Author: Dan Maloney

3287 Articles

Tiny POV Turns Right Round For Volumetric Fun

December 3, 2023 by 13 Comments

Just when you think the POV thing has run out of gas, along comes [mitxela] to liven things up. In this, he’s taken the whole persistence of vision display concept and literally spun up something very cool: a tiny volumetric “electric candle” display.

As he relates the story, the idea came upon him on a night out at the pub, which somehow led to the idea of an electric candle. Something on the scale of a tea light would fit [mitxela]’s fascination with very small and very interesting circuits, so it was off to the races. Everything needed — motor, LIR2450 coin cell, RP2040, and the vertical matrix of LEDs — fits into the footprint of the motor, which was salvaged from a CD drive. To avoid the necessity of finding or building a tiny slip-ring, he instead fixed everything to the back of the motor and attached its shaft to a Delrin baseplate.

The 8×10 array of surface-mount LEDs stands atop the RP2040 with the help of some enameled magnet wire, itself a minor bit of circuit sculpture. There’s also a 3D-printed holder for a phototransistor and IR LED, which form a sensor to trigger the display; you can see [mitxela] using a finger to turn the display off and move it back and forth. It goes without saying that these things always look better in person than they do in stills or even on video, but we still think it looks fantastic. There’s also a deep dive into generating volumetric data in the write-up, as well as an unexpected foray into the fluid dynamics calculations needed to create a realistic flame effect for the candle.

All in all, this is a fantastic if somewhat fragile project. We love the idea of putting this in a glass enclosure to make it look a little like a Nixie tube, too.

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Simple Chemistry To Metallize And Etch Silicon Chips

December 3, 2023 by 5 Comments

We’ve been eagerly following [ProjectsInFlight]’s stepwise journey toward DIY semiconductors, including all the ups and downs, false leads, and tedious optimizations needed to make it possible for the average hacker to make chips with readily available tools and materials.

Next up is metallization, and spoiler alert: it wasn’t easy. In a real fab, metal layers are added to chips using some form of deposition or sputtering method, each of which needs some expensive vacuum equipment. [ProjectsInFlight] wanted a more approachable way to lay down thin films of metal, so he turned to an old friend: the silver mirror reaction. You may have seen this demonstrated in high school chemistry; a preparation of Tollen’s reagent, a mix of sodium hydroxide, ammonia, and silver nitrate, is mixed with glucose in a glass vessel. The glucose reduces the reagent, leaving the metallic silver to precipitate on the inside of the glass, which creates a beautiful silvered effect.

Despite some issues, the silvering method worked well enough on chips to proceed on, albeit carefully, since the layer is easily scratched off. [ProjectsInFlight]’s next step was to find an etchant for silver, a tall order for a noble metal. He explored piranha solutions, which are acids spiked with peroxide, and eventually settled on plain old white vinegar with a dash of 12% peroxide. Despite that success, the silver layer was having trouble sticking to the chip, much preferring to stay with the photoresist when the protective film was removed.

The solution was to replace the photoresist’s protective film with Teflon thread-sealing tape. That allowed the whole process from plating to etching to work, resulting in conductive traces with pretty fine resolution. Sure they’re a bit delicate, but that’s something to address another day. He’s come a long way from his DIY tube furnace used to put down oxide layers, and suffering through the search for oxide etchants and exploring photolithography methods. It’s been a fun ride so far, and we’re eager to see what’s next.

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Hackaday Podcast Episode 246: Bypassing Fingerprint Readers Is Easy, Killing Memory Chips Is Hard, Cell Phones Vs Sperm

December 1, 2023 by No comments

It’s the week after Thanksgiving (for some of us) and if you’re sick of leftovers, you’re in luck as Elliot and Dan get together to discuss the freshest and best inter-holiday hacks. We’ll cue up the “Mission: Impossible” theme for a self-destructing flash drive with a surprising sense of self-preservation, listen in on ET only to find out it’s just a meteor, and look for interesting things to do with an old 3D printer. We’ll do a poking around a little in the basement at Tektronix, see how easy it is to spoof biometric security, and get into a love-hate relationship with both binary G-code and bowling balls with strings attached. What do you do with a box full of 18650s? Easy — make a huge PCB to balance them the slow way. Is your cell phone causing a population crisis? Is art real or AI? And what the heck is a cannibal CME? Tune in as we dive into all this and more.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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Retrotechtacular: Studio Camera Operation, The BBC Way

November 26, 2023 by 11 Comments

If you ever thought that being a television camera operator was a simple job, this BBC training film on studio camera operations will quickly disabuse you of that notion.

The first thing that strikes you upon watching this 1982 gem is just how physical a job it is to stand behind a studio camera. Part of the physicality came from the sheer size of the gear being used. Not only were cameras of that vintage still largely tube-based and therefore huge — the EMI-2001 shown has four plumbicon image tubes along with tube amplifiers and weighed in at over 100 kg — but the pedestal upon which it sat was a beast as well. All told, a camera rig like that could come in at over 300 kg, and dragging something like that around a studio floor all day under hot lights had to be hard. It was a full-body workout, too; one needed a lot of upper-body strength to move the camera up and down against the hydropneumatic pedestal cylinder, and every day was leg day when you had to overcome all that inertia and get the camera moving to your next mark.

Operating a beast like this was not just about the bull work, though. There was a lot of fine motor control needed too, especially with focus pulling. The video goes into a lot of detail on maintaining a smooth focus while zooming or dollying, and shows just how bad it can look when the operator is inexperienced or not paying attention. Luckily, our hero Allan is killing it, and the results will look familiar to anyone who’s ever seen any BBC from the era, from Dr. Who to I, Claudius. Shows like these all had a distinctive “Beeb-ish” look to them, due in large part to the training their camera operators received with productions like this.

There’s a lot on offer here aside from the mechanical skills of camera operation, of course. Framing and composing shots are emphasized, as are the tricks to making it all look smooth and professional. There are a lot of technical details buried in the video too, particularly about the pedestal and how it works. There are also two follow-up training videos, one that focuses on the camera skills needed to shoot an interview program, and one that adds in the complications that arise when the on-air talent is actually moving. Watch all three and you’ll be well on your way to running a camera for the BBC — at least in 1982.

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Double-Dose Of AI Turns Daily Tasks Into Works Of Art

November 25, 2023 by 11 Comments

Not so long ago, “Magic Mirror” builds were all the rage, and we have to admit getting out daily reminders and newsfeeds on an LCD display sitting behind a partially reflective mirror is not without its charms. But styles ebb and flow, so we don’t see too many of those builds anymore. This e-ink daily calendar reminder hearkens back to those Magic Mirrors, only with a double twist of AI.

This project is the work of [Ilkka Turunen], and right up front we’ll say the results are just gorgeous. A lot of that has to do with the 10.3″ e-ink display used, but more with the creative use of not one but two machine learning systems. The first is ChatGPT, which [Ilkka] uses to parse the day’s online calendar entries and grab the most significant events to generate a prompt for DALL-E. The generated DALL-E prompt has specific instructions that guide the style of the image, which honestly is where most of the artistry lies. [Ilkka]’s aesthetic choices, like suggesting that the images look like a 19th-century lithograph or a satirical comic from a turn-of-the-(last)-century newspaper. The prompt is then sent off to DALL-E for rendering, and the resulting image is displayed.

It has to be said that the prompts that ChatGPT generates based on the combination of [Ilkka]’s aesthetic preferences and the random events of the day are strikingly complex. The chatbot really seems to be showing some imagination these days; DALL-E is no slouch either in turning those words into images.

Like the idea of an e-ink daily reminder but prefer a less artistic presentation? This should help.

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Fail Of The Week: This Flash Drive Will NOT Self-Destruct In Five Seconds

November 25, 2023 by 49 Comments

How hard can it be to kill a flash drive? Judging by the look of defeat on [Walker]’s face in the video below, pretty darn hard.

To bring you up to speed, and to give the “Mission: Impossible” reference in the title some context, it might be a good idea to look over our earlier coverage of [Walker]’s Ovrdrive project. It started way back in 2022 with the idea that some people might benefit from a flash drive that could rapidly and covertly render the data stored on it, err, “forensically unavailable.” This would require more than just erasing the data, of course, so [Walker] began looking at ways to physically kill a memory chip. First up was a voltage doubler to apply voltage much greater than the absolute maximum rating of 4.6 V for any pin on the chip. That corrupted some files on the flash chip, enough of a win to proceed to a prototype that actually succeeded in releasing the Magic Smoke.

But sadly, that puff of smoke ended up being a fluke. [Walker] couldn’t repeat the result, at least not with the reliability required by people for whom data privacy is literally a life-or-death matter. To increase the odds of a kill, he came up with an H-bridge circuit to reverse the polarity of the memory chip’s supply. Surely that would kill the chip, and from the thermal camera images, it sure looked promising. But apparently, even 167°C isn’t enough to forensically disable the chip, which kind of makes sense from the point of view of reflow survivability.

What’s next for [Walker]? He says he’s going to team up his overvoltage and reverse-polarity methods for one last shot, but after that, he’s about out of reasonable options. Sure, a thermite charge or a vial of superacid would do the trick, but neither is terribly covert. If you’re going to go that way, you might as well just buy a standard flash drive and throw it in the microwave or a blender. And we need to remember that this may be something the drive’s owner needs to do with jack-booted thugs kicking in the door, or possibly at gunpoint. It wouldn’t do to be too conspicuous under such circumstances. That’s why we like the “rapid power cycling” method of triggering the drive’s self-destruct sequence; it could easily be disguised as shaking hands in a stressful situation.

Who knew that memory chips were this robust? Kudos to [Walker] for getting the project as far as he did, and we’re still rooting for him to make it work somehow.

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The Other Kind Of Static Hazard To Your Logic Circuits

November 24, 2023 by 21 Comments

We’ve all heard of the dangers of static electricity when dealing with electronics, and we all take the proper precautions when working with static-sensitive components — don’t we? But as much as we fear punching an expensive hole in a chip with an errant spark, electrostatic discharge damage isn’t the only kind of static hazard your digital designs can face.

To be fair, the static hazard demonstrated by [Shane Oberloier] in the video below isn’t really an electrostatic problem. “Static” in this case refers to when a change to an input of a logic circuit gives an unexpected output until the circuit stabilizes. The circuit shown is pretty simple, with three inputs going into a combination of AND and NOT gates before going into an OR gate. The static hazard manifests as a glitch in the output when the middle input line’s logical state is toggled; according to the circuit’s truth table, the output shouldn’t change under these conditions, but the oscilloscope clearly captures a high-low-high blip. [Dr. Shane]’s explanation of why this happens makes perfect sense: the inverter on that input line has a brief but non-zero propagation time, putting the whole circuit in an ambiguous state before finally settling down to the correct output value.

So how do you fix something like this? This gets into the Boolean weeds a bit, and we won’t pretend to fully understand it, but at least for this case, [Dr. Shane] was able to add a single AND gate to sum the two other inputs and pipe the output into another input of the OR gate. That has the effect of canceling out the race condition caused by the inverter, but at the expense of a more complicated circuit, of course.

We found this to be a fascinating and informative discussion of a potential pitfall in logic design. But, if you still want to see some MOSFETs executed with static electricity, who are we to object?

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