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.

Acordeonador, an 555 accordion powered by a CD player based genrator

CD Player Powered 555 Piano Goes Accordion To Plan

Ah yes, the 555 piano project. Be it the Atari Punk Console, or some other 555 based synthesizer, Hackers just love to hear what the 555 can do when attached to a few passives and a speaker. It’s a sound to behold. But for [Berna], that wasn’t quite enough! Below the break, you can see his creation, called the Acordeonador.

A portmanteau of the Spanish words for “Accordion” and Generator”, the Acordeonador does what no project we’ve seen so far can do: It turns a CD drive into a generator for a 555 based synthesizer.

To give the Acordeonador a more analog feeling, a large 4700uf electrolytic capacitor stores just enough energy to make the music generation more than an on/off affair. It’s a great effect, and it works well! Not being one to leave any details out, [Berna] prototyped the build on perf board and then covered the board in what appears to be an wood grained contact paper, giving it that 1970’s dual keyboard electric organ feel.

It really just goes to prove that a 555 project can be the source of a great time! Hackaday is rife with 555 projects, but if you enjoy this, be sure to check out The Most Important Device In the Universe, which is of course powered by a 555. Continue reading “CD Player Powered 555 Piano Goes Accordion To Plan”

3D Printed Generator Build Highlights The Scientific Method

Sometimes we build to innovate, and sometimes we build just to have the satisfaction of saying we made it ourselves. Yet there is another reason to construct something ourselves: To learn, just as [Fraens] has done with this 3D-printed generator. (Video, embedded below.)

[Fraens] starts off with a jig for winding the individual coils, but then the jig itself snaps into a the stator ring. The stator ring is sandwiched by two rotors which rotate on a brass shaft suspended by needle bearings. With the exception of the hardware, all the structural parts are 3d printed.

What really separates the generator build isn’t how it’s built, but rather how [Fraens] has put it to use as tool for learning and experimentation. By plotting input torque vs electrical output, [Fraens] is able to calculate efficiencies in multiple configurations, and has some interesting conclusions to share toward the end of the video. We appreciate how the documentation and analysis help iterate the design towards higher efficiency and will inform the next build.

With some more work, we can see this going straight into a Vertical Axis Wind Turbine or attached to a Pelton Wheel for an off-grid hydro-power setup. Thanks to [Shabab] for the great Tip!

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Magnetic Bearings Put The Spin On This Flywheel Battery

[Tom Stanton] is right about one thing: flywheels make excellent playthings. Whether watching a spinning top that never seems to slow down, or feeling the weird forces a gyroscope exerts, spinning things are oddly satisfying. And putting a flywheel to work as a battery makes it even cooler.

Of course, using a flywheel to store energy isn’t even close to being a new concept. But the principles [Tom] demonstrates in the video below, including the advantages of magnetically levitated bearings, are pretty cool to see all in one place. The flywheel itself is just a heavy aluminum disc on a shaft, with a pair of bearings on each side made of stacks of neodymium magnets. An additional low-friction thrust bearing at the end of the shaft keeps the systems suitably constrained, and allows the flywheel to spin for twelve minutes or more.

[Tom]’s next step was to harness some of the flywheel’s angular momentum to make electricity. He built a pair of rotors carrying more magnets, with a stator of custom-wound coils sandwiched between. A full-wave bridge rectifier and a capacitor complete the circuit and allow the flywheel to power a bunch of LEDs or even a small motor. The whole thing is nicely built and looks like a fun desk toy.

This is far from [Tom]’s first flywheel rodeo; his last foray into storing mechanical energy wasn’t terribly successful, but he has succeeded in making flywheels fly, one way or another.

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