Author: Dan Maloney

3367 Articles

Linear Power Supply’s Current Limiter Is A Lesson In Simplicity

June 5, 2023 by 5 Comments

Here at Hackaday we really like to feature projects that push the limits of what’s possible, or ones that feature some new and exciting technology that nobody has ever seen before. So what’s so exciting about this single-voltage linear power supply? Honestly, nothing — until you start looking at its thermally compensated current limiting circuit.

This one is by [DiodeGoneWild], who you’ve really got to hand it to in terms of both the empirical effort he went through to optimize the circuit, as well as the quality of his explanation. The basic circuit is dead simple: a transformer, a full-wave rectifier, an LD1085 adjustable regulator — a low-dropout version of the venerable LM317 — and associated filter caps and trimmer pot to adjust the output between 2.2 and 5.5 volts.

The current limiting circuit, though, is where things get interesting. Rather than use an op-amp, [DiodeGoneWild] chose a simple discrete transistor current-sense circuit. To make it less susceptible to thermal drift, he experimented with multiple configurations of resistors and Schottky diodes over a wide range of temperatures, from deep-freeze cold to hair-dryer-in-a-box hot. His data table and the resulting graph of current versus temperature are works of art, and they allowed him to make sensible component selections for a fixed 250-mA current limit with a reasonably flat thermal response.

As for construction, it’s all classic [DiodeGoneWild], including a PCB with traces ground out with a Dremel and a recycled heat sink. He also dropped a couple of interesting build techniques, like adding leads to turn SMD tantalum caps into through-hole components. The video below shows all the build details along with the exhaustive breadboard testing.

From taking on a potentially risky magnetron teardown to harvesting lasers from headlights, there’s always something to learn from a [DiodeGoneWild] video.

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Getting Started In Ham Hack Chat

June 5, 2023 by 41 Comments

Join us on Wednesday, June 7 at noon Pacific for the Getting Started in Ham Hack Chat with Mark Hughes and Beau Ambur!

If you were to scratch any random hacker from the last 100 years, chances are pretty good you’d find an amateur radio operator just beneath the surface. Radio is the first and foremost discipline where hacking was not only welcomed, but required. If you wanted to get on the air, you sat down with some coils of wire, a few random parts — as often as not themselves homemade — and a piece of an old breadboard, and you got to work. Build it yourself or do without, and when it broke down or you wanted to change bands or add features, that was all on you too.

Like everything else, amateur radio has changed dramatically over the decades, and rolling your own radio isn’t exactly a prerequisite for entry into the ham radio club anymore. Cheap but capable handheld radios are available for a pittance, better quality radios are well within most people’s budget, and commercially available antennas have reduced the need to dabble in that particular black art. The barrier to entry for amateur radio has never been lower; you don’t even have to learn Morse anymore! So why haven’t you gotten a license?

join-hack-chatWhatever your reason for putting off joining the club of licensed amateur radio operators, we’re going to do our best to change your mind. And to help us do that, we’ve asked Mark Hughes (KE6WOB) and Beau Ambur (K6EAU) to swing by the Chat and share their experiences with getting on the air. Both are relatively recent licensees, and they’ll do their best to answer your questions about getting on the air for the first time, to get on your way to building that first radio.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, June 7 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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Hackaday Links: June 4, 2023

June 4, 2023 by 9 Comments

A report released this week suggests that 50 flights into its five-flight schedule, the Mars helicopter might be starting to show its age. The report details a protracted communications outage Ingenuity’s flight controllers struggled with for six sols after flight 49 back in April. At first attributed to a “communications shadow” caused by the helicopter’s robotic buddy, Perseverance, moving behind a rocky outcrop and denying line of sight, things got a little dicey once the rover repositioned and there was still no joy. Since the helicopter has now graduated from “technology demonstration” to a full-fledged member of the team tasked with scouting locations for the rover while respecting the no-fly zone around it, it was essential to get it flying again. Several attempts to upload a flight plan failed with nothing but an acknowledgment signal from the helicopter, but a final attempt got the program uploaded and flight 50 was a complete if belated success. So that’s good, but the worrying news is that since Sol 685, the helicopter has been switching in and out of nighttime survival mode. What that portends is unclear, but no matter how amazing the engineering is, there’s only so much that can be asked on Ingenuity before something finally gives.

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Make Yourself A Megamind With A Hypercentric Camera

June 4, 2023 by 4 Comments

Sometimes, all it takes to learn something new is a fresh perspective on things. But what’s to be learned from reversing your perspective completely with a hypercentric lens? For one thing, that you can make humans look really, really weird.

To be fair, there’s a lot to the optical story here, which [volzo] goes over in ample detail. The short version of it is that with the right arrangement of optical elements, it’s possible to manipulate the perspective of a photograph for artistic effect, up to the point of reversing the usual diminishment of the apparent size of objects in the scene that are farther away from the camera. Most lenses do their best to keep the perspective of the scene out of this uncanny valley, although the telecentric lenses used in some machine vision systems manipulate the perspective to make identical objects within the scene appear to be the same size regardless of their distance from the camera. A hypercentric lens, on the other hand, turns perspective on its head, making near objects appear smaller than far objects, and comically distorts things like the human face.

[volzo]’s hypercentric camera uses a 700-mm focal length Fresnel lens mounted on a motorized gantry, which precisely positions a camera relative to the lens to get the right effect. A Raspberry Pi controls the gantry, but it’s not strictly needed for the hypercentric effect to work. Lighting is important, though, with a ring of LEDs around the main lens providing even illumination of the scene. The whole setup as well as the weirdly distorted portraits that result are shown in the video below.

If these bizarrely distorted faces look familiar, you might be recalling [Curious Marc]’s head-enlarging wearable.

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Getting A Close-Up View Of Chip Formation With An SEM

June 1, 2023 by 16 Comments

When all you’ve got is a hammer, everything looks like a nail. And when you’ve got a scanning electron microscope, everything must look like a sample that would be really, really interesting to see enlarged in all its 3D glory. And this is what [Zachary Tong] delivers with this up close and personal look at the chip formation process.

We’ve got to hand it to [Zach] with this one, because it seems like this was one of those projects that just fought back the whole time. Granted, the idea of cutting metal inside the vacuum chamber of an SEM seems like quite an undertaking right up front. To accomplish this, [Zach] needed to build a custom tool to advance a cutting edge into a piece of stock by tiny increments. His starting point was a simple off-the-shelf linear stage, which needed a lot of prep work before going into the SEM vacuum chamber. The stage’s micrometer advances a carbide insert into a small piece of aluminum 50 microns at a time, raising a tiny sliver of aluminum while it slowly plows a tiny groove into the workpiece.

Getting the multiple shots required to make a decent animation with this rig was no mean feat. [Zach]’s SEM sample chamber doesn’t have any electrical connections, so each of the 159 frames required a painstaking process of advancing the tool, pulling down a vacuum in the chamber, and taking a picture. With each frame taking at least five minutes, this was clearly a labor of love. The results are worth it, though; stitched together, the electron micrographs show the chip formation process in amazing detail. The aluminum oxide layer on the top of the workpiece is clearly visible, as are the different zones of cutting action. The grain of the metal is also clearly visible, and the “gumminess” of the chip is readily apparent too.

For as much work as this was, it seems like [Zach] had things a bit easier than [Ben Krasnow] did when he tried something similar with a much less capable SEM.

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Ask Hackaday: What’s Your “Tactical Tool” Threshold?

May 31, 2023 by 130 Comments

With few exceptions, every field has a pretty modest set of tools that would be considered the minimum for getting most jobs done. A carpenter can make do with tools that would fit in a smallish bag, while a mechanic can handle quite a few repairs with a simple set of socket wrenches and other tools. Even in electronics, a lot of repairs and projects can be tackled with little more than a couple of pairs of pliers, some cutters, and a cheap soldering iron.

But while the basic kit of tools for any job may be enough, there will always be those jobs that need more tools. Oh sure, sometimes you can — and should — make do with what you’ve got; I can’t count the number of times I’ve used an elastic band wrapped around the handles of a pair of needlenose pliers as an impromptu circuit board vise. But eventually, you’re going to come upon a situation where only the “real” tool will do, and substitutes need not apply.

As I look around my shop and my garage, I realize that I may have a problem with these “tactical tool” purchases. I’ve bought so many tools that I’ve used far fewer times than I thought I would, or perhaps even never used, that I’m beginning to wonder if I tackle projects just as an excuse to buy tools. Then again, some of my tactical purchases have ended up being far more useful than I ever intended, which has only reinforced my tendency toward tool collecting. So I thought I’d share a few of my experiences with tactical tools, and see how the community justifies tactical tool acquisitions.

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Open-Source AR Hack Chat

May 29, 2023 by No comments

Join us on Wednesday, May 31 at noon Pacific for the Open-Source AR Hack Chat with Raj Nakaraja!

We may live in a soup of electromagnetic waves that range in wavelength from the diameter of Jupiter down to a fraction of the radius of a hydrogen atom, but our eyeballs have evolved to only let us sense a tiny slice of that spectrum. That’s too bad, really, because there’s a lot going on in the rest of the spectrum that could potentially inform our ROYGBIV-centric view of the world. Think of the possibilities of being able to see UV the way an insect does, or being able to watch the radiation pattern of an antenna and make adjustments on the fly. Sounds like a job for augmented reality.

join-hack-chatIf seeing the world with different eyes sounds as cool to you as it does to us, you won’t want to miss Raj Nakaraja’s stop by the Hack Chat. Raj is head of engineering at Brilliant Labs, an augmented reality company that’s looking to bring AR into the mainstream. They’ve got some cool ideas about AR, and we’re going to take the opportunity to talk to Raj about open-source AR in general, Brilliant’s products specifically, and how AR can be incorporated into not only our projects, but into our lives as well.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, May 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.