Solving Ultra High Vacuum Leaks Has An Elementary Solution

When we think of a vacuum leak we generally think of a car that just doesn’t want to run quite right. Most normally aspirated internal combustion engines rely on the vacuum created by the pistons to draw in the air fuel mixture that’s produced by the carburetor or fuel injection system. Identifying the leak usually involves spraying something combustible around common trouble areas while the engine is running. Changes to the engine speed indicate when the combustible gas enters the intake manifold and the leak can be found.

What if your vacuum leak is in a highly specialized piece of scientific equipment where the pressures are about 12 times orders of magnitude lower than atmospheric pressure, and the leak is so small it’s only letting a few atoms into the vacuum chamber at a time? [AlphaPhoenix] takes dives deep into this very subject in his video “Air-tight vs. Vacuum-tight.” which you can watch below the break.

Not only does [AlphaPhoenix] discuss how a perfect pressure vessel is sealed, he also explains the specialized troubleshooting methods used which turn out not to be all that different from troubleshooting an automotive vacuum leak- only in this case, several magnitudes more complex and elemental in nature.

We also enjoyed the comments section, where [AlphaPhoenix] addresses some of the most common questions surrounding the video: Torque patterns, the scarcity of the gasses used, and leaving well enough alone.

Does talking about vacuums get you pumped? Perhaps you’d enjoy such vacuum hacks as putting the toothpaste back in the tube in your homemade vacuum chamber.

Thank you [Morgan] for sending this one in. Be sure to send in your own hacks, projects, and fantastic finds through the Tip Line!

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Could Airships Make A Comeback With New Hybrid Designs?

Airships. Slow, difficult to land, and highly flammable when they’re full of hydrogen. These days, they’re considered more of a historical curiosity rather than a useful method of transport.

Hybrid Air Vehicles are a UK-based startup working to create a modern take on the airship concept. The goal is to create cleaner air transport for short-hop routes, while also solving many of the issues with the airship concept with a drastic redesign from the ground up. Their vehicle that will do all this goes by the name of Airlander 10. But is it enough to bring airships back to the skies?

A Hybrid Technology

Airlander 10 seen taking off during its first flight.

The Airlander 10 is not a lighter-than-air craft like traditional airships. Instead, the vehicle uses the buoyancy from its helium envelope to create only 60-80% of its lift. The rest of the left is generated aerodynamically by air passing over the eliptical shape of the airship’s body. This lift can also be further augmented by two diesel-powered ducted fans on the sides of the airship, which can pivot to assist with takeoff and landing. Two further fixed ducted fans on the rear provide the primary propulsion for the craft.

The hybrid approach brings several benefits over the traditional airship model. Chief among them is that as the Airlander 10 is heavier than air, it need not vent helium throughout flight to avoid becoming positively buoyant as fuel burns off, nor does it need to vent helium to land. However, it still maintains the capability to loiter for incredibly long periods in the sky as it needs to burn very little fuel to stay aloft. Reportedly, it is capable of five days when manned, and even longer durations if operated in an unmanned configuration. Using helium for lift instead of solely relying on engine thrust and wings means that it is much more fuel efficient than traditional fixed-wing airliners. The company’s own estimates suggest the Airlander 10 could slash emissions on short-haul air routes by up to 90%. The gentle take-off and landing characteristics also mean the vehicle doesn’t require traditional airport facilities, making it possible to operate more easily in remote areas, on grass, sand, or even water. Continue reading “Could Airships Make A Comeback With New Hybrid Designs?”

Clever Gas Mixer Gets Just The Right Blend For Homebrew Laser Tubes

[Lucas] over at Cranktown City on YouTube has been very busy lately, but despite current appearances, his latest project is not a welder. Rather, he built a very clever gas mixer for filling his homemade CO2 laser tubes, which only looks like a welding machine. (Video, embedded below.)

We’ve been following [Lucas] on his journey to build a laser cutter from scratch — really from scratch, as he built his own laser tube rather than rely on something off-the-shelf. Getting the right mix of gas to fill the tube has been a bit of a pain, though, since he was using a party balloon to collect carbon dioxide, helium, and nitrogen at measuring the diameter of the ballon after each addition to determine the volumetric ratio of each. His attempt at automating the process centers around a so-called AirShim, which is basically a flat inflatable bag made of sturdy material that’s used by contractors to pry, wedge, lift, and shim using air pressure.

[Lucas]’ first idea was to measure the volume of gas in the bag using displacement of water and some photosensors, but that proved both impractical and unnecessary. It turned out to be far easier to sense when the bag is filled with a simple microswitch; each filling yields a fixed volume of gas, making it easy to figure out how much of each gas has been dispensed. An Arduino controls the pump, which is a reclaimed fridge compressor, monitors the limit switch and controls the solenoid valves, and calculates the volume of gas dispensed.

Judging by the video below, the mixer works pretty well, and we’re impressed by its simplicity. We’d never seriously thought about building our own laser tube before, but seeing [Lucas] have at it makes it seem quite approachable. We’re looking forward to watching his laser project come together.

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Scratch-Built CO2 Laser Tube Kicks Off A Laser Cutter Build

When we see a CO2 laser cutter build around these parts, chances are pretty good that the focus will be on the mechatronics end, and that the actual laser will be purchased. So when we see a laser cutter project that starts with scratch-building the laser tube, we take notice.

[Cranktown City]’s build style is refreshingly informal, but there’s a lot going on with this build that’s worth looking at — although it’s perhaps best to ignore the sourcing of glass tubing by cutting the ends off of an old fluorescent tube; there’s no mention of what became of the mercury vapor or liquid therein, but we’ll just assume it was disposed of safely. We’ll further assume that stealing nitrogen for the lasing gas mix from car tires was just prank, but we did like the rough-and-ready volumetric method for estimating the gas mix.

The video below shows the whole process of building and testing the tube. Initial tests were disappointing, but with a lot of tweaking and the addition of a much bigger neon sign transformer to power the tube, the familiar bluish-purple plasma made an appearance. Further fiddling with the mirrors revealed the least little bit of laser output — nowhere near enough to start cutting, but certainly on the path to the ultimate goal of building a laser cutter.

We appreciate [Cranktown City]’s unique approach to his builds; you may recall his abuse-powered drill bit index that we recently covered. We’re interested to see where this laser build goes, and we’ll be sure to keep you posted.

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Hackaday Links: August 30, 2020

Tech history is rife with examples of bizarre product demos, but we’ve got to think that Elon Musk’s Neuralink demo this week will have to rank up there with the weirdest of them. Elon’s job here was to sell the proposition that having a quarter-sized plug removed from your skull by a surgical robot and having it plunge 1,024 tiny wires into your gray matter will be totally normal and something that all the cool kids will be doing someday. We watched the 14-minute supercut of the demo, which went on for considerably longer than that due to the realities of pig wrangling, and we remain unsold on the technology. Elon selling it as “a Fitbit in your skull, with tiny wires” probably didn’t help, nor did the somewhat terrifying appearance of the surgical robot needed to do the job. On the other hand, Gertrude the Bionic Pig seemed none the worse for her implant, which was reportedly wired to her snout and sending data wirelessly. The demonstration of reading joint positions directly from the brain was honestly pretty neat. If you want to dive deeper into Neuralink, check out Maya’s great article that separates fact from science fiction.

Jerry Carr, NASA astronaut and commander of the third and final crewed Skylab mission, passed away this week at the age of 88. Carr’s Skylab 4 mission was record-breaking in 1974, with the three astronauts living and working in the orbiting workshop for 84 days. The mission contributed a vast amount of information on space medicine and the human factors of long-duration spaceflight. Carr retired from NASA in 1977 and had a long career as an engineer and entrepreneur. It’s sad to lose yet another of the dwindling number of heroes remaining from NASA’s manned-flight heyday.

Speaking of spaceflight, the closest most of us DIYers can get to space is likely courtesy of a helium-filled balloon. If you’ve ever considered sending something — or someone — aloft, you’ll find this helium balloon calculator an invaluable tool. Just plug in the weight of your payload, select from a few common balloon sizes, and the calculator will tell you how many you need and how much gas it will take to fill them. It’s got a second section that tells you how many more balloons it’ll take to get to a certain altitude, should merely getting off the ground not be enough for you.

If 2020 has proven anything, it’s that time is, at best, a negotiable concept. Improbably, September is only a day away, after an August that somehow took forever to go by in the blink of an eye. With that in mind,  October is OSHWA’s Open Hardware Month, with this year’s theme being “Label and Certify”. We’re a little bit in love with the Open Hardware Facts generator, which takes your open-source hardware, software, and documentation license and generates a USDA “Nutrition Facts”-style label for your product. They’ve also added tools to make it easier to get OSHWA certification for your project.

And finally, what would it be like to pilot a giant exoskeleton? Like, a 9,000 pound (4,100 kg), quadrupedal all-terrain beast of a mech? Turns out you can (theoretically) find out for yourself courtesy of Furrion Exo-Bionics and their monster mech, dubbed Prosthesis. The machine has been in development for a long time, with the vision of turning mech racing into the next big thing in sports entertainment. Their Alpha Mech Pilot Training Program will allow mere mortals to learn how to pilot Prosthesis at the company’s proving ground in British Columbia. Details are sparse, so caveat emptor, but it sure looks like fun.

Portable MRI Machine Comes To The Patient

To say that the process of installing a magnetic resonance imager in a hospital is a complex task is a serious understatement. Once the approval of regulators is obtained, a process that could take years, architects and engineers have to figure out where the massive machine can be installed. An MRI suite requires a sizable electrical service to be installed, reinforced floors to handle the massive weight of the magnet, and special shielding in the walls and ceiling. And once the millions have been spent and the whole thing is up and running, there are ongoing safety concerns when working around a gigantic magnet that can suck ferromagnetic objects into it at any time.

MRI studies can reveal details of diseases and injuries that no other imaging modality can match, which justifies the massive capital investments hospitals make to obtain them. But what if MRI scanners could be miniaturized? Is there something inherent in the technology that makes them so massive and so expensive that many institutions are priced out of the market? Or has technology advanced far enough that a truly portable MRI?

It turns out that yes, an inexpensive MRI scanner is not only possible, but can be made portable enough to wheel into a patient care room. It’s not without compromise, but such a device could make a huge impact on diagnostic medicine and extend MRI technologies into places far beyond the traditional hospital setting.

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Kitty Litter And Broken Light Bulbs Power This Homebrew Gas Chromatograph

We’re always on the lookout for unexpected budget builds here at Hackaday, and stumbling across a low-cost, DIY version of an instrument that sells for tens of thousands of dollars is always a treat. And so when we saw a tip for a homebrew gas chromatograph in the tips line this morning, we jumped on it. (Video embedded below.)

For those who haven’t had the pleasure, gas chromatography is a chemical analytical method that’s capable of breaking a volatile sample up into its component parts. Like all chromatographic methods, it uses an immobile matrix to differentially retard the flow of a mobile phase containing the sample under study, such that measurement of the transit time through the system can be made and information about the physical properties of the sample inferred.

The gas chromatograph that [Chromatogiraffery] built uses a long stainless steel tube filled with finely ground bentonite clay, commonly known as kitty litter, as the immobile phase. A volatile sample is injected along with an inert carrier gas – helium from a party balloon tank, in this case – and transported along the kitty litter column by gas pressure. The sample interacts with the column as it moves along, with larger species held back while smaller ones speed along. Detection is performed with thermal conductivity cells that use old incandescent pilot lamps that have been cracked open to expose their filaments to the stream of gas; using a Wheatstone bridge and a differential amp, thermal differences between the pure carrier gas and the eluate from the column are read and plotted by an Arduino.

The homebrew GC works surprisingly well, and we can’t wait for [Chromatogiraffery] to put out more details of his build.

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