green hacks

809 Articles

Sensing Soil Moisture: You’re Doing It Wrong!

November 16, 2017 by 105 Comments

If you compulsively search online for inexpensive microcontroller add-ons, you will see soil moisture measurement kits. [aka] built a greenhouse with a host of hacked hardware including lights and automatic watering. What caught our attention among all these was Step 5 in their instructions where [aka] explains why the cheap soil sensing probes aren’t worth their weight in potting soil. Even worse, they may leave vacationers with a mistaken sense of security over their unattended plants.

The sensing stakes, which come with a small amplifier, work splendidly out of the box, but if you recall, passing current through electrodes via moisture is the recipe for electrolysis and that has a pretty profound effect on metal. [Aka] shows us the effects of electrolysis on these probes and mentions that damaged probes will cease to give useful information which could lead to overworked pumps and flooded helpless plants.

There is an easy solution. Graphite probes are inexpensive to make yourself. Simply harvest them from pencils or buy woodless pencils from the art store. Add some wires and hold them with shrink tube, and you have probes which won’t fail you or your plants.

Here’s some garden automation if this only whet your whistle, and here’s a robotic friend who takes care of the weeds for you.

Making Music With The Wind

October 21, 2017 by 18 Comments

[Niklas Roy] built a windmill-powered music box for his backyard, and it was so awesome all the neighbors wanted to take a picture of it. Someone even liked it so much that he stole [Niklas]’s windmill in the middle of the night. (We kind of don’t blame them, it’s a gorgeously clean build.)

In the past few weeks [Niklas] has been mass-producing 20 windmills for the KIKK Festival 2017 to be held in November in Namur, Belgium. The windmills will operate in a cluster, and all play “Für Elise” when the wind blows. However, each one is driven independently and so the music is asynchronous. Since he was building a bunch anyway, he built a replacement windmill for his backyard, and documented how to do it.

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Hackaday Prize Entry: Modular, Rapid Deployment Power Station

October 15, 2017 by 17 Comments

After a disaster hits, one obvious concern is getting everyone’s power restored. Even if the power plants are operational after something like a hurricane or earthquake, often the power lines that deliver that energy are destroyed. While the power company works to rebuild their infrastructure, [David Ngheim]’s mobile, rapid deployment power station can help get people back on their feet quickly. As a bonus, it uses renewable energy sources for power generation.

The modular power station was already tested at Burning Man, providing power to around 100 people. Using sets of 250 Watt panels, wind turbines, and scalable battery banks, the units all snap together like Lego and can fit inside a standard container truck or even the back of a pickup for smaller sizes. The whole thing is plug-and-play and outputs AC thanks to inverters that also ship with the units.

With all of the natural disasters we’ve seen lately, from Texas to Puerto Rico to California, this entry into the Hackaday Prize will surely gain some traction as many areas struggle to rebuild their homes and communities. With this tool under a government’s belt, restoration of power at least can be greatly simplified and hastened.

The HackadayPrize2017 is Sponsored by:

Typhoon-proof Wind Turbine

October 9, 2017 by 35 Comments

While wind energy is rapidly increasing its market share across the world, wind turbines are not able to be constructed everywhere that they might be needed. A perfect example of this is Japan, where a traditional wind turbine would get damaged by typhoons. After the Fukushima disaster, though, one Japanese engineer committed himself to building a turbine specifically for Japan that can operate just fine within hurricane-force winds. (YouTube, embedded below.)

The “typhoon turbine” as it is known works via the Magnus effect, where a spinning object directs air around it faster on one side than on the other. This turbine uses three Magnus effect-driven cylinders with a blade on each one, which allows the turbine to harvest energy no matter how high the wind speeds are. The problem with hurricanes and typhoons isn’t just the wind, but also what the wind blows around. While there is no mention of its impact resistance it certainly looks like it has been built as robustly as possible.

Hopefully this turbine is able to catch on in Japan so they can reduce their reliance on other types of energy. Wind energy has been getting incredibly popular lately, including among hikers who carry a portable wind generator, and even among people with just a few pieces of scrap material.

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Trading Bird Food For Cigarette Butts

October 9, 2017 by 98 Comments

Positive reinforcement is the process of getting someone to understand their actions result in a reward. Children get a sweet treat when they pick up all their toys and older ones might get some cash for mowing the lawn. From the perspective of the treat-giver, this is like turning treats into work. A Dutch startup wants to teach the crow population to pick up cigarette butts in exchange for bird treats.

The whole Corvidae family of birds is highly intelligent so it shouldn’t be a problem training them that they will get a reward for depositing something the Hominidae family regularly throw on the street where the birds live. This idea is in turn an evolution of the open-source Crow Box.

For some, leveraging the intelligence of animals is more appealing than programming drones which could do the same thing. A vision system mixed with a drone and a manipulator could fulfull the same function but animals are self-repairing and autonomous without our code. The irony of this project is that, although it’s probably fairly easy to train crows to recognize cigarette butts, the implementation hinges on having a vision system that can recognize the butts in order to properly train the crows in the first place.

If we had the time to train crows, it would definitely be to poop on cars that don’t signal for turns. Maybe some of these winged devices can be programmed to recognize lapses in traffic laws in exchange for some electrons.

Thank you, [jo_elektro], for the tip.

 

That Decentralised Low Voltage Local DC Power Grid, How Did It Do?

September 8, 2017 by 25 Comments

Early on in the year, Hackaday published one of its short daily pieces about plans from the people behind altpwr.net for a low voltage DC power grid slated for the summer’s SHACamp 2017 hacker camp in the Netherlands. At the time when it was being written in the chill of a Northern Hemisphere January the event seemed so far away, but as the summer fades away along with the deep tan many SHACamp attendees gained in the Dutch sunlight it’s worth going back and revisiting the project. Did they manage it, and how did they do? This isn’t really part of our coverage of SHACamp itself, merely an incidental story that happens to have the hacker camp as its theatre.  Continue reading “That Decentralised Low Voltage Local DC Power Grid, How Did It Do?” →

Harvesting Copper From Microwave Ovens

August 26, 2017 by 51 Comments

Obsolete appliances were once a gold mine of parts, free for the taking with a few snips of your diagonal cutters. Times have changed, though, and most devices yield only a paltry supply of parts, so much so that only by harvesting raw materials can you get much value out of them. And so we have this example of reclaiming copper from used microwave ovens.

The primary source of copper in most microwaves is the transformer, which we usually see re-tasked for everything from spot welders to material handling electromagnets. But the transformer is not the only source of the red metal; [eWaste Ben] also harvests it from relay coils and the main coil and shading coils of the fan motor.  The bounty is melted down in an electric foundry and cast in a graphite mold into a lovely ingot.

Unless you’re into repeatedly casting copper trinkets, a large bar of reclaimed copper might not be something you have a burning need to possess. But bearing in mind that copper can go for about $2.50 a pound at the scrap yard, there’s some money to be made, especially with dead microwaves essentially free for the taking. As [Ben] points out, taking the extra step to melt and cast the copper harvested from microwaves makes no sense if all you’re going to do is sell the scrap, but it’s nice to know how to do it just the same.

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