Physics Of Lightning Hack Chat

March 29, 2021 by Dan Maloney 2 Comments

Join us on Wednesday, March 31 at noon Pacific for the Physics of Lightning Hack Chat with Greg Leyh!

Of all the things that were around to terrify our ancestors, lightning must have been right up there on the list. Sure, the savannahs were teeming with things that wanted to make lunch out of you, but to see a streak of searing blue-white light emerge from a cloud to smite a tree out of existence must have been a source of dread to everyone. Even now, knowing much more about how lightning happens and how to protect ourselves from it, it’s still pretty scary stuff to be around.

But for as much as we know about lightning, there are plenty of unanswered questions about its nature. To get to the bottom of this, Greg Leyh wants to build a lightning machine of gargantuan proportions: a pair of 120 foot (36 m) tall Tesla towers. Each 10-story tower will generate 8.8 million volts and recreate the conditions inside storm clouds. It’s an ambitious goal, but Greg and his team at Lightning on Demand have already built and demonstrated a 1/3-scale prototype Tesla tower, which is impressively powerful in its own right.

As you can imagine, there are a ton of engineering details that have to be addressed to make a Tesla tower work, not to mention the fascinating physics going on inside a machine like this. Greg will stop by the Hack Chat to answer our questions about the physics of lightning, as well as the engineering needed to harness these forces and call the lightning down from the sky.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 31 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
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Wet Country Wireless; How The British Weather Killed A Billion Pound Tech Company

March 29, 2021 by Jenny List 51 Comments

A dingy and cold early February in a small British town during a pandemic lockdown is not the nicest time and place to take your exercise, but for me it has revived a forgotten memory and an interesting tale of a technology that promised a lot but delivered little. Walking through an early-1990s housing development that sprawled across the side of a hill, I noticed a couple of houses with odd antennas. Alongside the usual UHF Yagis for TV reception were small encapsulated microwave arrays about the size of a biscuit tin. Any unusual antenna piques my interest but in this case, though they are certainly unusual, I knew immediately what they were. What’s more, a much younger me really wanted one, and only didn’t sign up because their service wasn’t available where I lived.

All The Promise…

Ionica was a product of Cambridge University’s enterprise incubator, formed at the start of the 1990s with the aim of being the first to provide an effective alternative to the monopolistic British Telecom in the local loop. Which is to say that in the UK at the time the only way to get a home telephone line was to go through BT because they owned all the telephone wires, and it was Ionica’s plan to change all that by supplying home telephone services via microwave links.

Their offering would be cheaper than BT’s at the socket because no cable infrastructure would be required, and they would aim to beat the monopoly on call costs too. For a few years in the mid 1990s they were the darling of the UK tech investment world, with a cutting edge prestige office building just outside Cambridge, and TV adverts to garner interest in their product. The service launched in a few British towns and cities, and then almost overnight they found themselves in financial trouble and were gone. After their demise at the end of 1998 the service was continued for a short while, but by the end of the decade it was all over. Just what exactly happened?

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Hackaday Links: March 28, 2021

March 28, 2021 by Dan Maloney 17 Comments

If you thought the global shortage of computer chips couldn’t get any worse, apparently you weren’t counting on 2021 looking back at 2020 and saying, “Hold my beer.” As if an impacted world waterway and fab fires weren’t enough to squeeze supply chains, now we learn that water restrictions could potentially impact chip production in Taiwan. The subtropical island usually counts on three or four typhoons a year to replenish its reservoirs, but 2020 saw no major typhoons in the region. This has plunged Taiwan into its worst drought since the mid-1960s, with water-use restrictions being enacted. These include a 15% reduction of supply to industrial users as well as shutting off the water entirely to non-industrial users for up to two days a week. So far, the restrictions haven’t directly impacted chip and display manufacturers, mostly because their fabs are located outside the drought zone. But for an industry where a single fab can use millions of gallons of water a day, it’s clearly time to start considering what happens if the drought worsens.

Speaking of the confluence of climate and technology, everyone problem remembers the disastrous Texas cold snap from last month, especially those who had to endure the wrath of the unusually brutal conditions in person. One such victim of the storm is Grady, everyone’s favorite YouTube civil engineer, who recently released a very good post-mortem on the engineering causes for the massive blackouts experienced after the cold snap. In the immediate aftermath of the event, we found it difficult to get anything approaching in-depth coverage on its engineering aspects — our coverage excepted, naturally — as so much of what we found was laden with political baggage. Grady does a commendable job of sticking to the facts as he goes over the engineering roots of the disaster and unpacks all the complexity of the infrastructure failures we witnessed. We really enjoyed his insights, and we wish him and all our friends in Texas the best of luck as they recover.

If you’re into the demoscene, chances are pretty good that you already know about the upcoming Revision 2021, the year’s big demoscene party. Like last year’s Revision, this will be a virtual gathering, but it seems like we’re all getting pretty used to that by now. The event is next weekend, so if you’ve got a cool demo, head over and register. Virtual or not, the bar was set pretty high last year, so there should be some interesting demos that come out of this year’s party.

Many of us suffer from the “good enough, move on” mode of project management, leaving our benches littered with breadboarded circuits that got far enough along to ~~bore the hell out of us~~ make a minimally useful contribution to the overall build. That’s why we love it when we get the chance to follow up on a build that has broken from that mode and progressed past the point where it originally caught our attention. A great example is Frank Olsen’s all-wood ribbon microphone. Of course, with magnets and an aluminum foil ribbon element needed, it wasn’t 100% wood, but it still was an interesting build when we first spied it, if a bit incomplete looking. Frank has fixed that in grand style by continuing the wood-construction theme that completes this all-wood replica of the iconic RCA Model 44 microphone. It looks fabulous and sounds fantastic; we can’t help but wonder how many times Frank glued his fingers together with all that CA adhesive, though.

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Putting Your Time In

March 27, 2021 by Elliot Williams 28 Comments

I was absolutely struck by a hack this week — [Adam Bäckström]’s amazing robot arm built with modified hobby servos. Basically, he’s taken apart and re-built some affordable off-the-shelf servo motors, and like the 6-Million-Dollar Man, he’s rebuilt them better, stronger, faster. OK, and smoother. We have the technology.

The results are undeniably fantastic, and enable the experienced hacker to get champagne robot motion control on a grape-juice budget by employing some heavy control theory, and redundant sensors to overcome geartrain backlash, which is the devil of cheap servos. But this didn’t come out of nowhere. In his writeup, [Adam] starts off with “You could say this project started when I ordered six endless servos in middle school, more than 15 years ago.” And it shows.

Go check out this video of his first version of the modified servos, from a six-axis arm he built in 2009(!). He’s built in analog position sensors in the motors, which lets him control the speed and makes it work better than any other hobby servo arm you’ve ever seen, but there’s still visible backlash in the gears. A mere twelve years later, he’s got magnetic encoders on the output and a fast inner loop compensates for the backlash. The result is that the current arm moves faster and smoother, while retaining accuracy.

Twelve years. I assume that [Adam] has had some other projects on his plate as well, but that’s a long term project by any account. I’m stoked to see his work, not the least because it should help a lot of others who are ready to step up their desktop servo-arm projects. But the real take-home lesson here is that if you’ve got a tough problem that you’re hacking on, you don’t have to get it done this weekend. You don’t have to get it done next weekend either. Keep hammering on it as long as you need, but keep on hammering. When you get it done, the results will be all the better for the long, slow, brewing time. What’s the longest project that you’ve ever worked on?

Hackaday Podcast 111: 3D Graphics Are Ultrasonic, Lobotomizing Alexa, 3D-Printing Leaky Rockets, And Gaming The Font System

March 26, 2021 by Mike Szczys 4 Comments

Hackaday editors Mike Szczys and Elliot Williams curate a week of great hacks. Physical displays created in 3D space are a holy grail, and you can make one with 200 ultrasonic transducers, four FPGAs, and a lot math. Smart speakers have one heck of a microphone array in them, it’s yours for the hacking if you just roll your own firmware. Hobby servos can be awful, but this week we saw they can be made really great by cracking open the DC motor to add a simple DIY position sensor. And lasers are making their way into car headlights; we illuminate the situation in this episode.

Take a look at 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 (~60 MB)

Places to follow Hackaday podcasts:

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This Week In Security: XcodeSpy, Insecure SMS, And Partial Redactions

March 26, 2021 by Jonathan Bennett 25 Comments

There seems to be a new trend in malware, targeting developers and their development and build processes. The appeal is obvious: rather than working to build and market a malicious application, an attacker just needs to infect a development machine. The hapless infected developers can now do the hard work to spread the malicious payload.

The newest example is XcodeSpy, discovered by a researcher who chose to remain anonymous. It works by using the Xcode IDE’s Run Script function to, well, run a script that completely backdoors your computer. The instance was found in a repackaged open source project, TabBarInteraction, but they’re just innocent victims. It was simple enough for someone to insert a script in the build process, and distribute the new, doped package. It’s probably not the only one out there, so watch out for Run Scripts with obfuscated payloads.

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The $50 Ham: WSPR-ing Around The World

March 25, 2021 by Dan Maloney 18 Comments

Everybody has a bucket list, things to be accomplished before the day we eventually wake up on the wrong side of the grass. Many bucket-list items are far more aspirational than realistic; very few of us with “A trip to space” on our lists are going to live to see that fulfilled. And even the more realistic goals, like the trip to Antarctica that’s been on my list for ages, become less and less likely as your life circumstances change — my wife hates the cold.

Luckily, instead of going to Antarctica by myself — and really, what fun would that be? — I’ve recently been getting some of the satisfaction of world travel through amateur radio. The last installment of “The $50 Ham” highlighted weak-signal digital modes using WSJT-X; in that article, I mentioned a little about the Weak Signal Propagation Reporter, or WSPR. It’s that mode that let me test what’s possible with very low-power transmissions, and allowed me to virtually visit six continents including Antarctica and Sweden-by-way-of-Alaska.

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