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An image of a desert with dramatically cloudy skies. In the middle of the image is a series of clay doorways with vertically-oriented wooden slats surrounding a central pole. These form the basis of a panemone windmill.

Help Wanted: Keep The World’s Oldest Windmills Turning

November 7, 2024 by 36 Comments

While the Netherlands is the country most known for its windmills, they were originally invented by the Persians. More surprisingly, some of them are still turning after 1,000 years.

The ancient world holds many wonders of technology, and some are only now coming back to the surface like the Antikythera Mechanism. Milling grain with wind power probably started around the 8th Century in Persia, but in Nashtifan, Iran they’ve been keeping the mills running generation-to-generation for over 1000 years. [Mohammed Etebari], the last windmill keeper is in need of an apprentice to keep them running though.

In a world where vertical axis wind turbines seem like a new-fangled fad, it’s interesting to see these panemone windmills are actually the original recipe. The high winds of the region mean that the timber and clay structure of the asbad structure housing the turbine is sufficient for their task without all the fabric or man-made composites of more modern designs. While drag-type turbines aren’t particularly efficient, we do wonder how some of the lessons of repairability might be used to enhance the longevity of modern wind turbines. Getting even 100 years out of a turbine would be some wicked ROI.

Wooden towers aren’t just a thing of the past either, with new wooden wind turbines soaring 100 m into the sky. Since you’ll probably be wanting to generate electricity and not mill grain if you made your own, how does that work anyway?

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Universal Power Bank Customized To Your Liking

August 31, 2024 by 10 Comments

One of the most troubling trends of almost every modern consumer product that uses electricity is that the software that controls the product is likely to be proprietary and closed-source, which could be doing (or not doing) any number of things that its owner has no control over. Whether it’s a computer, kitchen appliance, or even a device that handles the electricity directly, it’s fairly rare to find something with software that’s open and customizable. That’s why [Traditional-Code9728] is working on a power bank with an open-source firmware.

From a hardware perspective the power bank is fairly open as well, with a number of options for connecting this device to anything else that might need power. It sports a bidirectional USB-C port as well as a DC barrel plug, either of which can either charge other devices or receive energy to charge its own battery. These ports can also accept energy from a solar panel and have MPPT built in. There’s also dual USB-A ports which can provide anywhere from five to 12 volts at 25 watts, and a color screen which shows the current status of the device.

While this is a prototype device, it’s still actively being worked on. Some future planned upgrades to the power bank include a slimmer design, charge limiting features to improve battery life, and more fine-tuned control of the output voltage and current on the USB-C port. With all of the software being open-source, as well as the circuit diagram and 3D printing files, it could find itself in plenty of applications as well. This power bank also stays under the energy limits for flying on most commercial airlines as well, but if you don’t plan on taking your power bank on an airplane then you might want to try out this 2000-watt monster instead.

USB-C Powered Hotplate Is Not For Food

July 25, 2024 by 17 Comments

Once upon a time, it was deemed mostly silly to try and schlep power from a computer’s ports. Then it was kind of amusing to do so with USB, and before you knew it, we were running whole laptops off what started out as a data connector. These days, it’s not unusual to run a soldering iron off USB-C, or, as [MarkTheQuasiEngineer] has done—a hotplate!

This hotplate is not for quesadillas, nor samosas. Instead, it’s a tiny hotplate for tiny reflow tasks. Given many PCBs are quite small, there’s no need for a huge hot plate to get your circuits assembled.

The device relies on metal ceramic heating elements to provide the warmth. An NTC thermistor is used for monitoring the temperature for accurate control, which is handled by the STM32 microcontroller that’s running the show. It also drives a small display indicating the mode of operation and current temperature. The STM32 controls the power going to the heating element from the USB-C feed with a stout power MOSFET.

Sadly, the project hasn’t been a complete success. With a PCB on the plate, [MarkTheQuasiEngineer] was only able to achieve peak temperatures of around 200 C. That’s not great for doing proper reflow, but it’s a start. He believes upgrading to a more powerful supply to feed the hotplate will help.

We’ve featured some other great reflow hotplates before too.
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Flipped Transformer Powers Budget-Friendly Vacuum Tube Amp

November 7, 2023 by 31 Comments

If you’ve ever wondered why something like a radio or a TV could command a hefty fraction of a family’s yearly income back in the day, a likely culprit is the collection of power transformers needed to run all those hungry, hungry tubes. Now fast-forward a half-century or more, and affordable, good-quality power transformers are still a problem, and often where modern retro projects go to die. Luckily, [Terry] at D-Lab Electronics has a few suggestions on budget-friendly transformers, and even shows off a nice three-tube audio amp using them.

The reason transformers were and still are expensive has a lot to do with materials. To build a transformer with enough oomph to run everything takes a lot of iron and copper, the latter of which is notoriously expensive these days. There’s also the problem of market demand; with most modern electronics favoring switched-mode power supplies, there’s just not a huge market for these big lunkers anymore, making for a supply and demand equation that’s not in the hobbyist’s favor.

Rather than shelling out $70 or more for something like a Hammond 269EX, [Terry]’s suggestion is to modify an isolation transformer, specifically the Triad N-68X. The transformer has a primary designed for either 120 or 230 volts, and a secondary that delivers 115 volts. Turn that around, though, and you can get 230 volts out from the typical North American mains supply — good enough for the plate supply on the little amp shown. That leaves the problem of powering the heaters for the tubes, which is usually the job of a second 6- or 12-volt winding on a power transformer. Luckily, the surplus market has a lot of little 6.3-volt transformers available on the cheap, so that shouldn’t be a problem.

We have to say that the amp [Terry] put these transformers to work in sounds pretty amazing — not a hint of hum. Good work, we say, but we hope he has a plan in case the vacuum tube shortage gets any worse.

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Sailor Hat Adds Graceful Shutdown To Pis

September 18, 2023 by 45 Comments

Even though Windows and other operating systems constantly remind us to properly eject storage devices before removing them, plenty of people won’t heed those warnings until they finally corrupt a drive and cause all kinds of data loss and other catastrophes. It’s not just USB jump drives that can get corrupted, though. Any storage medium can become unusable if certain actions are being taken when the power is suddenly removed. That includes the SD cards on Raspberry Pis, too, and if your power isn’t reliable you might consider this hat to ensure they shut down properly during power losses.

The Raspberry Pi hat is centered around a series of supercapacitors which provide power for the Pi temporarily. The hat also communicates with the Pi to let it know there is a loss of power, so that the Pi can automatically shut itself down in that situation to prevent corrupting the memory card. The hat is more than just a set of backup capacitors, though. The device is capable of taking input power from a wide range of sources and filtering it for the power requirements of the Pi, especially in applications like boats and passenger vehicles where the input power might be somewhat noisy. There’s an optocoupled CAN bus interface as well for those looking to use this for automotive applications.

The entire project is also available on the project’s GitHub page for those wishing to build their own. Some sort of power backup is a good idea for any computer, though, not just Raspberry Pis. We’ve seen uninterruptible power supplies (UPS) with enough power to run an entire house including its computers, to smaller ones that’ll just keep your Internet online during a power outage.

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Converting Wind To Electricity Or: The Doubly-Fed Induction Generator

August 30, 2023 by 97 Comments

Humanity has been harvesting energy from the wind for centuries. The practice goes back at least to 8th century Persia where the first known historical records of windmills came, but likely extends even further back than that. Compared to the vast history of using wind energy directly to do things like mill grain, pump water, saw wood, or produce fabrics, the production of electricity is still relatively new. Despite that, there are some intriguing ways of using wind to produce electricity. Due to the unpredictable nature of wind from moment to moment, using it to turn a large grid-tied generator is not as straightforward as it might seem. Let’s take a look at four types of wind turbine configurations and how each deal with sudden changes in wind speeds. Continue reading “Converting Wind To Electricity Or: The Doubly-Fed Induction Generator” →

QSPICE Picks Up Where LTSpice Left Us

August 25, 2023 by 23 Comments

[Mike Engelhardt] is a name that should be very familiar to the hardcore electronics nerd. [Mike] is the developer responsible for LTSpice, which is quite likely the most widely used spice-compatible simulator in the free software domain. When you move away from digital electronics and the comfort of software with its helpful IDEs and toolchains, and dip a wary toe into the murky grey waters of analog or power electronics, LTSpice is your best friend. And, like all best friends, it’s a bit quirky, but it always has your back. Sadly, LTSpice development seems to have stalled some years ago, but luckily for us [Mike] has been busy on the successor, QSpice, under the watchful eye of Qorvo.

It does look in its early stages, but from a useability point of view, it’s much improved over LTSpice. Performance is excellent (based on this scribe’s limited testing while mobile.) Gone (thankfully!) is the uncommon verb-noun usage paradigm — replaced with a more usual cut-n-paste flow. Visually it still kind of looks like LTspice in places, but nicer with a clear and uncluttered design that gets straight to the point. Internally, the simulation engine has improved in speed and accuracy, as well as adding native support for modern semiconductor types, such as wide bandgap materials like SiC. Noted is that this updated software has a particular emphasis on power integrity and noise analysis, which are sticky problems that have a big impact on modern high-power systems.

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