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A small Portable Wind Turbine, mostly 3D printed!

A wind turbine mostly 3D printed , which houses a Nema 17 stepper motor as an electric generator. Foldable and no larger than a 2L soda bottle. Simple to replicate and with a low manufacturing cost. CAD, STL and how to make it included.

Generally when I want to get away from the city and camp, I take some kind of power source with me. Within my preferences are the Power Banks. With a small and light one, of approximately 40 Watt hours (Wh), I can charge my cell phone about 2 or three times and that is fine if I am only going to spend a day and do not need to power other equipment such as my camera, for example. If I want to spend more time then I usually take a 222Wh “Solar Generator” with a 60W portable panel. For the energy needs that I have in this type of excursion, it is generally enough for me.
About a month ago I made an excursion of several days and to my surprise at the end of the second day my energy sources had been completely exhausted, also no Sun. I have discarded fuel generators because they are very noisy, polluting and can cause fires. There was a small stream near where I camped and there was also wind that I could have taken advantage of, but I really wasn’t prepared for it. I promised to find a solution and include it in my new adventures. I am sure that there are several people around the world with this type of need, that is why I carry out this project so that they can also benefit.
In this project I show you how to make a small portable wind turbine, mostly 3D printed, capable of providing about 12W of power and with dimensions similar to a 2L soda bottle when folded. Although its generation capacity is limited, having it can be beneficial during emergencies or when access to more convenient energy sources is zero or very limited.
Although the initial motivation to carry out this project was not linked to teaching at school, I consider that it constitutes an excellent opportunity to link this type of technology with the teaching-learning process. To be able to present a product of this type at School Science Fairs, which harnesses the energy of the wind wherever the conditions exist, small, very portable and easily installed, should be striking and interesting. Students could answer questions and present the results of electrical measurements of their performance at different wind speeds. I think it would be an enriching experience for everyone.

For some time the idea of designing a portable wind turbine had crossed my mind. From my experience and for it to be useful I knew it had to be small, maybe the size of a soda bottle, able to fit inside a backpack. Its mass should also be as low as possible.
Since the plane of rotation of the propellers in typical wind turbines is perpendicular to the position of the electric generator, they are initially inconvenient to transport and store once assembled, even when small. I also didn’t want to have to use tools to mount and dismount the propellers every time I was using it. Folding propellers, that was the idea, but how to implement it? It took me a while to come up with the answer. Have you seen the way bats sleep? The wings are folded towards the body, that could be the answer. Nature is an excellent source of inspiration, millions of years of evolution support it.
Taking the previous idea as inspiration, I designed this wind turbine.
Since on my travels I usually carry some kind of lightweight tripod to take pictures when the light conditions are low or to make time-lapses, perhaps also using it to support the wind turbine would save the need to carry other equipment. There are thousands of possibilities to support a camera and make it compatible with those pre-existing technologies, I think it would be convenient.
Regarding the generator to use, it was another difficult part to decide. Ideally it would have been to design and build a customed one, but unfortunately, I did not have the possibility of building a quality one as I did not have the required manufacturing technology at hand. That is why, a NEMA 17 stepper motor has been selected as generator due to its availability. Another reason to consider when selecting a stepper motor is that you don’t need to use multiplication gears to get a useful voltage and it doesn’t have brushes.
As creators we may have an amazing digital design, but it should be able to be built with the available resources. 3D printing! Thanks to it, we can now replicate this project as many times as we want. If a part gets damaged, we print it again and voila!
The typical dimensions of a 3D FDM printer are usually between 22 cm wide by 22 cm deep by 25 cm high. All pieces were included within these margins to maximize replicability.

In the following video I present the prototype number 1 of this project. Some improvements have happened since that video was filmed, such as the redesign of the tail for example. I have in mind other improvements derived from the field tests carried out on this prototype.
Another aspect pending development is the associated energy storage unit and a DC-DC converter with USB output for powering other compatible devices.”

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