Model Hydroelectric Plant Is An Illuminating Educational Tool

July 21, 2020 by Kristina Panos 6 Comments

There’s more than one way to light up a strip of LEDs. Have you tried building your own hydroelectric power plant to do it? Well, now you can. Replicating [Matic Markovič]’s entry into the 2020 Hackaday Prize is bound to teach you something, if not many things, about the way hydroelectric power is generated and the way the variables play into it.

In [Matic]’s model, water from an adjustable-height reservoir flows into a 3D-printed Pelton turbine. The water jet hits the turbine’s cupped fins at a 90° angle, causing the assembly to spin around rapidly. This mechanical energy charges a brushless DC motor that’s connected to an Arduino Nano, which rectifies the AC from the generator and uses it to light up an RGB strip like an equalizer display that represents the power being generated.

This is easily one of the coolest educational displays we’ve ever seen. The reservoir can move up and down over a 55 cm (21.6″) range with the flick of a three-way toggle, which makes it easy to see that the higher the reservoir, the more power is generated. [Matic] has the STLs and INOs in the usual places if you want to make your own. Flow past the break for a demonstration, followed by an exploded render that gets put back together by invisible hands.

Your hydroelectric setup doesn’t need to be fancy, it just needs to work. One man’s trash can be another man’s off-grid phone charger.

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Experimenting With Vibratory Wind Generators

June 30, 2020 by Tom Nardi 42 Comments

We’ve all got a pretty good mental image of the traditional wind-powered generator: essentially a big propeller on a stick. Some might also be familiar with vertical wind turbines, which can operate no matter which way the wind is blowing. In either case, they use some form of rotating structure to harness the wind’s energy.

But as demonstrated by [Robert Murray-Smith], it’s possible to generate electrical power from wind without any moving parts. With simple components, he shows how you can build a device capable of harnessing the wind with nothing more than vibrations. Alright, so we suppose that means the parts are technically moving, but you get the idea.

In the video after the break, [Robert] shows two different devices that operate under the same basic principle. For the first, he cuts the cone out of a standard speaker and glues a flat stick to the voice coil. As the stick moves back and forth in the wind, the coil inside of the magnet’s field and produces a measurable voltage. This proves the idea has merit and can be thrown together easily, but isn’t terribly elegant.

For the revised version, he glues a coil to a small piece of neoprene rubber, which in turn is glued to a slat taken from a Venetian blind. On the opposite side of the coil, he glues a magnet. When the blind slat starts vibrating in the wind, the oscillation of the magnet relative to the coil is enough to produce a current. It’s tiny, of course. But if you had hundreds or even thousands of these electric “blades of grass”, you could potentially build up quite a bit of energy.

If this all sounds a bit too theoretical for your tastes, you can always 3D print yourself a more traditional wind turbine. We’ve even seen them in vertical form, if you want to get fancy.

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US Air Force Says They’re Developing An Open Source Jet Engine; We Say Show Us The Design

November 27, 2019 by Tom Nardi 46 Comments

The economies of scale generally dictate that anything produced in large enough numbers will eventually become cheap. But despite the fact that a few thousand of them are tearing across the sky above our heads at any given moment, turbine jet engines are still expensive to produce compared to other forms of propulsion. The United States Air Force Research Laboratory is hoping to change that by developing their own in-house, open source turbine engine that they believe could reduce costs by as much as 75%.

The Responsive Open Source Engine (ROSE) is designed to be cheap enough that it can be disposable, which has obvious military applications for the Air Force such as small jet-powered drones or even missiles. But even for the pacifists in the audience, it’s hard not to get excited about the idea of a low-cost open source turbine. Obviously an engine this small would have limited use to commercial aviation, but hackers and makers have always been obsessed with small jet engines, and getting one fired up and self-sustaining has traditionally been something of a badge of honor.

Since ROSE has been developed in-house by the Air Force, they have complete ownership of the engine’s intellectual property. This allows them to license the design to manufacturers for actual production rather than buying an existing engine from a single manufacturer and paying whatever their asking price is. The Air Force will be able to shop ROSE around to potential venders and get the best price for fabrication. Depending on how complex the engine is to manufacture, even smaller firms could get in on the action. The hope is that this competition will serve to not only improve the design, but also to keep costs down.

We know what you’re thinking. Where is the design, and what license is it released under? Unfortunately, that aspect of ROSE seems unclear. The engine is still in development so the Air Force isn’t ready to show off the design. But even when it’s complete, we’re fairly skeptical about who will actually have access to it. Open Source is in the name of the project and to live up to that the design needs to be available to the general public. From a purely tactical standpoint keeping the design of a cheap and reliable jet engine away from potential enemy states would seem to be a logical precaution, but is at cross purposes to what Open Source means. Don’t expect to be seeing it on GitHub anytime soon. Nuclear reactors are still fair game, though.

[Thanks to Polymath99 for the tip.]

5 Kilowatts In A 3D Printed Jet Boat

November 14, 2019 by Lewin Day 10 Comments

Radio control projects used to be made of materials such as metal or wood, and involve lots of hand crafted parts. That’s still one way to go about things, but 3D printing has become a popular tool in recent years. [RCLifeOn] has been working on a 3D printed jet boat, which recently got a serious power upgrade.

The boat in question received a 5000W brushless motor – significant power for a vehicle weighing less than 2kg. Powered by a 12S lithium pack, and outfitted with a water jacket for cooling, it drives the boat through an off-the-shelf turbine after initial attempts to DIY the drivetrain were unsuccessful.

The biggest problem in the project came from coupling the motor to the turbine. A 3D printed coupler was unable to hold up to the strain, while attempts to make a metal part failed due to the lack of a lathe. Eventually the solution was found by daisy chaining two off-the-shelf parts together.

The boat proved itself ably on the water, with the large motor proving more than capable of shifting the boat at a strong clip. It’s an excellent shakedown for the parts that will eventually find themselves in a powered surfboard build. We’ve seen [RCLifeOn]’s work before, too, like these stylish 3D printed sneakers. Video after the break.

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Spin Me Right Round, Baby: Generator Building Experiments For Mere Mortals

August 13, 2019 by Brian McEvoy 38 Comments

How many of you plan to build a wind-powered generator in the next year? Okay, both of you can put your hands down. Even if you don’t want to wind your coils manually, learning about the principles in an electric generator might spark your interest. There is a lot of math to engineering a commercial model, but if we approach a simple version by looking at the components one at a time, it’s much easier to understand.

For this adventure, [K&J Magnetics] start by dissect a commercial generator. They picked a simple version that might serve a campsite well, so there is no transmission or blade angle apparatus to complicate things. It’s the parts you’d expect, a rotor and a stator, one with permanent magnets and the other with coils of wire.

The fun of this project is copying the components found in the commercial hardware and varying the windings and coil count to see how it affects performance. If you have ever wound magnet wire around a nail to make an electromagnet, you know it is tedious work so check out their 3D printed coil holder with an embedded magnet to trigger a winding count and a socket to fit on a sewing machine bobbin winder. If you are going to make a bunch of coils, this is going to save headaches and wrist tendons.

They use an iterative process to demonstrate the effect of multiple coils on a generator. The first test run uses just three coils but doesn’t generate much power at all, even when spun by an electric drill. Six windings do better, but a dozen finally does the trick, even when turning the generator by hand. We don’t know about their use of cheap silicone diodes though, that seems like unintentional hobbling, but we digress.

Making turbine blades doesn’t have to be a sore chore either, and PVC may be the ticket there, you may also consider the vertical axis wind turbine which is safer at patio level. Now, you folks building generators, remember to tip us off!

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Vacuum-Powered Rotary Tool Redux, This Time Machined

February 28, 2019 by Dan Maloney 18 Comments

We love to see projects revisited, especially when new materials or methods make it worth giving the first design another go around. This twin-turbine vacuum-powered Dremel tool is a perfect example of what better tools can do for a build.

You may recall [JohnnyQ90]’s first attempt at a vacuum powered rotary tool. That incarnation, very similar in design to the current work, was entirely 3D-printed, and caused no little controversy in the comments about the wisdom of spinning anything made on an FDM printer at 43,000 RPM. Despite the naysaying, [Johnny] appears to have survived his own creation. But the turbo-tool did have its limitations, including somewhat anemic torque. This version, machined rather than printed and made almost completely from aluminum, seems to have solved that problem, perhaps thanks to the increased mass of the rotating parts. The twin rotors and the stator were milled with a 5-axis CNC machine, which has been a great addition to [JohnnyQ90]’s shop. The turbine shaft, looking like something from a miniature jet engine, was meticulously balanced using magnets mounted in the headstock and tailstock of a lathe. The video below shows the build and a few tests; we’re not big fans of the ergonomics of holding the tool on the end of that bulky hose, but it sure seems to work well. And that sound!

We first noticed [JohnnyQ90] when he machined aluminum from soda cans to make a mini Tesla turbine. His builds have come a long way since then, and we look forward to what he’ll come up with next.

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The “Impossible” Tech Behind SpaceX’s New Engine

February 13, 2019 by Tom Nardi 92 Comments

Followers of the Church of Elon will no doubt already be aware of SpaceX’s latest technical triumph: the test firing of the first full-scale Raptor engine. Of course, it was hardly a secret. As he often does, Elon has been “leaking” behind the scenes information, pictures, and even video of the event on his Twitter account. Combined with the relative transparency of SpaceX to begin with, this gives us an exceptionally clear look at how literal rocket science is performed at the Hawthorne, California based company.

This openness has been a key part of SpaceX’s popularity on the Internet (that, and the big rockets), but its been especially illuminating in regards to the Raptor. The technology behind this next generation engine, known as “full-flow staged combustion” has for decades been considered all but impossible by the traditional aerospace players. Despite extensive research into the technology by the Soviet Union and the United States, no engine utilizing this complex combustion system has even been flown. Yet, just six years after Elon announced SpaceX was designing the Raptor, they’ve completed their first flight-ready engine.

The full-flow staged combustion engine is often considered the “Holy Grail” of rocketry, as it promises to extract the most possible energy from its liquid propellants. In a field where every ounce is important, being able to squeeze even a few percent more thrust out of the vehicle is worth fighting for. Especially if, like SpaceX, you’re planning on putting these new full-flow engines into the world’s largest operational booster rocket and spacecraft.

But what makes full-flow staged combustion more efficient, and why has it been so difficult to build an engine that utilizes it? To understand that, we’ll need to first take a closer look at more traditional rocket engines, and the design paradigms which have defined them since the very beginning.

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