Multi-Stage Ion Thruster Holds Exciting Promise

September 19, 2022 by Tom Nardi 56 Comments

Anyone who’s looked into high-voltage experiments is likely familiar with ion lifters — spindly contraptions made of wire and aluminum foil that are able to float above the workbench on a column of ionized air. It’s an impressive trick that’s been around since the 1950s, but the concept has yet to show any practical application as the thrust generated isn’t nearly enough to lift a more substantial vehicle.

It’s a bit early to suggest that [Jay Bowles] of Plasma Channel has finally found the solution to this fundamental shortcoming of electrostatic propulsion, but his recently completed multi-stage ion thruster certainly represents something of a generational leap for the technology. By combining multiple pairs of electrodes and experimentally determining the optimal values for their spacing and operational voltage, he’s been able to achieve a sustained exhaust velocity of 2.3 meters per second.

Dry ice was used to visualize airflow through the thruster.

While most ion thrusters are lucky to get a piece of paper fluttering for their trouble, [Jay] demonstrates his creation blowing out candles at a distance of a meter or more. But perhaps the most impressive quality of this build is the sound — unlike most of the experimental ion thrusters we’ve seen, the air flowing through this contraption actually makes an audible roaring sound. When the 45 kilovolt supply voltage kicks in it sounds like a hair drier, except here there’s no moving parts involved.

In addition to providing graphs that show how air velocity was impacted by input voltage and the number and spacing of the electrode pairs, [Jay] also pops the thruster on a scale to show that there is indeed a measurable thrust being produced. Admittedly the 22 grams of thrust being generated isn’t much compared to the contraption’s own mass of 490 grams, but in the world of electrostatic propulsion, those are pretty impressive numbers.

[Jay] says he has some improvements in mind that he believes will significantly improve the device’s performance as he works towards his ultimate goal of actually flying an ion-propelled aircraft. We saw MIT do it back in 2018, and it would be great to see an individual experimenter pull off a similar feat. Obviously, there’s still a long way to go before this thing takes to the skies, but if anyone can pull it off, it’s [Jay Bowles].

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Building Bridges In This Week’s Hack Chat

September 16, 2022 by Tom Nardi 5 Comments

In the electronics world, even for the hobbyists, things have only gotten smaller over the years. We went from through-hole components to surface mount, and now we’re at the point where the experienced DIYers are coming around to the idea of using ball grid array (BGA) components in their designs. We’d wonder what things are going to look like in another couple decades, but frankly, it gives us the heebie-jeebies.

So while we’re pretty well versed these days in the hows and whys of tiny things, we see comparatively little large-scale engineering projects. Which is why we were excited to have Andy Oliver stop by this week for the Heavy Engineering Hack Chat. His day job sees him designing and inspecting the control systems for movable bridges — or what many would colloquially refer to as drawbridges.

Now you might think there’s not a lot of demand for this particular skill set, but we’re willing to bet there’s a lot more of these bridges out there than you realized. Andy kicked things off with the revelation that just between the states of Florida and Louisiana, there are about 200 movable bridges of various sizes. On a larger scale, he points out that BridgeHunter.com lists an incredible 3,166 movable bridges in their database, though admittedly many of those are historical and no longer standing. (There really is a site for everything!)

There’s also a huge incentive to keep the existing bridges functioning for as long as possible — building a new one these days could cost hundreds of millions of dollars. Instead, repairs and upgrades are the name of the game. Andy says that if it’s properly maintained, you should get about a century out of a good bridge.

It will probably come as little surprise to find that keeping things as simple as possible is key to making sure a movable bridge can withstand the test of time. While we might imagine that all sorts of high-tech automation systems are at work, and they probably would be if any of us were in charge, Andy says that most of the time it’s old school relay logic.

Even controlling the speed of motors is often down to using beefy relays to switch some additional resistance into the circuit. But when reliability and ease of repair are top priorities, who’s to argue against a classic? Andy recalled a time when a government client made it clear that the only tool you should need to maintain a particular bridge’s control system was a hammer.

Of course, when moving around a million pounds of steel, there’s more than just electrical considerations at play. You’ve also got to take into account things like wind forces on the bridge, specifically that your gears and motors can handle the extra load without tearing themselves apart. The bridge also needs an emergency stop system that can arrest movement at a moment’s notice, but not damage anything in the process.

A lot of fascinating details about these motorized behemoths were covered in the Chat, so we’d invite anyone who’s ever watched a bridge slowly reconfigure itself to peruse through the full transcript. Special thanks to Andy Oliver for stopping by and sharing some of the details about his unique career with the community, and remember that if you’ve got your own engineering stories to tell, we’d love to hear them.

The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Hackaday Podcast 185: A 2022 Rotary Phone, How AI Imagines Zepplin, Are We Alone In The Universe

September 16, 2022 by Tom Nardi 3 Comments

This week, Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi start off by talking about the chip shortage…but not how you think. With a list that supposedly breaks down all of the electronic components that the Russian military are desperate to get their hands on, we can see hackers aren’t the only ones scrounging for parts. If you thought getting components was tricky already, imagine if most of the world decided to put sanctions on you.

We’ll also talk about kid-friendly DIY stereoscopic displays, the return of the rotary cellphone, and using heat to seal up 3D printed parts for vacuum applications. Join us as we marvel over the use of rubbery swag wristbands as tank treads, and ponder an array of AI-created nightmares that are supposed to represent the Hackaday writing crew. Finally we’ll talk about two iconic legacies: that of the 3.5 inch floppy disk, and astrophysicist Frank Drake.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download, and burn it to your own CD!

Continue reading “Hackaday Podcast 185: A 2022 Rotary Phone, How AI Imagines Zepplin, Are We Alone In The Universe” →

2022 Cyberdeck Contest: RPG Character Tracker

September 14, 2022 by Tom Nardi 7 Comments

While it would be a mistake to think there are any firm rules for what constitutes a cyberdeck, we can at least identify some common traits that would seem to give us a baseline description. For example, most deck builds we’ve seen have been fully-functional Linux computers, more often than not powered by some Raspberry Pi variant. But that doesn’t mean there isn’t room in the community for less computational powerful decks, or builds that are so bespoke that they can only perform a few selected tasks.

As a perfect example, take a look at the RPG Character Tracker from [Melissa Matos]. You won’t find a Raspberry Pi here, nor a full operating system. Instead, we’ve got a M5Stack Core2 and an I2C CardKB Mini Keyboard wrapped up in a foldable frame made from Erector Set pieces. Add in a little LED lighting for that cyberpunk feel, and the stage is set.

So what does this diminutive build do? Well, apparently nothing right now. [Melissa] just got the hardware together and has only recently started aligning all the 1s and 0s to do her bidding. But what it’s supposed to do is clear enough: it’s intended to be an electronic companion to complex RPG tabletop games to help with things such as character creation. Sounds like it will also have a “roll dice” mode that will save you the trouble of having to crawl under the table when one of your D20s goes rogue.

While such a device could be useful for many different games, it should come as no surprise to hear that [Melissa] is currently targeting the cyberpunk Shadowrun.

Although we were particularly taken with the online tool that let you generate 3D printed organizers for all your tabletop gaming needs, we’d definitely rather have digital companions like this which would make those plastic baggies full of parts obsolete.

With A Little Heat, Printed Parts Handle Vacuum Duty

September 13, 2022 by Tom Nardi 40 Comments

We don’t have to tell the average Hackaday reader that desktop 3D printing has been transformative for our community, but what might not be as obvious is the impact the technology has had on the scientific community. As explained in Thermal Post-Processing of 3D Printed Polypropylene Parts for
Vacuum Systems by [Pierce Mayville], [Aliaksei Petsiuk], and [Joshua Pearce], the use of printed plastic parts, especially when based on open source designs, can lead to huge cost reductions in the production of scientific hardware.

More specifically, the authors wanted to examine the use of 3D printing components to be used in a vacuum. Parts produced with filament-based printers tend to be porous, and as such, are not suitable for fittings or adapters which need to be pumped down to below one atmosphere. The paper goes on to explain that there are coatings that can be used to seal the printed parts, but that they can outgas at negative pressures.

The solution proposed by the team is exceptionally simple: after printing their desired parts in polypropylene on a Lulzbot Taz 6, they simply hit them with a standard consumer heat gun. With the temperature set at ~400 °C, it took a little under a minute for the surface of take on a glossy appearance — the result reminds us of an ABS print smoothed with acetone vapor.

As the part is heated, the surface texture visibly changes. The smoothed parts performed far better in vacuum testing.

In addition to the heat treatment, the team also experimented with increasing degrees of infill overlap in the slicer settings. The end result is that parts printed with a high overlap and then heat treated were able to reliably handle pressures as low as 0.4 mTorr. While the paper admits that manually cooking your printed parts with a heat gun isn’t exactly the ideal solution for producing vacuum-capable components, it’s certainly a promising start and deserves further study.

Blue Origin Loses Rocket, Gains Abort System Test

September 12, 2022 by Tom Nardi 15 Comments

Even if you’re just making a brief hop over the Kármán line to gain a few minutes of weightlessness, getting to space is hard. Just in case any of their engineers were getting complacent, Blue Origin just got a big reminder of that fact this afternoon with the destruction of their New Shepard 3 (NS3) rocket during a suborbital research flight.

But while the rocket itself was lost, the New Shepard’s automated abort systems were able to push the capsule H. G. Wells away from the fireball, saving the dozens of scientific experiments which had been loaded onto the un-crewed vehicle. While there’s been no public word yet on the condition of these experiments, it’s reasonable to assume that at least some portion of them can be re-flown in the future — a fact that will likely come as a great relief to the researchers who designed them. It will be interesting to see who picks up the tab for the do-over flight; while launch insurance is a must-have for billion dollar satellites, it seems unlikely these small suborbital experiments would have been covered under a similar policy.

A spurt of flame can be seen in the otherwise invisible exhaust moments before engine failure.

We’re also still in the dark about what caused the in-flight breakup of NS3, other than the fact that the engine was clearly sputtering in the seconds before it blew apart. This could be a sign that the engine’s nominal fuel-to-oxidizer ratio was faltering, or perhaps even indicative of foreign debris becoming dislodged and burning in the combustion chamber. But really, without official word from Blue Origin, it’s impossible to say what happened.

This is especially true when you consider that we’re talking about a vehicle that’s pushing the envelope to begin with. Remember, the New Shepard is a reusable booster, and NS3 is specifically a veteran of eight flights — with all but one of them taking the booster above the 100 kilometer altitude, which is generally accepted to be the boundary of space.

For those worried that celebrities and assorted millionaires will no longer have access to space, fear not. Blue Origin’s crewed flights have flown exclusively on the newer NS4 and its associated capsule First Step. This does however mean that Blue Origin no longer has a spare booster on which to fly commercial payloads, potentially putting into jeopardy any semblance of scientific value the program may have had.

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The Philly Maker Faire Is Back And Wants Your Hacks

September 12, 2022 by Tom Nardi 4 Comments

After two years of waiting out the COVID-19 pandemic, the Philadelphia Maker Faire is officially back for 2022. The one-day event will take place on Saturday, the 15th of October, from 10:00 am to 5:00 pm at the Independence Seaport Museum.

We don’t have a schedule or full list of what will be on display this far out, but given what we saw during our 2019 visit, we’re confident you’ll get your tickets worth. While we keenly felt the loss of the flagship Maker Faires in California and New York, we can take some solace in the fact that their absence has given these smaller Faires a chance to move in and grow in ways that might not have been possible before.

For those looking to take an active role in what’s often been called the “Greatest Show & Tell on Earth”, organizers will be accepting proposals until September 15th for individuals, groups, and companies that want to share their creations with attendees. Participation is free, so long as you aren’t trying to sell anything, and offers a fantastic way to show off those pandemic projects. That said, proposals aren’t limited to just hardware projects — artwork, live performances, and workshops will also be considered. Basically, if it’s something the STEAM crowd would be interested in checking out, consider it fair game.

If you can spare some time after seeing everything that will be on display at the Maker Faire, the Independence Seaport Museum itself sounds like a pretty fascinating place to check out. Beyond the exhibits and collection of maritime artifacts, the Seaport also offers the chance to take tours aboard a pair of unique vessels: the USS Olympia saw service in the Spanish–American and First World Wars, and USS Becuna is one of only eight surviving WWII Balao-class submarines currently available for public viewing.

Planning on attending the 2022 Philadelphia Maker Faire? Maybe even presenting? Let us know in the comments. Who knows, you might just run into a Hackaday writer in the wild and score yourself some coveted Wrencher stickers.