For Americans Only: Estimating Celsius And Other Mental Metrics

August 14, 2025 by 192 Comments

I know many computer languages, but I’ve struggled all my life to learn a second human language. One of my problems is that I can’t stop trying to translate in my head. Just like Morse code, you need to understand things directly, not translate. But you have to start somewhere. One of the reasons metric never caught on in the United States is that it is hard to do exact translations while you are developing intuition about just how hot is 35 °C or how long 8 cm is.

If you travel, temperature is especially annoying. When the local news tells you the temperature is going to be 28, it is hard to do the math in your head to decide if you need a coat or shorts.

Ok, you are a math whiz. And you have a phone with a calculator and, probably, a voice assistant. So you can do the right math, which is (9/5) x °C + 32. But for those of us who can’t do that in our heads, there is an easier way.

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3D Printing A Self-cleaning Water Filter

August 14, 2025 by 22 Comments

No one likes cleaning out water spouts. [NeedItMakeIt] wanted to collect rainwater and was interested in using a Coanda filter that those used on hydroelectric plants to separate out debris. Ultimately, he decided to design his own and 3D print it.

The design uses a sloping surface with teeth on it to coax water to go in one direction and debris to go in another. It fits into a typical spout, and seems like it works well enough. Some commenters note that varying volumes of rain and different types of debris behave differently, which is probably true. However, there are similar commercial products, so you’d guess there would be some value to using the technique.

The water pushes the debris off the slope, so you end up losing a little water with the debris. So as always, there’s a trade-off. You can see in the video that if the water flow isn’t substantial, the debris tends to stall on the slope. Could the filter be improved? That was the point in trying a second design.

It wasn’t a big improvement. That’s where there’s a plot twist. Well, actually, a literal twist. Instead of making a flat slope, the new design is a conic shape with a spiral channel. That improved flow quite a bit. We weren’t clear from the video of exactly where the debris was going with the last version.

Usually, when we think of the Coanda effect, we are thinking aerodynamics. It can be quite uplifting.

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How The Widget Revolutionized Canned Beer

August 14, 2025 by 76 Comments

Walk into any pub and order a pint of Guinness, and you’ll witness a mesmerizing ritual. The bartender pulls the tap, fills the glass two-thirds full, then sets it aside to settle before topping it off with that iconic creamy head. But crack open a can of Guinness at home, and something magical happens without any theatrical waiting period. Pour it out, and you get that same cascading foam effect that made the beer famous.

But how is it done? It’s all thanks to a tiny little device that is affectionately known as The Widget.

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Hacking The Bluetooth-Enabled Anker Prime Power Bank

August 14, 2025 by 35 Comments

Selling power banks these days isn’t easy, as you can only stretch the reasonable limits of capacity and output wattage so far. Fortunately there is now a new game in town, with ‘smart’ power banks, like the Anker one that [Aaron Christophel] recently purchased for reverse-engineering. It features Bluetooth (BLE), a ‘smart app’ and a rather fancy screen on the front with quite a bit of information. This also means that there’s a lot to hack here beyond basic battery management system (BMS) features.

As detailed on the GitHub project page, after you get past the glue-and-plastic-clip top, you will find inside a PCB with a GD32F303 MCU, a Telink TLSR8253 BLE IC and the 240×240 ST7789 LCD in addition to a few other ICs to handle BMS functions, RTC and such. Before firmware version 1.6.2 you can simply overwrite the firmware, but Anker added a signature check to later firmware updates.

The BLE feature is used to communicate with the Anker app, which the official product page advertises as being good for real-time stats, smart charging and finding the power bank by making a loud noise. [Aaron] already reverse-engineered the protocol and offers his own alternative on the project page. Naturally updating the firmware is usually also done via BLE.

Although the BLE and mobile app feature is decidedly a gimmick, hacking it could allow for some interesting UPS-like and other features. We just hope that battery safety features aren’t defined solely in software, lest these power banks can be compromised with a nefarious or improper firmware update.

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Steampunk Copper PC Is As Cool As It Runs

August 14, 2025 by 26 Comments

Copper! The only thing it does better than conduct heat is conduct a great steampunk vibe. [Billet Labs]’ latest video is an artfully done wall PC that makes full use of both of those properties.

The parts are what you’d expect in a high-end workstation PC: a Ryzen 9 and an 3090Ti with oodles of RAM. It’s the cooling loop where all the magic happens: from the copper block on the CPU, to the plumbing fixtures that give the whole thing a beautiful brewery-chiq shine when polished up. Hopefully the water-block in the GPU is equally cupriferous too, but given the attention to detail in the rest of the build, we cannot imagine [Billet Labs] making such a rookie mistake as to invite Mr. Galvanic Corrosion to the party.

There’s almost no visible plastic or paint; the GPU and PSU are hidden by a brass plates, and even the back panel everything mounts to is shiny metal. Even the fans on the radiator are metal, and customized to look like a quad throttle body or four-barreled carburetor on an old race car. (Though they sound more like a jet takeoff.)

The analog gauges are a particular treat, which push this build firmly into “steampunk” territory. Unfortunately the temperature gauge glued onto the GPU only measures the external temperature of the GPU, not the temperature at the die or even the water-block. On the other hand, given how well this cooling setup seems to work later in the video, GPU temps are likely to stay pretty stable. The other gauges do exactly what you’d expect, measuring the pressure and temperature of the water in the coolant loop and voltage on the twelve volt rail.

Honestly, once it gets mounted on the wall, this build looks more like an art piece than any kind of computer— only the power and I/O cables do anything to give the game away. Now that he has the case, perhaps some artful peripherals are in order?

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Flyback Converter Revealed

August 13, 2025 by 10 Comments

As [Sam Ben-Yaakov] points out in a recent video, you don’t often see flyback converters these days. That’s because there are smarter ways to get the same effect, which is to convert between two voltages. If you work on old gear, you’ll see plenty of these, and going through the analysis is educational, even if you’ll never actually work with the circuit. That’s what the video below shows: [Sam’s] analysis of why this circuit works.

The circuit in question uses a bridge rectifier to get a high-voltage DC voltage directly from the wall. Of course,  you could just use a transformer to convert the AC to a lower AC voltage first, but then you probably need a regulator afterwards to get a stable voltage.

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2025 One Hertz Challenge: Digital Clock Built With Analog Timer

August 13, 2025 by 1 Comment

You can use a microcontroller to build a clock. After all, a clock is just something that counts the passage of time. The only problem is that microcontrollers can’t track time very accurately. They need some kind of external timing source that doesn’t drift as much as the microcontroller’s primary clock oscillator. To that end, [Josh] wanted to try using a rather famous IC with his Arduino to build a viable timepiece.

[Josh]’s idea was straightforward—employ a 555 timer IC to generate a square wave at 1 Hz. He set up an Arduino Uno to count the pulses using edge detection. This allowed for a reliable count which would serve as the timebase for a simple 24-hour clock. The time was then displayed on an OLED display attached over I2C, while raw pulses from the 555 were counted on a 7-segment display as a useful debugging measure. Setting the time is easy, with a few pushbuttons hooked up to the Arduino for this purpose.

[Josh] claims a drift of “only ~0.5 seconds” but does not state over what time period this drift occurs. In any case, 555s are not really used for timekeeping purposes in this way, because timers based on resistor-capacitor circuits tend to drift a lot and are highly susceptible to temperature changes. However, [Josh] could easily turn this into a highly accurate clock merely by replacing the 555 square wave input with a 1PPS clock source from another type of timer or GPS device.

We’ve had quite a few clocks entered into the One Hertz Competition already, including this hilariously easy Nixie clock build. You’ve got until August 19 to get your own entry in, so wow us with your project that does something once a second!

2025 Hackaday One Hertz Challenge