Frnisi DMC-100: A Clamp Meter Worth Cracking Open

May 4, 2025 by Heidi Ulrich 17 Comments

Not all clamp meters are the same, and this video shows just that. In a recent teardown by [Kerry Wong], the new Fnirsi DMC-100 proves that affordable doesn’t mean boring. This 10,000-count clamp meter strays from the classic rotary dial in favour of a fully button-based interface – a choice that’s got sparks flying in the comments. And yes, it even auto-resumes its last function after reboot, like it knows you’re busy frying other fish.

What sets this meter apart isn’t just its snappy interface or surprisingly nice gold-tipped probes. It’s the layered UX – a hackable interface where short- and long-presses unlock hidden menus, memory functions, and even a graphing mode. A proper “hold-my-beer” moment comes when you discover it can split-display voltage and current and calculate real-time power (albeit with a minor asterisk: apparent power only, no power factor). Despite a few quirks, like accidentally triggering the flashlight when squeezing the jaw, it holds up well in accuracy tests. Even at higher currents where budget meters usually wobble.

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A human hand is shown in the bottom right corner of the picture, holding one end of a pencil. A white, segmented, mechanical tentacle extends from the bottom left corner of the image and wraps around the other end of the pencil.

3D Printed Cable-Driven Mechanisms – Some Strings Attached

May 3, 2025 by Aaron Beckendorf 10 Comments

One of the most basic problems with robotic arms and similar systems is keeping the weight down, as more weight requires a more rigid frame and stronger actuators. Cable-driven systems are a classic solution, and a team of researchers from MIT and Zhejiang University recently shared some techniques for designing fully 3D printed cable-driven mechanisms.

The researchers developed a set of four primitive motion components: a bending component, a coil, screw-like, and a compressive component. These components can work together in series or parallel to make much more complicated structures. To demonstrate, the researchers designed a gripping tentacle, a bird’s claw, and a lizard-like walking robot, but much more complicated structures are certainly possible. Additionally, since the cable itself is printed, it can have extra features, such as a one-way ratcheting mechanism or bumps for haptic feedback.

These printed cables are the most novel aspect of the project, and required significant fine-tuning to work properly. To have an advantage over manually-assembled cable-driven systems, they needed to be print-in-place. This required special printer settings to avoid delamination between layers of the cable, cables sticking to other components, or cables getting stuck in the mechanism’s joints. After some experiments, the researchers found that nylon filament gives the best balance between cable strength and flexibility, while not adhering tightly to the PLA structure.

We’ve seen cable-driven systems here a few times before. If you’re interested in a deeper dive, we’ve covered that too.

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Testing A Cheap Bench Power Supply Sold On Amazon

May 3, 2025 by Maya Posch 19 Comments

We’ve all seen those cheap bench power supply units (PSUs) for sale online, promising specifications that would cost at least a hundred dollars or more if it were a name brand model. Just how much of a compromise are these (usually rebranded) PSUs, and should you trust them with your electronics? Recently [Denki Otaku] purchased a cheap unit off Amazon Japan for a closer look, and found it to be rather lacking.

Internals of the cheap bench PSU reviewed by Denki Otaku on YouTube.

Major compromises include the lack of an output power switch, no way to check the set current limit without shorting the output, very slow drop in output voltage while adjusting due to the lack of a discharge circuit, and other usability concerns. That’s when the electrical performance of the PSU got tested.

Right off the bat a major issue in this cheap switching mode PSU is clear, as it has 200 mV peak-to-peak noise on its output, meaning very little output filtering. The maximum power output rating was also far too optimistic, with a large voltage drop observed. Despite this, it generally worked well, and the internals – with a big aluminium plate as heatsink – look pretty clean with an interesting architecture.

The general advice is to get a bench PSU that has features like an output power button and an easy way to set the voltage and current limits. Also do not connect it to anything that cares about noise and ripple unless you know that it produces clean, filtered output voltages.

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LLM Ported To The C64, Kinda

May 3, 2025 by Lewin Day 8 Comments

“If there’s one thing the Commodore 64 is missing, it’s a large language model,” is a phrase nobody has uttered on this Earth. Yet, you could run one, if you so desired, thanks to [ytm] and the Llama2.c64 project!

[ytm] did the hard work of porting the Llama 2 model to the most popular computer ever made. Of course, as you might expect, the ancient 8-bit machine doesn’t really have the stones to run an LLM on its own. You will need one rather significant upgrade, in the form of 2 MB additional RAM via a C64 REU.

Now, don’t get ahead of things—this is no wide-ranging ChatGPT clone. It’s not going to do your homework, counsel you on your failed marriage, or solve the geopolitical crisis in your local region. Instead, you’re getting the 260 K tinystories model, which is a tad more limited. In [ytm]’s words… “Imagine prompting a 3-year-old child with the beginning of a story — they will continue it to the best of their vocabulary and abilities.”

It might not be supremely capable, but there’s something fun about seeing such a model talking back on an old-school C64 display. If you’ve been hacking away at your own C64 projects, don’t hesitate to let us know. We certainly can’t get enough of them!

Thanks to [ytm] for the tip!

Tablet Suspension System Avoids Fatigue At Bedtime

May 3, 2025 by Seth Mabbott 12 Comments

You know how it is. You’re all cozy in bed but not quite ready to doze off. You’re reading Hackaday (Hackaday is your go-to bedtime reading material, right?) or you’re binge-watching your latest reality TV obsession on your tablet. You feel the tablet growing heavier and heavier as your arms fatigue from holding it inches above your face. You consider the embarrassment you’ll endure from explaining how you injured your nose as the danger of dropping the tablet gradually increases. The struggle is real.

[Will Dana] has been engineering his way out of this predicament for a few years now, and with the recent upgrade to his iPad suspension system he is maximizing his laziness, but not without putting in a fair amount of hard work first.

The first iteration of the device worked on a manual pulley system whereby an iPad was suspended from the ceiling over his bed on three cords. Pulling on a cord beside the bed would raise the bracket used for holding the iPad out of the way while not in use. This new iteration takes that pesky cord pulling out of the user’s hands, replacing it with a motorized winch. A spot of dark ink on one of the cords in combination with a light sensor helps to calibrate the system so that the ESP32 which controls it always knows the proper limits of operation.

Of course, if, like [Will], you’re using an ESP32, and your room is already fully controlled by a voice interface, you may as well integrate the two. After all, there is no sense in wasting precious energy by pressing buttons. Utter a simple command to Alexa once you’re tucked in, and it’s time for hands-free entertainment.

We’ve covered several of [Will]’s previous creations, such as his Motorized Relay Computer and Harry Potter-inspired Sorting Hat.

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Hacking Different Sized Nozzles For AnyCubic Printers

May 3, 2025 by Lewin Day 11 Comments

If you’ve got a popular 3D printer that has been on the market a good long while, you can probably get any old nozzles you want right off the shelf. If you happen to have an AnyCubic printer, though, you might find it a bit tougher. [Startup Chuck] wanted some specific sized nozzles for his rig, so set about whipping up a solution himself.

[Chuck]’s first experiments were simple enough. He wanted larger nozzles than those on sale, so he did the obvious. He took existing 0.4 mm nozzles and drilled them out with carbide PCB drills to make 0.6 mm and 0.8 mm nozzles. It’s pretty straightforward stuff, and it was a useful hack to really make the best use of the large print area on the AnyCubic Kobra 3.

But what about going the other way? [Chuck] figured out a solution for that, too. He started by punching out the 0.4 mm insert in an existing nozzle. He then figured out how to drive 0.2 mm nozzles from another printer into the nozzle body so he had a viable 0.2 mm nozzle that suited his AnyCubic machine.

The result? [Chuck] can now print tiny little things on his big AnyCubic printer without having to wait for the OEM to come out with the right nozzles. If you want to learn more about nozzles, we can help you there, too.

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Knowing What’s Possible

May 3, 2025 by Elliot Williams 13 Comments

Dan Maloney and I were talking on the podcast about his memories of the old electronics magazines, and how they had some gonzo projects in them. One, a DIY picture phone from the 1980s, was a monster build of a hundred ICs that also required you to own a TV camera. At that time, the idea of being able to see someone while talking to them on the phone was pure science fiction, and here was a version of that which you could build yourself.

Still, we have to wonder how many of these were ever built. The project itself was difficult and expensive, but you actually have to multiply that by two if you want to talk with someone else. And then you have to turn your respective living rooms into TV studios. It wasn’t the most practical of projects.

But amazing projects did something in the old magazines that we take a little bit for granted today: they showed what was possible. And if you want to create something new, you’re not necessarily going to know how to do it, but just the idea that it’s possible at all is often enough to give a motivated hacker the drive to make it real. As skateboard hero Rodney Mullen put it, “the biggest obstacle to creativity is breaking through the barrier of disbelief”.

In the skating world, it’s seeing someone else do a trick in a video that lets you know that it’s possible, and then you can make it your own. In our world, in prehistoric times, it was these electronics magazines that showed you what was possible. In the present, it’s all over the Internet, and all over Hackaday. So when you see someone’s amazing project, even if you aren’t necessarily into it, or maybe don’t even fully understand it, your horizons of what’s possible are nonetheless expanded, and that helps us all be more creative.

Keep on pushing!