Although there are several vertical axis wind turbines listed on greenterrafirma’s page, the one built with 55 gallon drums was especially interesting to us.  Although the spouse approval factor of any of these designs is debatable, at $100, the 55 gallon drum design could provide a very good return on investment.  The tools required to make one of these are relatively simple, so this could make this experiment accessible to those without a vast arsenal of equipment.

If large blue barrels aren’t your thing, the post also features several other turbine designs, including one made with wood and aluminium foil, and one constructed out of PVC pipe.  The video after the break does a good job of explaining the “blue barrel” construction process, but if you’d rather just see this [VAWT] in action, fast forward to 5:25.

If wind turbines aren’t your thing at all, why not instead build a heat exchanger to harvest the waste heat that your appliances give off anyway?

Add some fruit to your indoor bounty with this hydroponic strawberry farm. [Dino] whipped this up as his 45th hack a week episode (getting pretty close to his year-long goal). He used parts you probably already have sitting around the house somewhere. But even if you bought everything and used it once you still wouldn’t be out much.

A plastic storage container serves as the base. [Dino] also grabbed four identical plastic containers (large yogurt containers would work here) to host the plants. He cut off the bottom half and inserted some netting to keep the plant from falling through. After tracing the size of the container on the enclosure’s lid he cut out holes which will host each plant. This provides a way to dangle the roots into the nutrient solution which is kept oxygen rich with an aquarium pump and two air stones. It certainly deserves a place next to that salad farm you threw together. Don’t miss [Dino's] build video after the break.

[Yuhin Wu] wrote in to let us know about the Automated Recycling Sorter that was built with a group of classmates at the University of Toronto. They entered it the school’s student design contest and we’re happy to report that it took first place.

The angled sled has been designed to separate glass, plastic, and metal containers. The first sorting happens at the intake area. A set of moment arms are used to weed out the glass bottles. Since there are several of them in a row, a larger and heavier plastic container will not be falsely sorted and the same goes for smaller glass bottles.

With the glass out of the mix the team goes on to separate metal and plastic. An Arduino was used for this purpose. It senses an electrical disturbance caused by a metal can passing through the chute and actuates a trap door to sort it. Plastic has no effect on this sensor and slides past the trap to its own sorting bin.

Don’t miss both demo videos which we’ve included after the break.

[Mathieu] just finished analyzing the numbers from a month of solar energy harvesting. You may remember that he was curious to see what kind of energy can be collected from small solar cells used indoors. He built several copies of a test platform which collected data between December 16th and January 16th.

First of all, it’s not shocking to find out that rooms with no sunlight produced negligible energy during that time. When you think about it, if they had been gathering a statistically significant amount wouldn’t that mean the lighting used in those rooms was incredibly inefficient? In other words, there’s no way you need to be making that much light.

But he did find that proper positioning in rooms that catch sunlight during the day can result in usable energy for small loads. He established that a 0.5 Watt panel harvested just a bit more than half of what a 1 Watt panel did. But perhaps the most useful discovery was that it’s quite a bit more efficient to have a charging circuit store energy in a battery rather than directly powering a fixed load.

It will take us a few more viewings to really decide what we can take away from the experiment for our own projects. But we appreciate [Mathieu's] quest for knowledge and his decision to put this information out there so that others can learn from it.

[Mathieu] was interested in using more solar cells for his everday electronics. He looked around but couldn’t find much information about using pholovoltaic for small indoor devices. We remember hearing some of the same things from [Dave Jones] in one of his EEVblog installments from a few years ago which looked at solar calculators; the only indoor solar gadget we can think of.

The quest for knowledge was on and [Mathieu] decided to build this indoor solar cell test platform. It’s a stable piece of hardware that allows him to run reliable tests in many different conditions. It’s designed to compare two identical cells. One is charging the Lithium cell, the other is driving a load directly. A second battery powers the platform separately from the solar circuits so that it can be used as a data logger. He collects, dumps, and graphs info from his test runs, then discusses his findings. We won’t spoil it, but the results are not great. Mostly you need sunlight to get real results as it’s just so much more powerful than artificial lighting.

Here’s a photovoltaic cell that can be printed onto paper. The manufacturing technique is almost as simple as using an inkjet printer. The secret is in the ink itself. It takes five layers deposited on the paper in a vacuum chamber. But that’s a heck of a lot easier than current solar cell fabrication practices. In fact, is sounds like the printing process is very similar to how potato chip bags are made. This is significant, because it could mean a fast track to mass production for the technology.

It isn’t just the easy printing process that excites us. Check out the video after the break where a test cell is placed on top of a light source while being monitored by a multimeter. It’s been folded like a fan and you can see a researcher sinch up the cell into a small form for storage. It’s a little counter-intuitive; for instance, you wouldn’t want to make a window shade out of it because it would have to be down during the day to get power. Be we think there’s got to be some great use for these foldable properties.

[Thanks Rob]

With grand plans of tenting out for several days at a music festival [Josh] needed a way recharge his portable devices. In the past he’s lugged around a 12V battery with him, but this year he wanted to make things easier. He ended retrofitting a camping light to do the job with the help of the summer sun.

The first step of the project was to source some rechargeable batteries. He toyed with the idea of Li-Ion cells but ended up going with NiMH because the charging is more forgiving and he got them at a great price. Because of the lower operating voltage (1.2V versus Alkaline’s 1.5V) he needed to squeeze two more into the lamp housing. Here you can see that he just managed to get them to fit in the wire-run area down the middle of the case.

Next comes the recharging circuit. He based his design around an ATmega44, using a voltage divider and the ADC to detect when the batteries are topped off. During the day this is connected to an external solar panel and it’s ready to charge his phone when he gets back at night.

Looks like New York’s fire brigade confiscated all of the gas (or bio-diesel) generators from Occupy Wall Street protesters in Zuccotti Park. Apparently the Fire Chief cites the generators as a fire hazard. This seems a dubious claim. One of the shots in the video after the break clearly shows fire extinguishers close at hand, but we’re no experts on fire code. We’d bet the concern is having combustibles around if the scene turns violent… or just wanting to pressure the group with the loss of a heat source.

Instead of going without, the movement received help from a neighboring protest group in Boston. Bicycle power replaces the missing generators as volunteers pedal to produce electricity. Students from MIT plied their skills to help design multiple charging stations that can be used by the community. It won’t be enough to provide heat for the ongoing occupiers, but it does let them charge their electronic devices which helps ensure that current information is still flowing out of this epicenter of activity.

Does anyone have any ideas for hacking up a heat source that won’t ruffle the feathers of local officials? If so, leave a comment. And if you’ve already got a post written up on the topic don’t be afraid to send in a tip about it.

[Thanks 1116 Birchmont]

As soon as the team at Revolt Labs heard Occupy Wall Street was coming to Boston, they decided to pick up their soldering irons in support of the throngs of protestors. They came up with a Solar charging USB box to keep those cell phones and digital cameras charged.

The case came direct from an Army surplus store. Originally, the box was used by the Dutch military to test the air for poison gas and signal when it was safe to remove a gas mask – hopefully not a portent of things to come.

On top of the box is five solar panels that output two watts each. A bit of breadboard holds a 7805 voltage regulator, a few caps and a diode. This regulated output goes to a USB hub and provides power for recharging.

For a cheap and easy project for our brothers without arms, we couldn’t think of a better project for the Occupy Boston tent city. Of course heating units will be needed at the Occupy protests this winter, but at least now the protesters have the means to power their communications equipment.

update: Once again, this has devolved into political argument and name calling. We, as hackaday, really couldn’t care less which party you are for or what your political beliefs are. We want to talk about the project, in this case a portable solar charger. We go to other sites to argue politics. Maybe you should try here.

We often look at battery-operated hardware and shake our heads at the wastefulness of throwing away disposable batteries. There are some devices that minimize the waste, like those TV remotes that seem to never need new cells. But the C cells that [Quinn Dunki] kept replacing in her elliptical trainer were only lasting about three months at a time. The manufacturer hadn’t cared enough to build a power jack into the machine, so she built her own AC adapter without modifying the stock hardware.

The first thing she did was to patch in a couple of wires between two of the batteries. This let her measure the current consumption, which topped out at around 200mA. This is good news because that’s easily sourced with a cheap linear regulator. Out of the junk box came a 12V/1A wall wart transformer, which just leaves the need for a fuse and some capacitors to finish out a voltage regulator circuit.

Since [Quinn] didn’t want to permanently alter the exerciser, she came up with a way that it could take the same physical space as the batteries. Two long stand-offs are used as prongs to interface the spring terminals in the battery compartment. They attach to a piece of protoboard which hosts the rest of the circuitry. Now she just needs to remember to unplug this from the wall after each session and she’ll be in business.

With a little bit of thought put into the build, a wind turbine generator can be one of the greenest ways to generate electricity. Wind power doesn’t require a semiconductor fab lab (unlike solar panels) and doesn’t have very many environmental consequences (unlike hydro power). The Tech Junkies put up a build log of a wind turbine that ended up being a very easy build.

In the interests of sustainability, The Tech Junkies found an old 1.5 HP DC treadmill motor. After measuring the voltage output when the motor was connected to a lathe, they discovered the power output was very linear. With a little bit of calculations, they realized they needed about 1000 RPM to get 20 Volts out of the motor. The team connected an inverter (it’s always cool seeing a power meter run backwards) and started fabricating the blades.

The team found a wealth of info on blade design on this site and following a few guidelines made six blades out of 8″ diameter PVC pipe. An aluminum hub was fabricated and the whole shebang was put on top of a found steel frame.

The Tech Junkies’ build produces 10 Watts of power but they’re looking to increase that to 500 W with the appropriate gearing. A great build that harkens back to this awesome webpage about turbine building and living off the grid.

Here we see [Christopher Suprock] hanging out in his basement laundry area in order to show off his intelligent heat exchanger. The reason for the device is simple, when you use your clothes dryer , hot water heater, other other utilities that generate heat, energy is often wasted in the form of hot exhaust gases. Why not get the most for you clothes drying dollar by sourcing that hot air to warm your house.

The block you see on top of the dryer is a heat exchanger. The exhaust from the dryer passes through a radiator assembly before being vented outside the house. Some control hardware monitors the temperature of the input side and switches on the fan when it detects a higher temperature than the ambient air. Air then flows through the radiator, picking up heat energy from the exhaust gas. See [Christopher's] explaination, and some thermal readings while the dryer is running, in the video after the break.

This makes us wonder, if the heat exchanger drops the exhaust gas fifty degrees before being vented, will this cause any issues with condensation?

Yes. That’s a motorized tricycle with a toilet. Let that sink in for a minute. Oh, that isn’t a concept sketch of something that will never be built. The Toilet Bike Neo is most assuredly a real thing.

Biogas, or methane produced from decaying plant or animal wastes, is a legitimate form of energy. Waste gasses from landfills make up about half a percent of U.S. natural gas consumption. The state of Vermont even has a Cow Power program of renewable energy. That being said, this is a toilet on a trike.

The bike was built for Japanese bathroom fixture manufacturer TOTO’s green initiative. Biogas is produced onboard the trike, so instead of going to the local gas station to fill up, you could just get a newspaper, coffee and bran muffin. There are tanks on the back of the trike containing “fuel”. This arrangement probably makes a rear end collision in the Toilet Bike Neo more terrifying than getting rear-ended in a Ford Pinto.

The Toilet Bike Neo is setting off on a trip across Japan on October 6th (today) to promote biogas. You can follow the updates on the Toilet Bike Neo’s Twitter.

A tip ‘o the hat to [jon] for sending this one in. You may now commence the jokes.

Here’s a project that’s hard to categorize. It generates electricity by burning wood. The diamond-plate wrapped column to the right is a magazine that stores the wood, which is gravity fed as pieces below are consumed. The heat is used to drive a power turbine which is responsible for generating the electricity.

This begs the question, is this a sustainability hack? From one perspective it’s burning renewable biomass. Right now that’s wood, but it could be compressed blocks of grasses or wood manufacturing byproducts. So in this sense it is sustainable. Unfortunately it still doesn’t solve the problem of carbon emissions.

The build log for the project is both image and video heavy. You can see the initial prototypes which are not self-feeding, but burn so hot that there’s a nice pink glow to the entire assembly. But by the time they get to the final prototype it’s running much more efficiently, and can put out a peak of over 100 amps!

[Thanks DerAxman]

Sometimes you don’t need a lot of horsepower to win a speed record. In a fluke of no one else competing in the alt fuel class,  [John]‘s biodiesel motorcycle set a new land speed record at the LTA event last summer.

[John]‘s bike is a junkyard 1978 Kawasaki KZ400. The stock engine was replaced with a Chinese knock off of a Yanmar air-cooled diesel motor. The fuel is regular old vegetable oil. From the looks of the exhaust, we’re assuming [John]‘s garage has a rich french fry smell to it.

Compared to highway speeds, [John]‘s runs for a land speed record are a little absurd – a nice bonus when you’re the only driver in your class. The first pass of 42 mph was a little disappointing, so [John] removed the fender, tail light and brakes. After all the unnecessary weight was removed, the top speed – and new record – was 56.5 mph.

Converting a diesel car to run on french fry oil is great and a lot better for the environment than burning liquefied dinosaurs. In any event, a green motorcycle is a lot better than 2000 pounds of automobile moving less than 200 pounds of person. Check out a few of [John]‘s land speed runs after the break.