Go Fly A Kite

Harvesting energy from the wind has been a commercially viable way of generating clean energy for around three decades now. Wind turbines are a reliable, proven technology but they do have some downsides, one of which is that since there’s more wind higher above the ground this usually means tall, expensive towers. There is a way around this problem, though, which is using kites to generate energy instead of a fixed turbine.

While kite generators aren’t a new idea, [Benjamin] has been working on this kite generator which has a number of improvements over existing kite generators. Like other kite generators, this one uses a tether to spin a generator which is located on the ground. But while this is similar to other kite systems, this prototype has a much simpler design and sweeps a much larger area while in flight. It also has an autopilot with multiple independent steering systems, which [Benjamin] says will allow it to stay in flight for months at a time provided there is enough wind. If there isn’t, it can land reliably, and launching it is relatively fast and simple as well.

While kites do have some obvious downsides compared to fixed turbines including a single point of failure at the tether and a large amount of cleared area to operate, they have plenty of advantages as well. They’re smaller, simpler, require no complicated yaw system, and can be easily maintained on the ground. In fact, it’s possible to build very simple kite generators out of nothing more than a hobby kite and some readily-available electrical components.

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Printed Axial Generator Is Turned By Hand

While desktop 3D printing is an incredible technology, it’s got some pretty clear limitations. Plastic parts can be produced quickly in a 3D printer but can be more expensive or take longer to make than parts from materials like wood. Plastic parts can also be weaker than materials like metal. If a 3D printer is all you have on hand, though, you can often make some design choices that improve the performance of a plastic part over other materials. That’s what [1970sWizard] did to make this axial hand-cranked generator.

Besides a few pieces of off-the-shelf hardware and the wire and magnets, the entire generator is printed. The actual generator is made from coils of wire with exposed leads which snap into a plastic disc which acts as the generator’s stator. The magnets also snap into a separate disc which is the rotor of the generator and is attached to the drivetrain, with no glue or fasteners required. A series of gears on two other axes convert the torque from the hand crank into the high speed necessary to get usable electricity out of the generator.

The separate gear shafts were necessary to keep from needing a drillpress, which would have allowed fewer axes to be used. This entire machine can be built almost entirely with a desktop 3D printer, though, which was one of the design goals. While it’s largely a proof-of-concept, the machine does generate about 100 mW of power which is enough to slowly charge USB devices, power lights, or provide other sources of very small amounts of energy. If you do have access to some metalworking tools, though, take a look at this hand-cranked emergency generator.

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Hackaday Prize 2022: Treadmill Becomes Human-Powered Generator

Running on a treadmill is a great way to workout, but what if the effort you put in could be put to use? This treadmill generator from [Amitabh Shrivastava] does just that.

The build starts with a regular old treadmill, which has a motor inside typically used to power the tread. Instead, the motor’s control electronics were removed, and it was repurposed to work as a generator. The output from the treadmill’s DC motor was fed directly to a DC-DC converter. This was then fed to an inverter that generates 120 V AC, which can power appliances that use up to 20-25W based on [tinkrmind’s] running performance.

It’s a fun way to generate power during a workout. If you don’t want your treadmill’s monitor to die in the middle of a¬†Friends¬†rerun, you’ll have to dig deep on those long runs. We’ve seen similar builds before too, with exercise bikes being a popular method of generating electricity. In fact, that’s [Amitabh]’s next project! Video after the break.

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Gym Equipment Converted To Generator

Energy cannot be created or destroyed, but the most likely eventual conclusion of changing it from one form or another will be relatively useless heat. For those that workout with certain gym equipment, the change from chemical energy to heat is direct and completely wasted for anything other than keeping in shape. [Oliver] wanted to add a step in the middle to recover some of this energy, though, and built some gym equipment with a built-in generator.

Right now he has started with the obvious exercise bike stand, which lends itself to being converted to a generator quite easily. It already had a fairly rudimentary motor-like apparatus in it in order to provide mechanical resistance, so at first glance it seems like simply adding some wires in the right spots would net some energy output. This didn’t turn out to be quite so easy, but after a couple of attempts [Oliver] was able to get a trickle of energy out to charge a phone, and with some more in-depth tinkering on the motor he finally was able to get a more usable amount of energy to even charge a laptop.

He estimates around 30 watts of power can be produced with this setup, which is not bad for a motor that was never designed for anything other than mechanical resistance. We look forward to seeing some other equipment converted to produce energy too, like a rowing machine or treadmill. Or, maybe take a different route and tie the exercise equipment into the Internet connection instead.

the full charger with gas tank and engine

Charge Your Apple With Apples

When you think of ethanol, you might think of it as a type of alcohol, not alcohol itself. However, in reality, it is the primary ingredient in adult beverages. Which means humans have gotten quite good at making it, as we’ve been doing for a long time. With this in mind, [Sam Barker] decided to make ethanol out of apples to power a small engine to charge his phone.

The steps for making pure ethanol is quite similar to making alcoholic cider. A friend of [Sam’s] had an orchard and a surplus of apples, so [Sam] boiled them down and stored the mush in jugs. He added activated dry yeast to start the fermentation process. A dry lock allowed the CO2 gas that was being created to escape. Over a few weeks, the yeast converted all the sugar into ethanol and gas. In the meantime, [Sam] sourced a chainsaw and adapted the engine to run on ethanol, as ethanol needs to run richer than gasoline. The video below the break tells the story.

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Pedal Powered Power

When you have a solar-powered web server, where do you go next for a source of power? Instead of lazily mooching off the sun, you can use your muscle with a bike generator. [Ed note: The site is run on an entirely solar-powered server, so if it’s the middle of the night, you might have a better web experience here.]

We’ve covered bicycle generators before, so what’s new? For starters, the accessibility of chargers and batteries has changed significantly. Rather than just charging a phone or putting out a measly 5V, this bike can be integrated into an existing solar PV system and output many voltages. This guide goes over building one with hand tools with great detail.

It starts with a 1950’s vintage exercise bicycle, no hacksaw required. A friction drive connects a generator and makes for an incredibly compact generator/exercise machine. Calculating the correct gear ratio is crucial to getting the 12 volts out at an average pedaling speed. You want your range of voltages to be between 5 and 24 volts. With the help of a control panel provides 5v, 12v, 14.4v, and 220v to power a variety of devices. Boost and buck converters output these voltages (depending on whether the voltage needs to be set for a maximum or a minimum). A potentiometer allows you to dial back the power draw of certain appliances (an electric kettle, for instance), making a workout a tad easier on the human component of the generator.

Another key takeaway from this guide is using a wind charge controller to charge batteries. A solar charge controller will just cut the circuit when the batteries are full. A wind charge controller will increase the load until the motor breaks. Some controllers are also hybrid wind and solar, allowing you to connect a small panel like the one running the webserver this guide is posted on and then charge up the batteries when it has been overcast for a few days in a row.

Hub-powered bike computer

Battery-less Bike Computer Gets Power And Data From The Wheels

Bicycle generator technology has advanced far beyond the bottle dynamos of years past, which as often as not would introduce enough drag when engaged to stall the bike. Granted, it’s not as much of a current draw as a big old incandescent headlight, but this wheel-powered cyclocomputer is a great example of harvesting both power and data from the rotation of a bike’s wheel.

While there are plenty of cyclocomputers available commercially, [Lukas] was looking for some specific features. His main goal was something usable at night, which means a backlit display, ruling out the usually coin-cell power sources. His bike’s hub dynamo offered interesting possibilities — not only does it provide AC power, but its output frequency is proportional to the bike’s speed. This allows him to derive speed, distance, RPM, time-in-motion, and other parameters to display on the 1×8 character LCD display. There’s some clever circuitry needed to condition the output of the hub dynamo, and a 1.5 farad supercapacitor keeps the unit powered for about four days when the bike isn’t in motion.

As for measuring the frequency of the dynamo’s output, [Lukas] simply used a digital input on the MSP430 microcontroller, with a little signal conditioning of course. He also added a barometer chip for altitude data, plus an ambient light sensor to control the LCD backlight. Everything lives in a clever 3D-printed case with a minimalist but thoughtful design that docks and undocks from the bike easily; [Lukas] assures us that a waterproof version of the case is in the works.

We really appreciate the elegance of this design, and the way it uses the data that’s embedded in the power supply. While [Lukas] appears to have used a commercially available generator, we’ve seen other examples of home-brew hub dynamos before — even one that offers regenerative braking.