This Little Piggy Stayed Home And Became A Stove

February 25, 2014 by 11 Comments

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This little piggy probably should have gone to the market. Instead, its become an extremely decorative, and cute, wood burning stove!

After being inspired by a similar Instructable that guides you through the creation of a wood stove using an expired gas cylinder, [Ruudvande] had to try it himself. The problem was — he didn’t have a gas tank. Luckily for him, he found someone who did, but as it turned out, they wanted to turn it into a barbecue! So, slightly sidetracked, he built them a barbecue using the center of the cylinder, and got to keep the ends and enough steel to make Mr. Piggy himself.

Almost the entire wood burning stove is made of scrap bits and pieces of steel, and various pieces of mounting hardware. Armed with just a MIG welder, [Ruudvande] welded it together all by hand, and we think it turned out great! He’s not quite happy with it yet though and plans to upgrade the chimney, put a larger grill inside, paint it, and even add a glass window to the door.

Monitoring Air Quality With A $12 Sensor

April 19, 2012 by 24 Comments

[Chris] has allergies, asthma, and uses a wood burning stove. You can imagine why testing his air quality might be something he’d be interested in. He has a very nice $290 laser particle counter, but was really curious how the $12 sharp sensor he found would stack up. To find out, he plugged it into an arduino and started logging both on pachube.

After a few different tests, like lighting a match, blowing it out, and letting the smoke flow into the sensors, he decided he needed something better. Cooking some pancakes turned out to be his ultimate method. After charting the dissipation of particles after cooking a nice batch of griddle cakes, he found the two sensors to be surprisingly similar.

Sleeping Rough In Alaska With A USPS Cargo Bike

January 4, 2026 by 31 Comments

Out of all 49 beautiful US states (plus New Jersey), the one you’d probably least want to camp outside in during the winter is arguably Alaska. If you were to spend a night camping out in the Alaskan winter, your first choice of shelter almost certainly wouldn’t be a USPS electric cargo trike, but over on YouTube [Matt Spears] shows that it’s not that hard to make a lovely little camper out of the mail bike. 

We’re not sure how much use these sorts of cargo trikes get in Alaska, but [Matt] seems to have acquired this one surplus after an entirely-predictable crash took one of the mirrors off. A delta configuration trike — single wheel in front — is tippy at the best of times, but the high center of gravity you’d get from a loading the rear with mail just makes it worse. That evidently did not deter the United States Postal Service, and it didn’t deter [Matt] either.

His conversion is rather minimal: to turn the cargo compartment into a camper, he only adds a few lights, a latch on the inside of the rear door, and a wood-burning stove for heat. Rather than have heavy insulation shrink the already-small cargo compartment, [Matt] opts to insulate himself with a pile of warm sleeping bags. Some zip-tie tire chains even let him get the bike moving (slowly) in a winter storm that he claims got his truck stuck.

While it might not be a practical winter vehicle, at least on un-plowed mountain roads, starting with an electric-assist cargo trike Uncle Sam already paid for represented a huge cost and time savings vs starting from scratch like this teardrop bike camper we featured a while back. While not as luxurious, it seems more practical for off-roading than another electric RV we’ve seen.

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Smelly Ultrasound

November 24, 2025 by 26 Comments

We aren’t sure why, but [Lev Chizhov] and some other researchers have found a way to make you smell things by hitting your head with ultrasound. Apparently, your sense of smell lives in your olfactory bulb, and no one, until now, has thought to try zapping it with ultrasound to see what happens.

The bulb is somewhere behind your nose, as you might expect. This is sub-optimal for ultrasound because your nose isn’t flat, and it is full of air. Packing a subject’s nose with gel wasn’t going to win many fans. The answer was to place the transducer on the person’s forehead and shoot down at the bulb. They made a custom headset that let them precisely target areas of the subject’s bulb guided by an MRI.

So far, they have a sample size of two, but they’ve managed to induce the smell of fresh air, garbage, ozone, and burning wood. What would you do with this? Smell-o-vision? A garbage truck VR game? Let us know in the comments. We don’t think this is exactly how the last VR smell gadget we saw worked, but — honestly — we aren’t completely sure.

Mining And Refining: Drilling And Blasting

June 24, 2025 by 24 Comments

It’s an inconvenient fact that most of Earth’s largesse of useful minerals is locked up in, under, and around a lot of rock. Our little world condensed out of the remnants of stars whose death throes cooked up almost every element in the periodic table, and in the intervening billions of years, those elements have sorted themselves out into deposits that range from the easily accessed, lying-about-on-the-ground types to those buried deep in the crust, or worse yet, those that are distributed so sparsely within a mineral matrix that it takes harvesting megatonnes of material to find just a few kilos of the stuff.

Whatever the substance of our desires, and no matter how it is associated with the rocks and minerals below our feet, almost every mining and refining effort starts with wresting vast quantities of rock from the Earth’s crust. And the easiest, cheapest, and fastest way to do that most often involves blasting. In a very real way, explosives make the world work, for without them, the minerals we need to do almost anything would be prohibitively expensive to produce, if it were possible at all. And understanding the chemistry, physics, and engineering behind blasting operations is key to understanding almost everything about Mining and Refining.

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Multi-stage steam turbine with turbo generator (rear, in red) at the German lignite plant Boxberg (Credit: Siemens AG)

How Supercritical CO2 Working Fluid Can Increase Power Plant Efficiency

April 22, 2025 by 42 Comments

Using steam to produce electricity or perform work via steam turbines has been a thing for a very long time. Today it is still exceedingly common to use steam in this manner, with said steam generated either by burning something (e.g. coal, wood), by using spicy rocks (nuclear fission) or from stored thermal energy (e.g. molten salt). That said, today we don’t use steam in the same way any more as in the 19th century, with e.g. supercritical and pressurized loops allowing for far higher efficiencies. As covered in a recent video by [Ryan Inis], a more recent alternative to using water is supercritical carbon dioxide (CO2), which could boost the thermal efficiency even further.

In the video [Ryan Inis] goes over the basics of what the supercritical fluid state of CO2 is, which occurs once the critical point is reached at 31°C and 83.8 bar (8.38 MPa). When used as a working fluid in a thermal power plant, this offers a number of potential advantages, such as the higher density requiring smaller turbine blades, and the potential for higher heat extraction. This is also seen with e.g. the shift from boiling to pressurized water loops in BWR & PWR nuclear plants, and in gas- and salt-cooled reactors that can reach far higher efficiencies, as in e.g. the HTR-PM and MSRs.

In a 2019 article in Power the author goes over some of the details, including the different power cycles using this supercritical fluid, such as various Brayton cycles (some with extra energy recovery) and the Allam cycle. Of course, there is no such thing as a free lunch, with corrosion issues still being worked out, and despite the claims made in the video, erosion is also an issue with supercritical CO2 as working fluid. That said, it’s in many ways less of an engineering issue than supercritical steam generators due to the far more extreme critical point parameters of water.

If these issues can be overcome, it could provide some interesting efficiency boosts for thermal plants, with the caveat that likely nobody is going to retrofit existing plants, supercritical steam (coal) plants already exist and new nuclear plant designs are increasingly moving towards gas, salt and even liquid metal coolants, though secondary coolant loops (following the typical steam generator) could conceivably use CO2 instead of water where appropriate.

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Why Physical Media Deserved To Die

April 22, 2025 by 137 Comments

Over the course of more than a decade, physical media has gradually vanished from public view. Once computers had an optical drive except for ultrabooks, but these days computer cases that even support an internal optical drive are rare. Rather than manuals and drivers included on a data CD you now get a QR code for an online download. In the home, DVD and Blu-ray (BD) players have given way to smart TVs with integrated content streaming apps for various services. Music and kin are enjoyed via smart speakers and smart phones that stream audio content from online services. Even books are now commonly read on screens rather than printed on paper.

With these changes, stores selling physical media have mostly shuttered, with much audiovisual and software content no longer pressed on discs or printed. This situation might lead one to believe that the end of physical media is nigh, but the contradiction here comes in the form of a strong revival of primarily what used to be considered firmly obsolete physical media formats. While CD, DVD and BD sales are plummeting off a cliff, vinyl records, cassette tapes and even media like 8-track tapes are undergoing a resurgence, in a process that feels hard to explain.

How big is this revival, truly? Are people tired of digital restrictions management (DRM), high service fees and/or content in their playlists getting vanished or altered? Perhaps it is out of a sense of (faux) nostalgia?

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