Author: Dan Maloney

3300 Articles

Engineering Lessons From The Super-Kamiokande Neutrino Observatory Failure

January 9, 2025 by 48 Comments

Every engineer is going to have a bad day, but only an unlucky few will have a day so bad that it registers on a seismometer.

We’ve always had a morbid fascination with engineering mega-failures, few of which escape our attention. But we’d never heard of the Super-Kamiokande neutrino detector implosion until stumbling upon [Alexander the OK]’s video of the 2001 event. The first half of the video below describes neutrinos in some detail and the engineering problems related to detecting and studying a particle so elusive that it can pass through the entire planet without hitting anything. The Super-Kamiokande detector was built to solve that problem, courtesy of an enormous tank of ultrapure water buried 1,000 meters inside a mountain in Japan and lined with over 10,000 supersized photomultiplier tubes to detect the faint pulses of Chernkov radiation emitted on the rare occasion that a neutrino interacts with a water molecule.

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Retrotechtacular: Soldering The Tek Way

January 9, 2025 by 40 Comments

For a lot of us, soldering just seems to come naturally. But if we’re being honest, none of us was born with a soldering iron in our hand — ouch! — and if we’re good at soldering now, it’s only thanks to good habits and long practice. But what if you’re a company that lives and dies by the quality of the solder joints your employees produce? How do you get them to embrace the dark art of soldering?

If you’re Tektronix in the late 1970s and early 1980s, the answer is simple: make in-depth training videos that teach people to solder the Tek way. The first video below, from 1977, is aimed at workers on the assembly line and as such concentrates mainly on the practical aspects of making solid solder joints on PCBs and mainly with through-hole components. The video does have a bit of theory on soldering chemistry and the difference between eutectic alloys and other tin-lead mixes, as well as a little about the proper use of silver-bearing solders. But most of the time is spent discussing the primary tool of the trade: the iron. Even though the film is dated and looks like a multi-generation dupe from VHS, it still has a lot of valuable tips; we’ve been soldering for decades and somehow never realized that cleaning a tip on a wet sponge is so effective because the sudden temperature change helps release oxides and burned flux. The more you know.

The second video below is aimed more at the Tek repair and rework technicians. It reiterates a lot of the material from the first video, but then veers off into repair-specific topics, like effective desoldering. Pro tip: Don’t use the “Heat and Shake” method of desoldering, and wear those safety glasses. There’s also a lot of detail on how to avoid damaging the PCB during repairs, and how to fix them if you do manage to lift a trace. They put a fair amount of emphasis on the importance of making repairs look good, especially with bodge wires, which should be placed on the back of the board so they’re not so obvious. It makes sense; Tek boards from the era are works of art, and you don’t want to mess with that.

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All-Band Receiver Lets You Listen To All The Radio At Once

January 9, 2025 by 52 Comments

There are many ways to build a radio receiver, but most have a few things in common, such as oscillators, tuned circuits, detectors, mixers, and amplifiers. Put those together in the right order and you’ve got a receiver ready to tune in whatever you want to listen to. But if you don’t really care about tuning and want to hear everything all at once, that greatly simplifies the job and leaves you with something like this homebrew all-band receiver.

Granted, dispensing with everything but a detector and an audio amplifier will seriously limit any receiver’s capabilities. But that wasn’t really a design concern for [Ido Roseman], who was in search of a simple and unobtrusive way to monitor air traffic control conversations while flying. True, there are commercially available radios that tune the aviation bands, and there are plenty of software-defined radio (SDR) options, but air travel authorities and fellow travelers alike may take a dim view of an antenna sticking out of a pocket.

So [Ido] did a little digging and found a dead-simple circuit that can receive signals from the medium-wave bands up into the VHF range without regard for modulation. The basic circuit is a Schottky diode detector between an antenna and a high-gain audio amplifier driving high-impedance headphones; [Ido] built a variation that also has an LM386 amplifier stage to allow the use of regular earbuds, which along with a simple 3D-printed case aids in the receiver’s stealth.

With only a short piece of wire as an antenna, reception is limited to nearby powerful transmitters, but that makes it suitable for getting at least the pilot side of ATC conversations. It works surprisingly well — [Ido] included a few clips that are perfectly understandable, even if the receiver also captured things like cell phones chirping and what sounds like random sferics. It seems like a fun circuit to play with, although with our luck we’d probably not try to take it on a plane.

Making Sure Your Patch Cables Are Ready For RF Work

January 8, 2025 by 3 Comments

How do you know that your patch cables are good? For simple jumper wires, a multimeter is about all you need to know for sure. But things can get weird in the RF world, in which case you might want to keep these coaxial patch cable testing tips in mind.

Of course, no matter how high the frequency, the basics still apply, and [FesZ] points out in the video below that you can still get a lot of mileage out of the Mark 1 eyeball and a simple DMM. Visual inspection of the cable and terminations can reveal a lot, as can continuity measurements on both the inner and outer conductors. Checking for shorts between conductors is important, too. But just because the cable reads good at DC doesn’t mean that problems aren’t still lurking. That’s when [FesZ] recommends breaking out a vector network analyzer like the NanoVNA. This tool will allow you to measure the cable’s attenuation and return loss parameters across the frequency range over which the cable will be used.

For stubborn problems, or just for funsies, there’s also time-domain reflectometry, which can be done with a pulse generator and an oscilloscope to characterize impedance discontinuities in the cable. We’ve covered simple TDR measurement techniques before, but [FesZ] showed a neat trick called time-domain transformation, which uses VNA data to visualize the impedance profile of the whole cable assembly, including its terminations.

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Rethinking Your Jellybean Op Amps

January 6, 2025 by 44 Comments

Are your jellybeans getting stale? [lcamtuf] thinks so, and his guide to choosing op-amps makes a good case for rethinking what parts you should keep in stock.

For readers of a certain vintage, the term “operational amplifier” is almost synonymous with the LM741 or LM324, and with good reason. This is despite the limitations these chips have, including the need for bipolar power supplies at relatively high voltages and the need to limit the input voltage range lest clipping and distortion occur. These chips have appeared in countless designs over the nearly 60 years that they’ve been available, and the Internet is littered with examples of circuits using them.

For [lcamtuf], the abundance of designs for these dated chips is exactly the problem, as it leads to a “copy-paste” design culture despite the far more capable and modern op-amps that are readily available. His list of preferred jellybeans includes the OPA2323, favored thanks to its lower single-supply voltage range, rail-to-rail input and output, and decent output current. The article also discussed the pros and cons of FET input, frequency response and slew rate, and the relative unimportance of internal noise, pointing out that most modern op-amps will probably be the least thermally noisy part in your circuit.

None of this is to take away from how important the 741 and other early op-amps were, of course. They are venerable chips that still have their place, and we expect they’ll be showing up in designs for many decades to come. This is just food for thought, and [lcamtuf] makes a good case for rethinking your analog designs while cluing us in on what really matters when choosing an op-amp.

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Hackaday Links: January 5, 2025

January 5, 2025 by 4 Comments

Good news this week from the Sun’s far side as the Parker Solar Probe checked in after its speedrun through our star’s corona. Parker became the fastest human-made object ever — aside from the manhole cover, of course — as it fell into the Sun’s gravity well on Christmas Eve to pass within 6.1 million kilometers of the surface, in an attempt to study the extremely dynamic environment of the solar atmosphere. Similar to how manned spacecraft returning to Earth are blacked out from radio communications, the plasma soup Parker flew through meant everything it would do during the pass had to be autonomous, and we wouldn’t know how it went until the probe cleared the high-energy zone. The probe pinged Earth with a quick “I’m OK” message on December 26, and checked in with the Deep Space Network as scheduled on January 1, dumping telemetry data that indicated the spacecraft not only survived its brush with the corona but that every instrument performed as expected during the pass. The scientific data from the instruments won’t be downloaded until the probe is in a little better position, and then Parker will get to do the whole thing again twice more in 2025. Continue reading “Hackaday Links: January 5, 2025” →

Pi Pico Makes SSTV Reception A Snap

January 4, 2025 by 10 Comments

There’s a paradox in amateur radio: after all the time and effort spent getting a license and all the expense of getting some gear together, some new hams suddenly find that they don’t have a lot to talk about when they get in front of the mic. While that can be awkward, it’s not a deal-breaker by any means, especially when this Pi Pico SSTV decoder makes it cheap and easy to get into slow-scan television.

There’s not much to [Jon Dawson]’s SSTV decoder. Audio from a single-sideband receiver goes through a biasing network and into the Pico’s A/D input. The decoder can handle both Martin and Scottie SSTV protocols, with results displayed on a TFT LCD screen. The magic is in the software, of course, and [Jon] provides a good explanation of the algorithms he used, as well as some of the challenges he faced, such as reliably detecting which protocol is being used. He also implemented correction for “slant,” which occurs when the transmitter sample rate drifts relative to the receiver. Fixing that requires measuring the time it took to transmit each line and adjusting the timing of the decoder to match. The results are dramatic, and it clears up one of the main sources of SSTV artifacts.

We think this is a great build, and simple enough that anyone can try it. The best part is that since it’s receive-only, it doesn’t require a license, although [Jon] says he’s working on an encoder and transmitter too. We’re looking forward to that, but in the meantime, you might just be able to use this to capture some space memes.

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