes after a few trips its not a big deal.

            (Note I don’t go out of my way to make things heavier or harder than they need to be, but I’m not bothered by hauling extra weight within my capacity when there is a reason for it)

          3. Foldi:

            Most RC pylon and control line racers use single bladed props. It works fine. They do it mostly so the blade isn’t damaged on landing. You can (and should) make that single blade long and wide enough to hold the power and you need a counterweight.

            When your are backpacking (w a frame pack, belly band etc), you are heavy to begin with, just from survival gear. It’s nothing like carrying a backpack at school or on daytrips.

            Blades need twist if the radius changes significantly. Flat blades, like this one, will always been stalled over a significant part of their length. Sure you have to optimize for a design RPM and speed and won’t be optimized in all conditions, but a flat blade is never optimal. Twisted blades stack just fine.

            Thickness? You _want_ a thick airfoil for wind (it’s slow). But airfoils only matter if the blade isn’t stalled. Not being stalled can get you an order of magnitude more efficiency.
            Stiffness is unlikely to be an issue, considering this isn’t burning any nitromethane.

            Propellers (not in hover) and windmills are most efficient with fewer blades. Propellers (in hover) are most efficient with more blades.

            The main point is. Too big, too heavy, clearly not for backpacking.

          4. Pushing power down a single blade, revving it up to a few thousand RPM most likely is an entirely different thing to trying to extract energy from moving air with it!

            That single blade has only finite surface area to catch wind on, if you have enough wind to really get it up to high speeds it might work as well or better but at the lower end its going to be damn nearly if not entirely useless compared to the folding 2,3,4 bladed propeller – there is a reason why wind turbine, windmills, everything that has ever tried to extract power from the air uses sometimes a stupendously vast number of blades/sails – because it gives them enough working area to actually function in lower winds!

            And twisted blades may stack, but they don’t just folk flat against the hub creating such a tidy and ready to deploy package – if you end up having to take a toolkit to put it together you are carrying lots more wasted weight for assembly – this flat blade isn’t optimal, but its perfectly functional, easy to make and folds the whole unit down into a decently compact package. Its a perfectly valid compromise, and at the speeds its going to be rotating being mounted so low to the ground its not going to make a blind bit of different most of the time!

            The thickness comment was meant to tie into weight – thicker means heavier in nearly all cases.

            You can take however much you like when Backpacking HaHa, if its all in a backpack its still backpacking. Just because some folks can venture into the wilds with just a machete/axe/knife (delete or add to suit environment) and live comfortably because they really have the knowledge of bushcraft, and the practice to use that knowledge doesn’t make your carrying an actual backpack with however little you take incorrect, or somebody carrying a much heavier pack because they want something else out of their backpacking excursion incorrect either!

        2. Steppers are decent generators actually. Probably too heavy for a portable wind turbine though.

          Shaped blades only really matter once they are over a certain length. Doesn’t matter much for one this size.

          1. > Probably too heavy for a portable wind turbine though.

            Although I should note they are mechanically simpler than DC motors with gear boxes, since they can be driven at low RPM; reliability is a big win for portable uses

  2. Plain stepper motors are not permanently magnetized, although they retain a residual field from when they were last powered on. It’s possible that they become demagnetized over time and the voltage output starts to drop. This should happen faster the hotter the generator gets.

      1. They would also make for bad wind generators because hybrid stepper motors have some permanent holding torque. The cut-in speed becomes zero RPM, so when the blades stop in a wind gust, they won’t start again until greater wind speeds because the generator is not free to spin up.

    1. Rechargable batteries are not really an option if you go hiking for more then a few days.

      Wind energy does indeed have it’s own problems, but still I do like this Idea.

      I would probably make it a bit differently though.
      Some 30-odd years ago there ware some projects which used a cutout of a PVC pipe for the turbine blades.
      This project can be made lighter weight and compact by using a cutout of a soda bottle for each turbine blade. The hub would then just be 2 to 4 soda bottle caps.

      I would probably also ditch the whole wind vane and pivot system, it’s too bulky and heavy for backpacking. and if efficiency drops because of the non-optimal position, then there are probably still plenty of hours in the night to charge some batteries.

      1. Pretty much every thru hiker carries only a battery bank and usb wall charger, rarely a solar panel or other energy source. Its really not hard to carry more days worth of mAh than you can carry food in most situations. Any longer is more of an expedition, survival or off grid living and not just hiking.

    2. There’s definitely a breakeven point where it’s not worth carrying this vs a large lithium power bank, probably at about 3 days… depending on whether it’s just for keeping phone/GPS alive, or if heavy videoing or drone scouting is going on and you’re using 20,000mAH a day, then it’s kinda necessary to keep things going.

      1. While I agree there is one thing this or solar offers that a battery back can’t, and that is the ability to cope with a change of plans – the battery once it is empty isn’t ever filling itself up again.

        So really depends on where you plan to be and go as to if you should be factoring against the day or two you intended to spend out there, or the perhaps 2 weeks it could take to be ready to leave, get out or get rescued if nature throws you a curve ball.

        1. One thing to remember is that wind or solar generators are not reliable. If it’s not windy, no power. Overcast day, no power. You have to factor in a day or two of just waiting for power to become available.

          If you want “emergency power”, like charging up a phone to call for help, bring a TEC.

          1. Ultimately they are reliable enough, as you will get something out of them often enough, heck the wind turbine I guess could also be used as a hand crank generator if you are really desperate – TEC works too, at least if you can create the conditions for it to work, which isn’t exactly a certainty in an emergency either.

            I would say the most certain emergency power is the hand crank – get one of the squeeze in one hand ones and no matter what has happened to you it aught to be possible to find a way to make it work with some ingenuity. But really for emergency IMO you should have the second battery only to be used in emergency – 100% certain power to your communication device for many hours, maybe even days (depending on device), a generator or leisure battery you take with you is just good for letting you enjoy the benefits of electric, fly your drone etc.

          2. If you’re going camping, your first concern is probably going to be fire. If you have fire, you have heat for the TEC, and therefore power for your phones and gadgets, and it doesn’t take as much space or weight than doubling up on extra batteries.

          3. I agree Dude its a good generator choice, but not perhaps a good ’emergency’ choice – as if you go and break your arm or something it could be rather hard to actually light a fire, not to mention not safe to light one where you are anyway – your emergency supply should be usable with frostbitten fingers, one hand, real worse case type stuff to really count as emergency.

    3. may i ask, what would you recommend as a power source to recharge the rechargeable battery?

      carrying large enough of a battery for all needs on one recharge is not always feasible, so a recharge power source sometimes called for

      1. The ‘standard’ backpacker way is a small solar panel that clips to the top of your pack.

        Most people don’t bother. How much power do you need in the woods anyhow?

        1. A small solar panel dangling on your pack in a random direction also doesn’t generate much power at all. You have to stop and set it up to face the sun. Many devices just refuse to charge when there’s just some few milliamps available.

    4. totally different context…but we were kayaking around the hilo harbor and looking at all the sailboats and a lot of them had little propellers like this. i saw a person on one of the boats so i took the opportunity to ask her if it was useful, and she said that it was. she said it’s not much but it’s an amazing improvement over not having electricity between ports.

  3. Since when do you take a phone hiking anyway? You go hiking to get away from all that ‘stuff’. Most places it just wouldn’t work anyway,.. Traveling down the highway even has blank spots. A compass seems like a much better idea to take and of course the survival basics — none require electricity (well maybe a flashlight).

  4. It’s impossible to tell from the writeup and the video to understand the actual output from this rig.

    Assuming the displayed open-circuit voltage of 21V and short-circuit current of 0.75A implies a generator impedance of 28 ohms. Maximum power out will happen when feeding a load of the same impedance, so that’s 21V into 56 ohms, or 8 watts at that wind speed. 50% of the power in this case is lost in the generator.
    Generously assuming the prop efficiency of also 50% implies the wind power here was 32 watts.
    Guesstimating that as a 50 cm disc, that will be about a 20 km/h breeze — pretty near average for a 50-m high wind turbine in a mediocre location. 50 m is a bit longer than an average camera tripod though. Ground level wind in most places is going to be a lot less than that most of the time.

    The rig kind of tethers you to one location, and wind dies at night. So how many hours a day can you actually use this effectively? Can you really expect enough energy out of it to justify carrying it?

    Honestly, I’d budget what energy I need and carry it. 18650s carry 200 Wh/kg and are dirt cheap. Lithium AAs pack 350 Wh/kg. Lithium Thionyl D cells pack a whopping 688 Wh/kg, but it’s tough to justify their cost unless you’re packing for Mars (they were used on the Sojourner rover for operation through the night, and lasted 8 weeks, but retail at $1/Wh).

    The breakeven point from 18650s to generator+gasoline is around 3 kWh or 20 kg.

  5. I’ve been contemplating how to free-ish-ly and cleanly charge our phones, tablets and various devices by using a solar panel or small turbine to charge up a few power banks.
    And then, just today, before I saw this, I came upon a crowdfunding campaign for just this idea, (and while trying to find it again there are plenty similar small wind turbines already on the market)…. It has a built-in 12,000 mAh power bank and weighs 3 lbs, but it costs $325…
    This hack could definitely be improved upon.
    Blade design, using something better than a stepper motor, using it to change a power bank while you’re away from the campsite,
    (Or right outside the kitchen window) etc. I’ll be following. Here’s the link:

  6. I don’t like the word “stronger”. It’s like providing a number without units. It’s meaningless.

    Article says ABS is “stronger” than PLA, but PLA is stiffer/more rigid. That is a certain kind of strength, but not the only kind. ABS is indeed tougher, more ductile and elastic than PLA.

  7. The most obvious to me would be a jack coming out of my squeeze to charge flashlight going to the whatever. The last thing I would wanna bring would be a big thing I have to bolt together that has no other use but to charge batteries. But that is just me.

    1. The datasheet says 1.3kg.

      “12 Ah” in the modern parlance means 40 Wh, equal to four 18650 cells that weigh in at 200 grams. (Though they do claim “5V 12,000 mAh”, which I’m guessing is just wishful marketing speak.)

      How much energy do you need, and what do you want to pay for it in weight and cost?

      1.3 kg of wind charger can deliver “up to” 40 watts, if you can find the wind and want to spend the time to set up and hang around and wait for the joules to saunter in, and enjoy being in a strong breeze all the time.

      1300 grams of AA lithiums cells will give you almost a half kilowatt hour, for less than US$200. This will run even my power-hungry phone for about 3 months.

      1300 grams of AA alkalines will deliver 200 Wh, for less than US$30.

      1300 grams of 18650 lithiums will deliver 260 Wh for about US$100, and you can use them many times.

      Just for completeness, 1.3 kg of lithium thionyl cells will deliver 900 Wh, but will set you back a kilobuck.

      If you’re going to use this wind generator at a fixed camp or on a boat, OK, sounds great. But backpacking? Good luck.

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