Designing A Quality Camera Slider Can Be Remarkably Satisfying

May 15, 2024 by 7 Comments

Camera sliders are great creative tools, letting you get smooth controlled shots that can class up any production. [Anthony Kouttron] decided to build one for an engineering class, and he ended up mighty satisfied with what he and his team accomplished.

As an engineering class project, this wasn’t a build done on a whim. Instead, [Anthony] and his fellow students spent plenty of time hashing out what they needed this thing to do, and how it should be built. An Arduino was selected as the brains of the operation, as a capable and accessible microcontroller platform. Stepper motors and a toothed belt drive were used to move the slider in a controllable fashion. The slider’s control interface was an HD44780-based character LCD, along with a thumbstick and two pushbuttons. The slider relied on steel tubes for a frame, which was heavy, but cost-effective and easy to fabricate. Much of the parts were salvaged from legendary e-waste bins on the university grounds.

The final product was stout and practical. It may not have been light, but the steel frame and strong stepper motor meant the slider could easily handle even heavy DSLR cameras. That’s something that lighter builds can struggle with.

Ultimately, it was an excellent learning experience for [Anthony] and his team. As a bonus, he got some great timelapses out of it, too. Video after the break.

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How AI Large Language Models Work, Explained Without Math

May 15, 2024 by 24 Comments

Large Language Models (LLMs ) are everywhere, but how exactly do they work under the hood? [Miguel Grinberg] provides a great explanation of the inner workings of LLMs in simple (but not simplistic) terms that eschews the low-level mathematics of how they work in favor of laying bare what it is they do.

At their heart, LLMs are prediction machines that work on tokens (small groups of letters and punctuation) and are as a result capable of great feats of human-seeming communication. Most technical-minded people understand that LLMs have no idea what they are saying, and this peek at their inner workings will make that abundantly clear.

Be sure to also review an illustrated guide to how image-generating AIs work. And if a peek under the hood of LLMs left you hungry for more low-level details, check out our coverage of training a GPT-2 LLM using pure C code.

Hackaday Supercon 2024 Call For Participation: We Want You!

May 15, 2024 by 9 Comments

We’re tremendously excited to be able to announce that the Hackaday Supercon is on for 2024, and will be taking place November 1st through the 3rd in sunny Pasadena, California. As always, Supercon is all about you, the Hackaday community. So put on your thinking caps because we’d like to hear your proposals for talks and workshops! The Call for Speakers and Call for Workshops forms are online now, and you’ve got until July 9th to get yourself signed up.

Supercon is a fantastic event to geek out with your fellow hackers, and to share the inevitable ups and downs that accompany any serious project. Like last year, we’ll be featuring both longer and shorter talks, and hope to get a great mix of both first-time presenters and Hackaday luminaries.

Honestly, just the crowd that Supercon brings together is reason enough to attend, but then you throw in the talks, the badge-hacking, the food, and the miscellaneous shenanigans … it’s an event you really don’t want to miss. And as always, presenters get in for free, get their moment in the sun, and get warm vibes from the Hackaday audience. Get yourself signed up now!

Here’s The Norwegian Tape Deck Teardown You’ve Been Waiting For

May 15, 2024 by 37 Comments

“They just don’t build ’em like they used to” is a truer statement every year. Whether your vice is CRTs, film cameras, or tape decks, you’ll know that the very best gear simply isn’t manufactured anymore. Even the day-to-day stuff from 60 years ago is often a cut above a lot of today’s equipment. [Anthony Kouttron] shows us this with his teardown of a Tandberg TCD301 from many decades ago.

The Tandberg unit is beautifully finished in wood and metal, a style of construction that’s fairly rare these days. It’s got big, chunky controls, and a certain level of heft that is out of vogue in modern electronics. Heavy used to mean good — these days, it means old. That’s not to say it’s indestructible, though. It’s full of lots of old plastic pulleys and fasteners that have aged over the decades, so it’s a little fragile inside.

Still, [Anthony] gives us a great look at the aluminium chassis and buttons and the electromechanical parts inside. It’s a rats-nest design with lots of discrete components and wires flying between boards. You couldn’t economically produce this and sell it to anyone today, but this is how it was done so many years ago.

This non-functional unit ended up being little more than a salvage job, but we’re still glad that [Anthony] gave us a look inside. Still, if you long for more cassette-themed teardowns, we’ve got the goodness you’re looking for!

A Slice Of Simulation, Google Sheets Style

May 15, 2024 by 9 Comments

Have you ever tried to eat one jelly bean or one potato chip? It is nearly impossible. Some of us have the same problem with hardware projects. It all started when I wrote about the old bitslice chips people used to build computers before you could easily get a whole CPU on a chip. Bitslice is basically Lego blocks that build CPUs. I have always wanted to play with technology, so when I wrote that piece, I looked on eBay to see if I could find any leftovers from this 1970-era tech. It turns out that the chips are easy to find, but I found something even better. A mint condition AM2900 evaluation board. These aren’t easy to find, so the chances that you can try one out yourself are pretty low. But I’m going to fix that, virtually speaking.

This was just the second potato chip. Programming the board, as you can see in the video below, is tedious, with lots of binary switch-flipping. To simplify things, I took another potato chip — a Google Sheet that generates the binary from a quasi-assembly language. That should have been enough, but I had to take another chip from the bag. I extended the spreadsheet to actually emulate the system. It is a terrible hack, and Google Sheets’ performance for this sort of thing could be better. But it works.

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Introduction To MOSFET Switching Losses

May 15, 2024 by 17 Comments

Metal-oxide semiconductor field-effect transistors (MOSFETs) see common use in applications ranging from the very small (like CPU transistors) to very large (power) switching applications. Although its main advantage is its high power efficiency, MOSFETs are not ideal switches with a perfect on or off state. Understanding the three main sources of switching losses is crucial when designing with MOSFETs, with a recent All About Circuits article by [Robert Keim] providing a primer on the subject.

As it’s a primer, the subthreshold mode of MOSFET modes of operation is omitted, leaving the focus on the linear (ohmic) mode where the MOSFET’s drain-source is conducting, but with a resistance that’s determined by the gate voltage. In the saturated mode the drain-source resistance is relatively minor (though still relevant), but the turn-on time (RDS(on)) before this mode is reached is where major switching losses occur. Simply switching faster is not a solution, as driving the gate incurs its own losses, leaving the circuit designer to carefully balance the properties of the MOSFET.

For those interested in a more in-depth study of MOSFETs in e.g. power supplies, there are many articles on the subject, such as this article (PDF) from Texas Instruments.

Custom Polyurethane Belts Made Easy

May 15, 2024 by 13 Comments

If you need to make polyurethane belts in custom lengths, it’s not too hard. You just need to take lengths of flexible polyurethane filament, heat the ends, and join them together. In practice, it’s difficult to get it right by hand. That’s why [JBVCreative] built a 3D printed jig to make it easy. 

The jig consists of two printed sliders that mount on a pair of steel rods. Each slider has a screw-down clamp on top. The clamps are used to hold down each end of the polyurethane filament to be joined. Once installed in the jig, the ends of the filament can be heated with a soldering iron or other element. and then gently pushed together. The steel rods simply enable the filament to be constrained linearly so the ends don’t shift during the joining process.

The jig doesn’t produce perfect belts. There’s still a small seam at the join that is larger than the filament’s base diameter. A second jig for trimming the belt to size could be helpful in this regard. Still, it’s a super useful technique for making custom belts. This could be super useful to anyone needing to restore old cassette decks or similar mechanical hardware.

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