Bad Experiences With A Cheap Wind Turbine

April 20, 2024 by Lewin Day 44 Comments

If you’ve got a property with some outdoor space and plenty of wind, you might consider throwing up a windmill to generate some electricity. Indeed, [The Broject List] did just that. Only, his experience was a negative one, having purchased a cheap windmill online. He’s warning off others from suffering the same way by explaining what was so bad about the product he bought.

The windmill in question was described as a “VEVOR Windturbine”, which set him back around 100 euros, and claimed to be capable of producing 600 watts at 12 volts. He starts by showing how similar turbines pop up for sale all over the Internet, with wildly inflated specs that have no relation to reality. Some sellers even charge over 500 euros for the same basic device.

He then demonstrates the turbine operating at wind speeds of approximately 50 km/h. The output is dismal, a finding also shared by a number of other YouTube channels out there. Examining the construction of the wind turbine’s actual generator, he determines that it’s nowhere near capable of generating 600 watts. He notes the poorly-manufactured rotor and aluminium coils as particular disappointments. He concludes it could maybe generate 5 watts at most.

Sadly, it’s easy to fall into this trap when buying online. That’s where it pays to do your research before laying down your hard-earned cash. Continue reading “Bad Experiences With A Cheap Wind Turbine” →

Giant Sails Actually Help Cargo Ships Save Fuel, And The Planet In Turn

April 2, 2024 by Lewin Day 81 Comments

Shipping is not a clean business. The global economy is fueled by trade, and much of that trade involves hauling product from point A to point B. A great deal of that product goes by water. Shipping it around uses a great deal of fuel, and creates a great deal of greenhouse gas emissions. It’s bad for the environment, and it’s costly for shipping companies.

Any gain in efficiency can be an edge in this regard, and beneficial for the planet to boot. Now, it appears that good old fashioned sails might just be the tool that companies need to clean up their fleets. And it’s not some theory—real world numbers back it up!

Where The Wind Takes You

Sea transport has been branded as a significant contributor to global greenhouse gas emissions, accounting for about 3% of the total. Shipping companies in turn are under increasing pressure to innovate and adapt, both for the good of the planet and their own coffers. It’s perhaps a small blessing that saving fuel and slashing emissions go hand in hand, and companies are desperate for any technology that can deliver on those goals.

Enter the WindWings, a revolutionary “wind assisted propulsion” concept developed by BAR Technologies. In partnership with ocean freight firm Cargill, these radical sails were installed aboard the Pyxis Ocean, a Kamsarmax bulk carrier chartered from Mitsubishi. These aren’t the canvas and rope constructs of yore . Instead, they’re a set of towering metal sails that stand 123 feet tall, designed to harness the wind’s power and propel the massive bulk carrier across the oceans. Continue reading “Giant Sails Actually Help Cargo Ships Save Fuel, And The Planet In Turn” →

These Keycaps Are 100% Recycled Plastic

March 20, 2024 by Kristina Panos 4 Comments

Artisan keycaps are generally meant to replace your Escape key, though they can be used anywhere you like (as long as they fit, of course). Keycap maker [tellybelly] of jankycaps has been experimenting with making keycaps out of 100% recycled plastic, and offers an interesting post detailing their development and production process.

What do you do when normal injection molding tooling is out of your budget, and silicone molds simply won’t do? You turn to 3D printing if you can. In this case, [tellybelly] and company found a resin designed to withstand high temperatures.

[tellybelly] was able to design the mold using a plethora of online resources, and even verified the flow using a special program. Although the first two versions worked, they had some flaws. Third time’s the charm, though, and then it was time to sort plastic and fire up the shredder.

After heating up the shreds to 200 °C or so, it was time to start the injecting. This part isn’t exactly a cakewalk — mixing different plastics together can vary the workable temperature range that doesn’t degrade the plastic. Although it sounds like the end, [tellybelly] reports that they spent just as much time here as they did at the drawing board, experimenting with pressure on the mold, various cool-down methods, and how long to wait before opening the mold.

Via reddit

A Smarter Solar Water Heater

February 25, 2024 by Bryan Cockfield 79 Comments

Installing solar power at a home is a great way to reduce electricity bills, especially as the cost of solar panels and their associated electronics continue to plummet. Not every utility allows selling solar back to the grid, though, so if you’re like [Rogan] who lives in South Africa you’ll need to come up with some clever tricks to use the solar energy each day while it’s available to keep from wasting any. He’s devised this system for his water heater that takes care of some of this excess incoming energy.

A normal water heater, at least one based on electric resistive heaters, attempts to maintain a small range of temperatures within the insulated tank. If the temperature drops due to use or loss to the environment, the heaters turn on to bring the temperature back up. This automation system does essentially the same thing, but allows a much wider range of temperatures depending on the time of day. Essentially, it allows the water heater to get much hotter during times when solar energy is available, and lets it drop to lower values before running the heater on utility electricity during times when it isn’t. Using a combination ESP32 and ATtiny to both control the heater and report its temperature, all that’s left is to program Home Assistant to get the new system to interact with the solar system’s battery charge state and available incoming solar energy.

While it’s an elegantly simple system that also affords ample hot water for morning showers, large efficiency gains like this can be low-hanging fruit to even more home energy savings than solar alone provides on paper. Effectively the water heater becomes another type of battery in [Rogan]’s home, capable of storing energy at least for the day in the form of hot water. There are a few other ways of storing excess renewable energy as well, although they might require more resources than are typically available at home.

A large, short set of tree stumps supports many smaller, straight trees atop them. They are on a picturesque mountain with a orange deciduous tree behind them.

Daisugi – Growing Straight Lumber Without Killing The Tree

February 20, 2024 by Navarre Bartz 30 Comments

In 14th Century Japan, there was a shortage of straight lumber for building and flat land on which to grow it. Arborists there developed a technique that looks like growing trees on top of trees, called daisugi.

Similar to the European practice of pollarding for firewood and basket materials, daisugi has been likened to bonsai on steroids. Starting with a Japanese cedar tree, one chops the top off the tree once it has grown to sufficient size to survive this initial shock. The following spring, you start carefully guiding the new growth through pruning to create tall, straight trunks on top of the “platform cedar.” Pruning takes place approximately every two years and harvesting every twenty. A daisugi tree can produce new shoots for several hundred years if properly maintained.

Although often used as a decorative technique today, it seems like an interesting way to grow your own perfect lumber if you have the room for it. We suspect the technique could be used on other species that lend themselves to pollarding like oak or maple, but harvest times and reliable straight trunks might vary. With sustainable production of wood for cross-laminated timber (CLT) and other advanced timbers being of growing importance, we wonder if these techniques could make a comeback?

Continue reading “Daisugi – Growing Straight Lumber Without Killing The Tree” →

Open-Source Solar Modules

February 5, 2024 by Bryan Cockfield 13 Comments

As the price of solar panels continues to fall, more and more places find it economical to build solar farms that might not have been able to at higher prices. High latitude locations, places with more clouds than sun, and other challenging build sites all are seeing increased green energy development. The modules being used have one main downside, though, which is that they’re essentially a black box encased in resin and plastic, so if one of the small cells fails a large percentage of the panel may be rendered useless with no way to repair it. A solar development kit like this one from a group called Biosphere Solar is looking to create repairable, DIY modules that are completely open source, to help solve this issue.

The modular solar panel is made from a 3D printed holster which can hold a number of individual solar cells. With the cells placed in the layout and soldered together, they are then sandwiched between a few layers of a clear material like acrylic or glass with a seal around the exterior to prevent water intrusion. Since the project is open-source any number of materials can be used for the solar cell casing, and with the STL file available it’s not strictly necessary to 3D print the case as other manufacturing methods could be used. The only thing left is to hook up a DC/DC converter if you need one, and perhaps also a number of bypass and/or blocking diodes depending on your panel’s electrical layout.

The project is still in active development, and some more information can be found at the project’s website. While the “recyclability” of large-scale solar farms is indeed a problem, it’s arguably one which has been overblown by various interests who are trying to cast doubt on green energy. A small build like this won’t solve either problem anytime soon, so the real utility here would be for home users with small off-grid needs who want an open-source, repairable panel. It’s a great method to make sure solar technology is accessible and repairable for anyone that wants it, and in a way this approach to building hardware reminds us a lot of the Framework laptops.

Hacking A Xiaomi Air Purifier’s Filter DRM To Extend Its Lifespan

January 26, 2024 by Maya Posch 10 Comments

When [Unethical Info] was looking at air purifiers a while back, their eye fell on a Xiaomi 4 Pro, with a purchase quickly made. Fast-forward a while and suddenly the LCD on top of the device was showing a threatening ‘0% filter life remaining’ error message. This was traced back to an NFC (NTAG213) tag stuck to the filter inside the air purifier that had been keeping track of usage and was now apparently the reason why a still rather clean filter was forcibly being rejected. Rather than give into this demand, instead the NFC tag and its contents were explored for a way to convince it otherwise, inkjet cartridge DRM-style.

While in the process of reverse-engineering the system and doing some online research, a lucky break was caught in the form of earlier research by [Flamingo Tech] on the Xiaomi Air Purifier 3, who had obtained the password-generating algorithm used with the (password-locked) NFC tag, along with the target area of the filter’s NFC tag to change. Using the UID of the NFC tag, the password to unlock the NFC tag for writing was generated, which requires nothing more than installing e.g. ‘NFC Tools’ on an NFC-capable Android/iOS smartphone to obtain the tag’s UID and reset the usage count on the filter.

A password generating tool is provided with the [Unethical Info] article, and this approach works across a range of Xiaomi air purifiers, making it an easy fix for anyone who owns such a device but isn’t quite ready yet to shell out the big bucks for a fresh DRM-ed filter. This approach also saves one from buying more NFC tags, which was the case with the previous solution.