Lessons Learned From A High-Voltage Power Supply

January 18, 2024 by 8 Comments

When you set out to build a 60,000-volt power supply and find out that it “only” delivers a measly 50,000 volts, you naturally have to dive in and see where things can be improved. And boy, did [Advanced Tinkering] find some things to improve.

First things first: if you haven’t seen [Advanced]’s first pass at a high-voltage supply, you should go check that out. We really liked the design of that one, and were particularly impressed with the attention to detail, all of which seemed to be wisely geared to the safe operation of the supply. But as it turns out, the margin of safety in the original design wasn’t as good as it could be. Of most concern was the need to physically touch the supply to control it, an obvious problem should something go wrong anywhere along the HV path, which includes a ZVS-driven flyback and an epoxy-potted Crockcroft-Walton voltage multiplier.

To make things a little more hands-off, [AT] added a pneumatically actuated switch to the supply, along with some indicator lights to help prevent him from leaving the supply powered up. He also reworked the low-voltage DC supply section, replacing a fixed-voltage supply and a DC-DC converter with a variable DC supply. This had the side benefit of providing a little bit more voltage to the ZVS driver, which goosed up the HV output a bit. The biggest change, though, was to the potted part of the HV section, which showed signs of arcing to the chassis. It turns out that even at 100% infill, 3D printed PLA isn’t a great choice for HV projects; more epoxy was the answer to that problem. Along with rewinding the primary on the flyback transformer, the power supply not only hit the 60-kV spec, but even went a little past that — and all without any of that pesky arcing.

We thought [Advanced Tinkering]’s first pass on this build was pretty slick, but we’re glad to see that it’s even better now. And we’re still keen to see how this supply will be put to use; honestly, the brief teaser at the end of the video wasn’t much help in guessing what it could be.

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Crippled Peregrine Lander To Make Fiery Return Home

January 18, 2024 by 9 Comments

Within a few hours of this post going live, Astrobotic’s Peregrine spacecraft is expected to burn up in the Earth’s atmosphere — a disappointing end to a mission that was supposed to put the first US lander on the Moon since the Apollo program ended in 1972.

In their twentieth mission update since Peregrine was carried into space on the inaugural flight of the United Launch Alliance Vulcan Centaur rocket, Astrobotic explains that the craft has been put on a trajectory designed to ensure it breaks up over a remote area of the South Pacific.

Predicted re-renty point for the Peregrine lander.

It was previously hoped the lander, which suffered a severe system malfunction just hours after liftoff, could have at least made a close pass of the Moon in lieu of touching down. But mission controllers felt the more responsible approach was to have Peregrine make a controlled re-entry while they still had the ability to maneuver it. The alternative, allowing the craft to remain in an uncontrolled orbit between the Earth and Moon, could potentially have caused problems for future Artemis missions.

Over the last ten days, ground controllers at Astrobotic have been working to piece together what happened to the doomed lander, while at the same time demonstrating a remarkable level of transparency by keeping the public informed along the way. It’s now believed that the stream of gas being expelled from a rupture in one of the craft’s propellant tanks was acting as a sort of impromptu thruster. This not only made the craft difficult to keep oriented, but also wasted the propellants that were necessary to perform a soft landing on the lunar surface.

Although the craft was eventually brought under control, the damage to the mission had already been done. While this obviously isn’t the ending that Astrobotic was hoping for, we have no doubt that the company collected valuable data during the craft’s flight through space, which took it approximately 390,000 kilometers (242,000 miles) from Earth.

As for us space nerds, we won’t have to wait long before another lunar lander makes its attempt. Japan’s Smart Lander for Investigating Moon (SLIM) should be touching down at around 10 AM Eastern on Friday (YouTube Live Stream), and the Nova-C lander from Intuitive Machines is scheduled to be launched aboard a Falcon 9 rocket sometime next month.

Tech In Plain Sight: Windshield Frit

January 18, 2024 by 29 Comments

You probably see a frit every day and don’t even notice it. What is it? You know the black band around your car’s windshield? That’s a frit (which, by the way, can also mean ingredients used in making glass) or, sometimes, a frit band. What’s more, it probably fades out using a series of dots like a halftone image, right? Think that’s just for aesthetics? Think again.

Older windshields were not always attached firmly, leading to them popping out in accidents. At some point, though, the industry moved to polyurethane adhesives, which are superior when applied correctly. However, they often degrade from exposure to UV. That’s a problem with a windshield, which usually gets plenty of sunlight.

The answer is the frit, a ceramic-based baked-on enamel applied to both sides of the windshield’s edges, usually using silk screening. The inner part serves as a bonding point for the adhesive. However, the outer part blocks UV radiation from reaching the adhesive. Of course, it also hides the adhesive and any edges or wiring beneath it, too.

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Deep Dive Into 3D Printing Nozzles

January 18, 2024 by 14 Comments

[Lost in Tech] set out to examine a variety of 3D printing nozzles. Before he got there, though, he found some issues. In particular, he found that his current crop of printers don’t take the standard E3D or MK8 nozzles. So, instead, he decided to examine various nozzles under the microscope.

Unsurprisingly, each nozzle had a tiny hole at the end, although the roundness of the hole varied a bit from nozzle to nozzle. As you might expect, more expensive nozzles had better orifices than the cheap ones. Grabbing pictures of nozzles at magnification isn’t easy, so he set up a special image stacking setup to get some beautiful images (and he has another video on how that works).

But the real star of the video is when he virtually travels into the orifice to show the innermost details of the nozzle from the inside out. This let him visualize the smoothness and finish. The Creality nozzles looked very good and weren’t terribly expensive. Many of the expensive nozzles were quite good. However, as you would expect, the quality of cheap nozzles were all over the place.

By the end, [Lost in Tech] speculates if the non-standard nozzles are a way to prevent you from buying low-cost nozzles and eating into sales or if they are a way to prevent you from buying low-cost nozzles that may give you poor print quality. What do you think?

There’s more than one way to look inside a nozzle. We just buy our nozzles, but some people make their own.

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Predicting The A-Bomb: The Cartmill Affair

January 18, 2024 by 18 Comments
The cover of the infamous issue of Astounding, March 1944

There’s an upcoming movie, Argylle, about an author whose spy novels are a little too accurate, and she becomes a target of a real-life spy game. We haven’t seen the movie, but it made us think of a similar espionage caper from 1944 involving science fiction author Cleve Cartmill. The whole thing played out in the pages of Astounding magazine (now Analog) and involved several other science fiction luminaries ranging from John W. Campbell to Isaac Asimov. It is a great story about how science is — well, science — and no amount of secrecy or legislation can hide it.

In 1943, Cartmill queried Campbell about the possibility of a story that would be known as “Deadline.” It wasn’t his first story, nor would it be his last. But it nearly put him in a Federal prison. Why?  The story dealt with an atomic bomb.

Nothing New

By itself, that’s probably not a big deal. H.G. Wells wrote “The World Set Free” in 1914, where he predicted nuclear weapons. But in 1914, it wasn’t clear how that would work exactly. Wells mentioned “uranium and thorium” and wrote a reasonable account of the destructive power: Continue reading “Predicting The A-Bomb: The Cartmill Affair” →

A Dim Bulb Tester Is For Testing Other Equipment, Not Bulbs

January 18, 2024 by 26 Comments

If you’re testing old stereo equipment, a dim bulb tester can really come in handy. It’s not for testing bulbs, though, it’s a tester that uses a dim bulb to test other things. [Nicholas Morganti] explains it all in his guide to making your own example of such a tool. Just be wary — you need to know what you’re doing with mains voltages to do this safely!

The dim bulb is a deceptively simple tool that nonetheless often proves useful in diagnostics. It normally just consists of a bulb connected in series with the equipment under test. The bulb is intended to be a similar wattage to the power draw of the equipment itself. Take for example, an amplifier. If the bulb glows brightly when the amp is under no load, it suggests there may be a short circuit somewhere. That’s because the glowing bulb indicates that plenty of current is being drawn under a condition when very little should be flowing. The bulb protects the equipment by essentially acting as a bit of a current limiting device. It’s a soft-start tool for a piece of vulnerable equipment.

Building one is usually as simple as gathering an enclosure, a plug receptacle, a bulb socket, and some other ancillary parts to lace everything together. [Nicholas] explains it all with clear diagrams and tells you how to follow along. It’s easy enough, but you really need to know what you’re doing to use one safely, as mains voltages are involved.

It’s a great tool to have if you’re getting into amplifier repair or similar work on old gear. If you’ve been whipping up your own must-have tools, don’t hesitate to let us know!

Android-Powered Rigol Scopes Go Wireless

January 18, 2024 by 9 Comments

The Rigol DHO800 and DHO900 series use Android underneath, and as you might expect, this makes them easier to hack. A case in point: [VoltLog] demonstrates that you can add WiFi to the scope using a cheap USB WiFi adapter. This might seem like a no-brainer on the surface, but because the software doesn’t know about WiFi, there are a few minor hoops to jump through.

The first issue is that you need a WiFi adapter the built-in OS already knows how to handle. The community has identified at least one RTL chipset that works and it happens to be in the TP-Link TL-WN725N. These are old 2.4 GHz only units, so they are widely available for $10 or less.

But even with the correct hardware, the scope doesn’t have any menus to configure the WiFi interface. To solve that, you need to temporarily use a USB hub and a USB keyboard. Once you have everything plugged in, you can use the Super + N keyboard shortcut to open up the Android notification bar, which is normally hidden. Once you’ve setup the network connection, you won’t need the keyboard anymore.

Or maybe not — it turns out the keyboard does allow you to change a few other things. For example, [VoltLog] used it to increase the screen brightness more than the default maximum setting.

The only other issue appears to be that the scope shows it is disconnected even when connected to WiFi. That doesn’t seem to impact operation, though. Of course, you could use a WiFi to Ethernet bridge or even an old router, but now you have a cable, a box, and another power cord to deal with. This solution is neat and clean. You bet we’ve already ordered a TP-Link adapter!

WiFi scopes are nothing new. We suspect Rigol didn’t want to worry about interference and regulatory acceptance, but who knows? Besides, it is fun to add WiFi to wired devices.

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