Hackaday Podcast Episode 333: Nightmare Whiffletrees, 18650 Safety, And A Telephone Twofer

August 15, 2025 by Kristina Panos 8 Comments

This week, Hackaday’s Elliot Williams and Kristina Panos met up over the tubes to bring you the latest news, mystery sound, and of course, a big bunch of hacks from the previous week.

In Hackaday news, get your Supercon 2025 tickets while they’re hot! Also, the One Hertz Challenge ticks on, but time is running out. You have until Tuesday, August 19th to show us what you’ve got, so head over to Hackaday.IO and get started now. Finally, its the end of eternal September as AOL discontinues dial-up service after all these years.

On What’s That Sound, Kristina got sort of close, but this is neither horseshoes nor hand grenades. Can you get it? If so, you could win a limited edition Hackaday Podcast t-shirt!

After that, it’s on to the hacks and such, beginning with a talking robot that uses typewriter tech to move its mouth. We take a look at hacking printed circuit boards to create casing and instrument panels for a PDP-1 replica. Then we explore a fluid simulation business card, witness a caliper shootout, and marvel at one file in six formats. Finally, it’s a telephone twofer as we discuss the non-hack-ability of the average smart phone, and learn about what was arguably the first podcast.

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!

Download in DRM-free MP3 and savor at your leisure.

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The WHY 2025 Badge And Its 18650s

August 12, 2025 by Jenny List 37 Comments

The largest European hacker camp this year was in the Netherlands — What Hackers Yearn (WHY) 2025 is the latest in the long-running series of four-yearly events from that country, and 2025 saw a move from the Flevoland site used by SHA2017 and MCH2021, back to just north of Alkmaar in Noord-Holland, where the OHM2013 event took place. WHY has found itself making the news in the Dutch technical media for all the wrong reasons over the last few days, after serious concerns were raised about the fire safety of its badge.

The cell supplied with a WHY 2025 badge, with very clear fire safety warning — This is the cell supplied with the WHY badge, complete with manufacturer’s warning.

The concerns were raised from the RevSpace hackerspace in Leidschendam, and centre around the design of the battery power traces on the PCB between the battery holders and the power supply circuitry. Because the 18650 cells supplied with that badge lack any protection circuitry, bridging the power traces could be a fire risk.

In short: their report names the cell holders as having tags too large for their pads on the PCB, a too-tight gap between positive and negative battery traces, protected only by soldermask, and the inadequacy of the badge’s short circuit protection. In the event that metal shorted these battery tags, or wore through the soldermask, the batteries would be effectively shorted, and traces or components could get dangerously hot.

The WHY organizers have responded with a printed disclaimer leaflet warning against misuse of the cells, and added a last-minute epoxy coating to the boards to offer additional protection. Some people are 3D-printing cases, which should also help reduce the risk of short-circuiting due to foreign metal objects. Using an external powerbank with short-circuit protection instead of the cells would solve the problem as well. Meanwhile a group of hackers collecting aid for Ukraine are accepting the batteries as donations.

It’s understood that sometimes bugs find their way into any project, and in that an event badge is no exception. In this particular case, the original Dutch badge team resigned en masse at the start of the year following a disagreement with the WHY2025 organizers, so this badge has been a particularly hurried production. Either way, we are fortunate that the issue was spotted, and conference organizers took action before any regrettable incidents occurred.

Hackaday Links: May 18, 2025

May 18, 2025 by Dan Maloney 8 Comments

Say what you want about the wisdom of keeping a 50-year-old space mission going, but the dozen or so people still tasked with keeping the Voyager mission running are some major studs. That’s our conclusion anyway, after reading about the latest heroics that revived a set of thrusters on Voyager 1 that had been offline for over twenty years. The engineering aspects of this feat are interesting enough, but we’re more interested in the social engineering aspects of this exploit, which The Register goes into a bit. First of all, even though both Voyagers are long past their best-by dates, they are our only interstellar assets, and likely will be for centuries to come, or perhaps forever. Sure, the rigors of space travel and the ravages of time have slowly chipped away at what these machines can so, but while they’re still operating, they’re irreplaceable assets.

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Life On K2-18b? Don’t Get Your Hopes Up Just Yet

April 28, 2025 by Tom Nardi 27 Comments

Last week, the mainstream news was filled with headlines about K2-18b — an exoplanet some 124 light-years away from Earth that 98% of the population had never even heard about. Even astronomers weren’t aware of its existence until the Kepler Space Telescope picked it out back in 2015, just one of the more than 2,700 planets the now defunct observatory was able to identify during its storied career. But now, thanks to recent observations by the James Web Space Telescope, this obscure planet has been thrust into the limelight by the discovery of what researchers believe are the telltale signs of life in its atmosphere.

Well, maybe. As you might imagine, being able to determine if a planet has life on it from 124 light-years away isn’t exactly easy. We haven’t even been able to conclusively rule out past, or even present, life in our very own solar system, which in astronomical terms is about as far off as the end of your block.

To be fair the University of Cambridge’s Institute of Astronomy researchers, lead by Nikku Madhusudhan, aren’t claiming to have definitive proof that life exists on K2-18b. We probably won’t get undeniable proof of life on another planet until a rover literally runs over it. Rather, their paper proposes that abundant biological life, potentially some form of marine phytoplankton, is one of the strongest explanations for the concentrations of dimethyl sulfide and dimethyl disulfide that they’ve detected in the atmosphere of K2-18b.

As you might expect, there are already challenges to that conclusion. Which is of course exactly how the scientific process is supposed to work. Though the findings from Cambridge are certainly compelling, adding just a bit of context can show that things aren’t as cut and dried as we might like. There’s even an argument to be made that we wouldn’t necessarily know what the signs of extraterrestrial life would look like even if it was right in front of us.

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Hackaday Podcast Ep 318: DIY Record Lathe, 360 Degree LIDAR, And 3D Printing Innovation Lives!

April 25, 2025 by Jenny List 2 Comments

This week Elliot Williams was joined by fellow Europe-based Hackaday staffer Jenny List, to record the Hackaday Podcast as the dusk settled on a damp spring evening.

On the agenda first was robotic sport, as a set of bipedal robots competed in a Chinese half-marathon. Our new Robot overlords may have to wait a while before they are fast enough chase us meatbags away, but it demonstrated for us how such competitions can be used to advance the state of the art.

The week’s stand-out hacks included work on non-planar slicing to improve strength of 3D prints. It’s safe to say that the Cartesian 3D printer has matured as a device, but this work proves there’s plenty more in the world of 3D printing to be developed. Then there was a beautiful record cutting lathe project, far more than a toy and capable of producing good quality stereo recordings.

Meanwhile it’s always good to see the price of parts come down, and this time it’s the turn of LIDAR sensors. There’s a Raspberry Pi project capable of astounding resolution, for a price that wouldn’t have been imaginable only recently. Finally we returned to 3D printing, with an entirely printable machine, including the motors and the hot end. It’s a triumph of printed engineering, and though it’s fair to say that you won’t be using it to print anything for yourself, we expect some of the very clever techniques in use to feature in many other projects.

The week’s cant-miss articles came from Maya Posch with a reality check for lovers of physical media, and Dan Maloney with a history of x-ray detection. Listen to it all below, and you’ll find all the links at the bottom of the page.

Still mourning the death of physical media? Download an MP3 and burn it to CD like it’s 1999!

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Engraving of Alexander Graham Bell's photophone, showing the receiver and its optics

Replica Of 1880 Wireless Telephone Is All Mirrors, No Smoke

April 15, 2025 by Tyler August 18 Comments

If we asked you to name Alexander Graham Bell’s greatest invention, you would doubtless say “the telephone”; it’s probably the only one of his many, many inventions most people could bring to mind. If you asked Bell himself, though, he would tell you his greatest invention was the photophone, and if the prolific [Nick Bild] doesn’t agree he’s at least intrigued enough to produce a replica of this 1880-vintage wireless telephone. Yes, 1880. As in, only four years after the telephone was patented.

It obviously did not catch on, and is not the sort of thing that comes to mind when we think “wireless telephone”. In contrast to the RF of the 20th century version, as you might guess from the name the photophone used light– sunlight, to be specific. In the original design, the transmitter was totally passive– a tube with a mirror on one end, mounted to vibrate when someone spoke into the open end of the tube. That was it, aside from the necessary optics to focus sunlight onto said mirror. [Nick Bild] skips this and uses a laser as a handily coherent light source, which was obviously not an option in 1880. As [Nick] points out, if it was, Bell certainly would have made use of it.

Bell's selenium-based photophone receiver. — The photophone receiver, 1880 edition. Speaker not pictured.

The receiver is only slightly more complex, in that it does have electronic components– a selenium cell in the original, and in [Nick’s] case a modern photoresistor in series with a 10,000 ohm resistor. There’s also an optical difference, with [Nick] opting for a lens to focus the laser light on his photoresistor instead of the parabolic mirror of the original. In both cases vibration of the mirror at the transmitter disrupts line-of-sight with the receiver, creating an AM signal that is easily converted back into sound with an electromagnetic speaker.

The photophone never caught on, for obvious reasons — traditional copper-wire telephones worked beyond line of sight and on cloudy days–but we’re greatful to [Nick] for dredging up the history and for letting us know about it via the tip line. See his video about this project below.

The name [Nick Bild] might look familiar to regular readers. We’ve highlighted a few of his projects on Hackaday before.

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Handheld 18650 Analyzer Scopes Out Salvaged Cells

April 3, 2025 by Tom Nardi 10 Comments

You can salvage lithium 18650 cells from all sorts of modern gadgets, from disposable vapes to cordless power tools. The tricky part, other than physically liberating them from whatever they are installed in, is figuring out if they’re worth keeping or not. Just because an 18650 cell takes a charge doesn’t necessarily mean it’s any good — it could have vastly reduced capacity, or fail under heavy load.

If you’re going to take salvaging these cells seriously, you should really invest in a charger that is capable of running some capacity tests against the cell. Or if you’re a bit more adventurous, you can build this “Battery Health Monitor” designed by [DIY GUY Chris]. Although the fact that it can only accept a single cell at a time is certainly a limitation if you’ve got a lot of batteries to go though, the fact that it’s portable and only needs a USB-C connection for power means you can take it with you on your salvaging adventures.

The key to this project is a pair of chips from Texas Instruments. The BQ27441 is a “Fuel Gauge” IC, and is able to determine an 18650’s current capacity, which can be compared to the cell’s original design capacity to come up with an estimate of its overall health. The other chip, the BQ24075, keeps an eye on all the charging parameters to make sure the cell is being topped up safely and efficiently.

With these two purpose-built chips doing a lot of the heavy lifting, it only takes a relatively simple microcontroller to tie them together and provide user feedback. In this case [DIY GUY Chris] has gone with the ATmega328P, with a pair of addressable WS2812B LED bars to show the battery’s health and charge levels. As an added bonus, if you plug the device into your computer, it will output charging statistics over the serial port.

The whole project is released under the MIT license, and everything from the STL files for the 3D printed enclosure to the MCU’s Arduino-flavored firmware is provided. If you’re looking to build one yourself, you can either follow along with the step-by-step assembly instructions, or watch the build video below. Or really treat yourself and do both — you deserve it.

If your battery salvaging operation is too large for a single-cell tester, perhaps it’s time to upgrade to this 40-slot wall mounted unit.

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