You Gotta Want It

August 22, 2026 by Elliot Williams No comments

On Hackaday last week, and on the podcast, we were talking about one of the educational toys of yesteryear that launched a thousand careers, at least if the comment section is to be believed: the Radio Shack 200-in-1 electronics kit. The “toy” itself was basically a bunch of components with spring terminals, but the secret sauce was in in the instruction book, and maybe the marketing.

Tom had one of these when he was a kid, and told a great story about wanting it desperately based on the ads he had seen with kids Morse coding to each other. When he got the kit, and found out that “it was just a bunch of wires” he was fully pissed off. But he worked through the examples, learned some basic electronics, and the rest is history.

What I really love about this story is the siren’s call of a good project. Tom was pulled in, and maybe even fooled, by the advertising, but it probably changed his life. It’s funny how many of our folks can remember the first project that got them hooked as well. With me it was some simple audio effects pedals and then maybe later some simple BEAM robots, and for younger hackers maybe it was a 3D printer or Arduino project.

Digital or analog, the common ground here is that we all thought that some project was cool enough to warrant the sweat of learning enough to do it. Good instructions are helpful of course, and having the parts on hand never hurts. But it’s the promise of making something that you really want that I think underlies all good first projects. (And heck, every subsequent project as well.)

So while Tom, and a bunch of our readers, were looking back with nostalgia at the 200-in-1, I’m thinking about how many more than 200 projects I’ve seen made by our community, and even featured here on Hackaday, that are out there to provide the motivation to get someone started. Keep on hacking!

Building An Analog Geiger Counter

August 22, 2026 by Zoe Skyforest No comments

These days, it’s plenty easy to build a Geiger counter with a microcontroller that has a nice fancy display and a simple digital readout for how many radiations you’re likely sucking up into your delicate fleshy body. But you can still do things the old fashioned way, as [ludens] demonstrates with this analog Geiger counter project.

With a goal of measuring low-level radiation sources and the normal background levels on Earth, [ludens] selected a large Geiger tube for its sensitivity—a Chinese J306β in particular. It’s rated to output 88 counts per minute at the average background level, or 8 counts per second when exposed to 1µSv/h. It’s quite a large device, measuring 200 mm long and 18 mm in diameter, and it sticks out on top of the device like a big fat antenna.

Since the large tube puts out plenty of counts at even low levels, [ludens] decided it would be easy to average the output with a simple analog low-pass circuit. Everything runs off a single AA battery, with a power supply built to step that up to 5 V for the ICs and 400 V for the tube itself. CMOS Schmitt triggers are responsible for running the show, with an old-school analog dial showing the reading.

There are two ranges to use, depending on the magnitude of the radiation source—1 uSv/h, and 10 uSv/h. The high range isn’t particularly high, but as [ludens] notes—”If anything I find pegs that scale, I prefer to run, instead of measuring exactly how much radiation there is! So I don’t need a higher scale than 10µSv/h.”

If you’ve ever wanted to build a Geiger counter that has that classic Cold War feel, this is a great way to go about it. Alternatively, you can always go the more modern route and build something digital and networkable for logging purposes.

Brown wrapped chrome handlebars leaning against a light grey wall. Near the stem, a series of four small pins protrude from the bars to indicate a full battery charge of 100%.

Sleeper E-bike Has Solenoid Display

August 22, 2026 by Navarre Bartz 6 Comments

[GRMNT] decided to bring his grandpa’s beautiful road bike into the future by making a sleeper e-bike conversion.

Going into the project, [GRMNT] didn’t really know what he was working with, but it turned out grandpa had good taste and was rocking a Bianchi. No stovepipe bike boom stuff here, only high quality Tange steel. After cleaning off the years of grime, it was time to rebuild a second-hand Bafang mid-drive electric motor for the electric boost for the ride.

We really like the custom solenoid-powered display that [GRMNT] built into the handlebars for an excellent electromechanical readout of the battery charge. Coupled with the hand-built battery pack inside a leather case and hidden motor actuation button, this build looks slick without screaming e-bike.

We’ve covered some other conversions in the past including this one using an electric skateboard motor or this plug-and-play kit. If you’d rather power things with your bike, you’ll like this hack that can make everything bike powered.

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Hacking A Cat Litter Box

August 21, 2026 by Zoe Skyforest 11 Comments

[Joseph DiGiovanni] is the owner of a Litter Robot 4. It’s a convenient mechanized litter box for cats that can clean itself to reduce unwelcome odors inside the home. He wanted to run automations based on the operation of the litter box, but was not eager to use the manufacturer’s cloud service to do it. Instead, he set about reverse engineering the device for his own ends.

Since the Litter Robot 4 relies on an ESP32 microcontroller for external connectivity, it was entirely possible for [Joseph] to whip up a custom firmware for the device instead. He started with ESPHome as a base, which is a popular firmware used for building smarthome devices based on Espressif hardware. The architecture of the Litter Robot 4 helped in this regard. It uses a PIC microcontroller to handle the low level hardware control, while the ESP32 is responsible for connecting to the cloud over WiFi. This allowed [Joseph] to mess with the connectivity features and get the device hooked up to Home Assistant without compromising the basic mechancial functionality of the device or any of the safety features.

All [Joseph] had to do was figure out how the original hardware’s ESP32 talked to the PIC and emulate that in his own firmware, which was achieved with some snooping and data capture and processing with an LLM. This was used as a basis to whip up an ESPHome firmware that could integrate the hardware neatly with Home Assistant.

Files are on Codeberg for those eager to tinker. It’s not the first time we’ve looked at cat litter management, and it won’t be the last. Video after the break.

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How The Grid’s Harmonic Filters Keep The Power Clean

August 21, 2026 by Maya Posch 2 Comments

A fun way to think about a national electrical grid is as a massively upscaled electrical circuit, one in which you have multiple power supplies injecting AC power, with various bits and bobs involving resistors, inductors and capacitors in between working to synchronize and clean-up this power before it gets to the end users. Recently [Jordan Taylor], also known as [The Electric Brit] took a look at the grid’s harmonic filters that do a lot of this sinewave scrubbing after the HVDC to AC conversion.

Using a UK-based line-commutated converter (LCC) HVDC converter station as a physical example [Jordan] takes us through the elements of this harmonic filter, what it is, what it does and why it’s a necessity. The design considerations with components at this immense scale are also covered, along with the types of filters possible.

The Cliff’s Notes version is that following the conversion step from said HVDC there are harmonics introduced in the AC, not unlike in a much lower-voltage converter. This results in a noisy sinewave that can potentially cause harm to AC-powered devices, not to mention cause heating and other losses along the way. The answer is naturally to add an LC-filter, just on a slightly larger scale than for consumer electronics.

Also noted by [Jordan] is the nice synergy of these harmonic filters when it comes to absorbing and generating reactive power on the AC grid, due to their massive capacitors and inductors. This helps to dampen oscillations on the grid and thus further contributing to its stability.

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Building A Hammond Organ To Understand How They Work

August 21, 2026 by Tyler August 13 Comments

The Hammond organ is an early form of electronic– or perhaps electromechanical– musical instrument. It solved the very real problem of organs normally being the sort of thing you built into a cathedral, allowing a similar sound to fit into a piano-like form factor. Their workings are a so simple that it’s hard to wrap your head around it actually working– which is why [Uri Tuchman] built one on YouTube. Also for a gift exchange, but we’re not Santa, here– we’re here to learn, and [Uri] does not disappoint.

[Uri]’s organ is a bit smaller than what the Hammond corporation was putting out back in the day, just one hand-cranked octave– and it lacks the distinct spinning speaker in favour of plugging into any old guitar amp. It’s enough to get the idea across. Each of the twelve keys acts as a simple switch, wired to a pickup made from a coil of wire around a steel rod– much like a magnetic pickup on an electric guitar. The pickup faces the tone wheel, which is the part that feels like magic: the tonewheel spinning past the pickup acts exactly like the steel string vibrating in an electric guitar, its ferroelectric motions inducing a tiny current. The tonewheels smooth teeth are spaced to create sine waves at the frequencies corresponding to each key, so it has to be exact. That’s why while the rest of the brass-and-wood build is [Uri]’s beautiful craftsmanship, the iron tonewheels are CNC’d.

Aside from the amp it is plugged into, there are no electronics here. There’s nothing to double or otherwise alter the frequencies: one key means one tonewheel– twelve for this build– and if the RPMs are off everything is out of tune. Good thing [Uri] made it hand-cranked! Well, it is for a gift exchange. Maybe it’s a white elephant sort of thing, because we can only imagine that making it much harder to play. On the other hand, [Uri] demonstrates some neat effects by varying the RPM at the end of the video, so perhaps that’s a feature.

As nice as [Uri]’s work is, Hammond Organ Company filmed the construction themselves, back in the day if you want to see the true quill. Alternatively, you can get more of [Uri]’s craftsmanship with this square guitar.

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Thermoacoustic Sterling Engine Is Now Fully 3D Printable

August 21, 2026 by Tyler August 16 Comments

Would you like to make your own energy? Why, who doesn’t in this era of rising costs! A sterling engine always looks like a good fit for that: highly efficient, with no risk of a boiler explosion. A thermoacoustic sterling engine looks even better, since it has only one moving part at the output end. A thermoacoustic sterling engine you can 3D print yourself looks best of all, and that’s what [my engines] has on offer, now that even the burner and hot end of his thermoacoustic engine are designed for SLA metal printing.

We previously reported on the open-source engine, but there’ve been some improvements worth talking about. For one thing, he’s integrated a biogas/methane burner directly inside the 3D-printable hotend. For another, that 3D-printed design allows for an excellent heat exchange geometry that would be very hard to get any other way. The whole thing is open source with plans available at OwnEnergy.org, where you can find links to the apparently-mandatory Discord channel and now an old-style forum to actually collaborate on the design, which is open-source. The site is also now the home of all data and discussion about [my engines]’s homescale biogas plant, which is the power source for this little engine.

If you’d rather print a combustion engine, you can do that, too, but you’ll need more “vitamins” than this unit requires.

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