If You Want An Expensive Chair Just Print Your Own

July 10, 2024 by 20 Comments

The Magis Spun chair is a weird piece. It’s basically a kind of seat with a round conical base that stops it from sitting still in one place. Instead, it rolls and pivots around when you sit on it, which is apparently quite fun. They’re expensive though, which gave [Morley Kert] a neat idea. Why not 3D print one instead?

Obviously 3D printing a sofa wouldn’t be straightforward, but the Magis Spun is pretty much just a hunk of plastic anyway. The real thing is made with rotational molding. [Morley] suspected he could make one for less than the retail price with 3D printing.

With no leads on a big printer, he decided to go with a segmented design. He whipped up his basic 3D model through screenshots from the manufacturer’s website and measurements of a display model in a store. After print farming the production, the assembly task was the next big challenge. If you’re interested in doing big prints with small printers, this video is a great way to explore the perils of this idea.

Ultimately, if you want to print one of these yourself, it’s a big undertaking. It took 30-50 print days, or around 5 days spread across 15 printers at Slant 3D’s print farm. It used around $300-400 of material at retail prices, plus some extra for the epoxy and foam used to assemble it.

The finished product was killer, though, even if it looks a little rough around the edges. It rolls and pivots just like the real thing.

We don’t feature a lot of chair hacks on Hackaday, but we do feature some! Video after the break.

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FLOSS Weekly Episode 791: It’s All About Me!

July 10, 2024 by 1 Comment

This week David Ruggles chats with Jonathan Bennett about his origin story! What early core memory does Jonathan pin his lifelong computer hobby on? And how was a tense meeting instrumental to Jonathan’s life outlook? And how did Jonathan manage to score a squashable brain toy from an equipment manufacturer? Watch the whole show to find out!

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Supercon 2023: Why More Hackers Should Earn Their Wings

July 10, 2024 by 14 Comments

Hacking has taken on many different meanings over the years, but if you’re here reading these words, we’ll assume your definition is pretty close to ours. To hack is to explore and learn, to find new and (hopefully) better ways of doing things. Or at least, that’s part of it. The other part is to then take what you learned and share it with others. Do that enough, and soon you’ll find yourself part of a community of like-minded individuals — which is where things really start getting interesting.

Here at Hackaday the objects of our attention are, with the occasional exception, electronic devices of some sort or another. Perhaps an old piece of gear that needs a modern brain transplant, or a misbehaving consumer gadget that could benefit from the addition of an open source firmware. But just as there are different ways to interpret the act of hacking, there’s plenty of wiggle room when it comes to what you can hack on.

In his talk during the 2023 Hackaday Supercon, Tom Mloduchowski makes the case that more hackers should be getting involved with aviation. No, we’re not talking about flying drones, though he does cover that during the presentation. This is the real deal. Whether you want to take a quick joyride in a small plane, become a professional pilot, or even build and operate your own experimental aircraft, this talk covers it all.

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Bringing The 555 Mini-Notebook To Video

July 10, 2024 by 17 Comments

Like many of us [AnotherMaker] is a fan of the classic Forrest Mims electronics books, specifically, the Engineer’s Mini-Notebook series. They were great sources of inspiration, but at the time, he couldn’t afford to actually build most of the circuits described. Now as an adult, he decided to go through the 555 Timer IC Circuits Mini-Notebook, full of example circuits and explanations, all in Mims’ trademark handwritten style, and build all the circuits for real. And so, a series of YouTube videos are currently being released going over every circuit, how it works, and looking at waveforms on an oscilloscope!

So, PCBs were designed, each containing four of the circuits from the book. With the Mims circuit diagram on one side of the screen and the PCB on the other, [AnotherMaker] goes into a good amount of detail explaining how each circuit works, referring to the schematic and oscilloscope as needed. Each part in the series focuses on the next circuits in order, and eventually the whole series will cover every single circuit in the book.

It’s a great series of videos for anyone learning electronics, especially those who would like to learn about one of the most produced integrated circuits of all time! It’s also an excellent way to bring a fresh perspective to this classic book, while simultaneously bringing the content to a wider audience via online video.

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Model Rocket Nails Vertical Landing After Three-Year Effort

July 10, 2024 by 30 Comments

Model rocketry has always taken cues from what’s happening in the world of full-scale rockets, with amateur rocketeers doing their best to incorporate the technologies and methods into their creations. That’s not always an easy proposition, though, as this three-year effort to nail a SpaceX-style vertical landing aptly shows.

First of all, hats off to high schooler [Aryan Kapoor] from JRD Propulsion for his tenacity with this project. He started in 2021 with none of the basic skills needed to pull off something like this, but it seems like he quickly learned the ropes. His development program was comprehensive, with static test vehicles, a low-altitude hopper, and extensive testing of the key technology: thrust-vector control. His rocket uses two solid-propellant motors stacked on top of each other, one for ascent and one for descent and landing. They both live in a 3D printed gimbal mount with two servos that give the stack plus and minus seven degrees of thrust vectoring in two dimensions, which is controlled by a custom flight computer with a barometric altimeter and an inertial measurement unit. The landing gear is also clever, using rubber bands to absorb landing forces and syringes as dampers.

The video below shows the first successful test flight and landing. Being a low-altitude flight, everything happens very quickly, which probably made programming a challenge. It looked like the landing engine wasn’t going to fire as the rocket came down significantly off-plumb, but when it finally did light up the rocket straightened and nailed the landing. [Aryan] explains the major bump after the first touchdown as caused by the ascent engine failing to eject; the landing gear and the flight controller handled the extra landing mass with aplomb.

All in all, very nice work from [Aryan], and we’re keen to see this one progress.

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Build Your Own 16 MB 30-Pin SIMMs For Vintage PCs

July 9, 2024 by 28 Comments

Today’s memory sticks have hundreds of pins and many gigabytes of RAM on board. Decades ago, though, the humble 30-pin SIMM was the state of the art where memory was concerned. If you’ve got vintage gear, you can try and hunt down old RAM, or you can copy [Bits und Bolts] and make your own.

Previously, [Bits und Bolts] built a 4 MB SIMM, but he’s now ramped up to building 16 MB RAM sticks — the largest size supported by the 30-pin standard. That’s a ton compared to most 30-pin sticks from the 1980s, which topped out at a feeble 1 MB.

We get to see four of his 16 MB sticks installed in a 386 motherboard, set up to operate in the appropriate Fast Page Mode. He was able to get the system operating with 64 MB of RAM, an amount still considered acceptable in the early Pentium 3 era. Hilariously, memtest took a full ten hours to complete a single pass with this configuration. [Bits and Bolts] also tried to push the motherboard further, but wasn’t able to get it to POST with over 64 MB of RAM.

As [Bits und Bolts] demonstrates, if you can read a schematic and design a PCB, it’s not that hard to design RAM sticks for many vintage computers. We’ve seen some other RAM hacks in this vein before, too.

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Building A Cassette Deck Controller To Save A Locked Out Car Stereo

July 9, 2024 by 26 Comments

Cars have had DRM-like measures for longer than you might think. Go back to the 1990s, and coded cassette decks were a common way to stop thieves being able to use stolen stereos. Sadly, they became useless if you ever lost the code. [Simon] had found a deck in great condition that was locked out, so he set about building his own controller for it. 

The build relies on the cassette transport of a car stereo and a VFD display, but everything else was laced together by Simon. It’s a play-only setup, with no record, seeing as its based on an automotive unit. [Simon]’s write up explains how he reverse engineered the transport, figuring out how the motors and position sensors worked to control the playback of a cassette.

[Simon] used an Atmega microcontroller as the brains of the operation, which reads the buttons of the original deck via an ADC pin to save I/O for other tasks. The chip also drives the VFD display for user feedback, and handles auto reverse too. The latter is thanks to the transport’s inbuilt light barriers, which detect the tape’s current status. On the audio side, [Simon] whipped up his own head amplifier to process the signal from the tape head itself.

Fundamentally, it’s a basic build, but it does work. We’ve seen other DIY tape decks before, too. There’s something about this format that simply refuses to die. The fans just won’t let Compact Cassette go down without a fight. Video after the break.

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