Day: March 16, 2020

Patterned Plywood Makes For Attractive Speakers

March 16, 2020 by 12 Comments

In the matter of audio, we’re well past the reign of the home hi-fi and the boombox. If you’re not listening on headphones or directly on your phone, you’ve got a brick-sized Bluetooth speaker pumping out the tunes. Still a fan of the old-school, [Amanda Ghassaei] built some bookshelf speakers with a hip aesthetic.

First, the speaker enclosures were designed in WinISD, a software package specifically made for the task. For given woofers and tweeters, it helps get the enclosure and port sizes in the correct range for good sound. Panels were then fabricated out of plywood to make the enclosures. The plywood was cut and reformed several times to make the panels, using the pattern from the multiple plies to create the zig-zag look. Audio wise, a class D amplifier takes in line-level signals, before pumping them out to a woofer and tweeter through a custom designed crossover network.

It’s a tidy build, and we’d love to experiment ourselves with the fancy patterned plywood technique. Getting your enclosure design right can make a big difference to sound quality, as we’ve seen before. Video after the break.

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Dissecting China-Sourced Vintage HP 1970s ICs: Genuine Or Not?

March 16, 2020 by 10 Comments

While repairing a real-time clock module for a 1970s HP computer that had been damaged by its leaky internal battery, [CuriousMarc] began to suspect that maybe the replacement clock chips which he had sourced from a seller in China were the reason why the module still wasn’t working after the repairs. This led him down the only obvious path: to decap and inspect both the failed original Ti chip and the replacement chip.

The IC in question is the Texas Instruments AC5948N (along with the AC5954N on other boards), which originally saw use in LED watches in the 1970s. HP used this IC in its RTC module, despite it never having been sold publicly. This makes it even more remarkable that a Chinese seller had the parts in stock. As some comments on the YouTube video mention, back then there wasn’t as much secrecy around designs, and it’s possible someone walked out of the factory with one of the masks for this chip.

Whether true or not, as the video (also included after the break) shows, both the original 1970s chip and the China-sourced one look identical. Are they original stock, or later produced from masks that made their way to Asia? We’ll probably never know for sure, but it does provide an exciting opportunity for folk who try to repair vintage equipment.

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A DIY Stun Gun You Probably Shouldn’t Build

March 16, 2020 by 36 Comments

In these troubled times, when a trip to the grocery store could turn into a brawl over toilet paper, you might be inclined to build yourself a low-cost electroshock weapon. Or at least, that’s what [Alex Zidros] did. We don’t necessarily recommend you follow in his footsteps, and we’re certainly not advocating testing it on a loved one. We just bring you this information, you have to decide what you do with it.

This is what peer pressure looks like.

So what does it take to build an improvised stun gun? Not a whole lot, it turns out. As you might have guessed, the star of the show is a high voltage transformer which supposedly puts out 400 kV. Just looking at it (and the price) we’re going to go out on a limb and say the performance specs are way overrated, but in this case that might actually be a good thing.

Beyond the transformer, there’s a simple 9 V battery holder and electrodes made from the prongs of a hacked up travel adapter. To deliver the lightning, [Alex] is using a pink arcade button. Just because you might be fighting for your life doesn’t mean you can’t have a little fun, right? Everything is packed into a simple 3D printed enclosure, but you could easily replace that with any suitably sized box. Something made out of wood might be a good idea, considering.

If you’d like to see another person shocked by a cobbled together high-voltage weapon, and potentially even learn something in the process, check out the “tutorial” video [Mehdi Sadaghdar] did back in 2014. We did mention you definitely shouldn’t do this at home, right?

Silo Launched Model Rocket Goes Thoomp

March 16, 2020 by 20 Comments

While rockets launched from silos are generally weapons of war, [Joe Barnard] of [BPS.Space] thought model rocketry could still do with a little more thoomp. So he built a functional tube launched model rocket.

Like [Joe]’s other rockets, it features a servo-actuated thrust vectoring system instead of fins for stabilization. The launcher consists of a 98 mm cardboard tube, with a pneumatic piston inside to eject the rocket out of the tube before it ignites its engine in mid-air. When everything works right, the rocket can be seen hanging motionlessly in the air for a split second before the motor kicks in.

The launcher also features a servo controlled hatch, which opens before the rocket is ejected and then closes as soon as the rocket is clear to protect the tube. The rocket itself is recovered using a parachute, and for giggles he added a tiny Tesla Roadster with its own parachute.

Projects as complex as this rarely work on the first attempt, and Thoomp was no exception. Getting the Signal flight computer to ignite the rocket motors at the correct instant proved challenging, and required some tuning on how the accelerometer inputs were used to recognize a launch event. The flight computer is also a very capable data logger, so every launch attempt, failed or successful, became a learning opportunity. Check out the second video after the break for a fascinating look at how all this data was analyzed.

[Joe]’s willingness to fail quickly and repeatedly as part of the learning process is a true display of the hacker spirit. We’ll definitely be keeping a close eye on his work.

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Where Do You Get Your Neutrons? Neutron Sources For Nuclear Fusion, Science, Medicine, And Industry

March 16, 2020 by 27 Comments

All of us probably know what neutrons are, or have at least heard of them back in physics class. Yet these little bundles of quarks are much more than just filler inside an atom’s nucleus. In addition to being an essential part of making matter as stable as it (usually) is, free neutrons can be used in a variety of manners.

From breaking atoms apart (nuclear fission), to changing the composition of atoms by adding neutrons (transmutation), to the use of neutrons in detecting water and inspecting materials, neutrons are an essential tool in the sciences, as well as in medicine and industrial applications. This has meant a lot of development toward the goal of better neutron sources. While nuclear fission is an efficient way to get lots of neutrons, for most applications a more compact and less complicated approach is used, some of which use nuclear fusion instead.

In this article we’ll be taking a look at the many applications of neutron sources, and these neutron sources themselves.

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Amateur Radio Homebrewing Hack Chat

March 16, 2020 by 12 Comments

Join us on Wednesday, March 18 at noon Pacific for the Amateur Radio Homebrewing Hack Chat with Charlie Morris!

For many hams, the most enticing part of amateur radio is homebrewing. There’s a certain cachet to holding a license that not only allows you to use the public airwaves, but to construct the means of doing so yourself. Homebrew radios range from simple designs with a few transistors and a couple of hand-wound coils to full-blown rigs that rival commercial transceivers in the capabilities and build quality — and sometimes even surpass them. Hams cook up every piece of gear from the antenna back, and in many ways, the homebrewers drive amateur radio technology and press the state of the art forward.

Taking the dive into homebrewing can be daunting, though. The mysteries of the RF world can be a barrier to entry, and having some guidance from someone who has “been there, done that” can be key to breaking through. New Zealand ham Charlie Morris (ZL2CTM) has been acting as one such guide for the adventurous homebrewer with his YouTube channel, where he presents his radio projects in clear, concise steps. He takes viewers through each step of his builds, detailing each module’s design and carefully walking through the selection of each component. He’s quick to say that his videos aren’t tutorials, but they do teach a lot about the homebrewer’s art, and you’ll come away from each with a new tip or trick that’s worth trying out in your homebrew designs.

Charlie will join us for the Hack Chat this Wednesday to discuss all things homebrewing. Stop by with your burning questions on DIY amateur radio, ask about some of Charlie’s previous projects, and get a glimpse of where he’s going next.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 18 at 12:00 PM Pacific time. If time zones have got you down, 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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