A photo of a the power supply, distribution board, and primary and secondary windings on a bench top.

Bench-Top Wireless Power Transmission

August 14, 2025 by 8 Comments

[mircemk] has been working on wireless power transmission. Using a Class-E Tesla coil with 12 turns on the primary and 8 turns on the secondary and a 12 volt input he can send a few milliwatts to power an LED over a distance of more than 40 centimeters or power a 10 watt bulb over a distance of about 10 centimeters. With the DC input set at 24 volts the apparatus can deliver 5 watts over a distance of a few centimeters and a light is still visible after separating the primary and secondary coils by more than 30 centimeters.

There are many types of Tesla coil and we can’t go into the details here but they include Spark-Gap Tesla Coils (SGTC) and Solid-State Tesla Coils (SSTC), among others. The Class-E coil demonstrated in this project is a type of SSTC which in general is more efficient than an SGTC alternative.

Please bear in mind that while it is perfectly safe to watch a YouTube video of a person demonstrating a functional Tesla coil, building your own is hazardous and probably not a good idea unless you really understand what you’re doing! Particularly high voltages can be involved and EMI/RFI emissions can violate regulations. You can damage your body with RF burns while not feeling any pain, and without even knowing that it’s happening.

If you’d like to read more about wireless power transmission it is certainly a topic we’ve covered here at Hackaday in the past, you might like to check out Wireless Power Makes For Cable-Free Desk or Transmitting Wireless Power Over Longer Distances.

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DIY Wind Turbine Gets A 3-Phase Rectifier

August 14, 2025 by 18 Comments

[Electronoobs] is using some brushless motors to make a DIY wind turbine. His recent video isn’t about the turbine itself, but a crucial electronic part: the three-phase rectifier. The reason it is so important is due to the use of brushless motors. Normal motors are not ideal for generating power for several reasons, as explained in the video below.

The brushless motors have three windings and generate three outputs, each out of phase with the others. You can’t just join them together because they are 120 degrees out of phase. But a special rectifier can merge the inputs efficiently and output a low-ripple DC voltage.

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2025 One Hertz Challenge: Blinking An LED With The Aid Of Radio Time

August 14, 2025 by 3 Comments

If you want to blink an LED once every second, you could use just about any old timer circuit to create a 1 Hz signal. Or, you could go the complicated route like [Anthony Vincz] and grab 1 Hz off a radio clock instead. 

The build is an entry for the 2025 One Hertz Challenge, with [Anthony] pushing himself to whip up a simple entry on a single Sunday morning. He started by grabbing a NE567 tone decoder IC, which uses a phase-locked loop to trigger an output when detecting a tone of a given frequency. [Anthony] had used this chip hooked up to an Arduino to act as a Morse decoder, which picked up sound from an electret mic and decoded it into readable output.

However, he realized he could repurpose the NE567 to blink in response to output from radio time stations like the 60 KHz British and 77.5 KHz German broadcasts. He thus grabbed a software-defined radio, tuned it into one of the time stations, and adjusted the signal to effectively sound a regular 800 Hz tone coming out of his computer’s speakers that cycled once every second. He then tweaked the NE567 so it would trigger off this repetitive tone every second, flashing an LED.

Is it the easiest way to flash an LED? No. It’s complicated, but it’s also creative. They say a one hertz signal is always in the last place you look.

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For Americans Only: Estimating Celsius And Other Mental Metrics

August 14, 2025 by 194 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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