Raspberry Pi Hack Chat With Eben Upton

January 13, 2025 by Dan Maloney 18 Comments

Join us on Wednesday, January 15 at noon Pacific for the Raspberry Pi Hack Chat with Eben Upton!

The Hack Chat has been on an extended hiatus, but we’re back for 2025 and coming strong out of the gate! We’ve been trying to get Raspberry Pi co-founder and CEO Eben Upton on the chat for a while, but there was that whole thing of taking the company public that probably distracted him a wee bit. That’s fine though, because we know he loves getting in the trenches with the hacker community and talking about the things we all love to talk about. It’s not often that you get a chance for a one-on-one like this, so make sure you join us with all your Pi-related questions.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, January 15 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

[Image credit: Sniper Zeta, CC BY-SA 4.0]

Hackaday Links: January 12, 2025

January 12, 2025 by Dan Maloney 5 Comments

The big news story of the week of course has been the wildfires in California, which as of Saturday have burned over 30,000 acres, destroyed 12,000 structures, caused 150,000 people to evacuate, and killed eleven people. Actually, calling them wildfires underplays the situation a bit because there are places where they’ve clearly become firestorms, burning intensely enough to create their own winds, consuming everything in their path in a horrific positive feedback loop. We’ve even seen fire tornados caught on video. We’ve got quite a few connections to the affected area, both personally and professionally, not least of which are all our Supplyframe colleagues in Pasadena, who are under immediate threat from the Eaton fire. We don’t know many details yet, but we’ve heard that some have lost homes. We’ve also got friends at the Jet Propulsion Labs, which closed a few days ago to all but emergency personnel. The fire doesn’t seem to have made it down the mountain yet, but it’s very close as of Saturday noon.

Continue reading “Hackaday Links: January 12, 2025” →

Springs And Things Make For A Unique Timepiece

January 10, 2025 by Dan Maloney 10 Comments

You never know when inspiration is going to strike, and for [Ekaggrat Singh Kalsi], it struck while he was playing with one of his daughter’s hair ties. The result is a clock called “Bezicron” and it’s a fascinating study in mechanical ingenuity.

The hair ties in question are simple objects, just a loose polymer coil spring formed into a loop that can be wrapped around ponytails and the like. In Bezicron, though, each digit is formed by one of these loops fixed to the ends of five pairs of arms. Each pair moves horizontally thanks to a cam rotating between them, changing the spacing between them and moving the hair tie. This forms each loop into an approximation of each numeral, some a little more ragged than others but all quite readable. The cams move thanks to a geared stepper motor on the rightmost digit of the hours and minutes section of the clock, with a gear train carrying over to the left digit. In between is the colon, also made from springy things pulsing back and forth to indicate seconds. The video below shows the clock going through its serpentine motions.

For our money, the best part of this build is the cams. Coming up with the proper shape for those had to be incredibly tedious, although we suspect 3D printing and rapid iterative design were a big help here. Practice with cam design from his earlier Eptaora clock probably helped too.

Continue reading “Springs And Things Make For A Unique Timepiece” →

RISC-V Microcontroller Lights Up Synth With LED Level Meter

January 10, 2025 by Dan Maloney 8 Comments

The LM3914 LED bar graph driver was an amazing chip back in the day. Along with the LM3915, its logarithmic cousin, these chips gave a modern look to projects, allowing dancing LEDs to stand in for a moving coil meter. But time wore on and the chips got harder to find and even harder to fit into modern projects, what with their giant DIP-18 footprint. What’s to be done when a project cries out for bouncing LEDs? Simple — get a RISC-V microcontroller and roll your own LED audio level meter.

In fairness, “simple” isn’t exactly what comes to mind while reading [svofski]’s write-up of this project. It’s part of a larger build, a wavetable synth called “Pétomane Ringard” which just screams out for lots of blinky LEDs. [svofski] managed to squeeze 20 small SMD LEDs onto the board along with a CH32V003 microcontroller. The LEDs are charlieplexed, using five of the RISC-V chip’s six available GPIO lines, leaving one for the ADC input. That caused a bit of trouble with programming, since one of those pins is needed to connect to the programmer. This actually bricked the chip, thankfully only temporarily since there’s a way to glitch the chip back to life, but only after pulling it out of the circuit. [svofski] recommends adding a five-second delay loop to the initialization routine to allow time to recover if the microcontroller gets into an unprogrammable state. Good tip.

As for results, we think the level meter looks fantastic. [svofski] went for automated assembly of the 0402 LEDs, so the strip is straight and evenly spaced. The meter seems to be quite responsive, and the peak hold feature is a nice touch. It’s nice to know there’s a reasonable substitute for the LM391x chips, especially now that all the hard work has been done.
Continue reading “RISC-V Microcontroller Lights Up Synth With LED Level Meter” →

Engineering Lessons From The Super-Kamiokande Neutrino Observatory Failure

January 9, 2025 by Dan Maloney 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.

Continue reading “Engineering Lessons From The Super-Kamiokande Neutrino Observatory Failure” →

Retrotechtacular: Soldering The Tek Way

January 9, 2025 by Dan Maloney 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.

Continue reading “Retrotechtacular: Soldering The Tek Way” →

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

January 9, 2025 by Dan Maloney 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.