Using A Level 2 Charger To Work Around Slow 120 VAC Kettles

December 1, 2025 by 52 Comments

To those of us who live in the civilized lands where ~230 VAC mains is the norm and we can shove a cool 3.5 kW into an electric kettle without so much as a second thought, the mere idea of trying to boil water with 120 VAC and a tepid 1.5 kW brings back traumatic memories of trying to boil water with a 12 VDC kettle while out camping. Naturally, in a fit of nationalistic pride this leads certain North American people like that bloke over at the [Technology Connections] YouTube to insist that this is fine, as he tries to demonstrate how ridiculous 240 VAC kettles are by abusing a North American Level 2 car charger to power a UK-sourced kettle.

Ignoring for a moment that in Europe a ‘Level 1’ charger is already 230 VAC (±10%) and many of us charge EVs at home with three-phase ~440 VAC, this video is an interesting demonstration, both of how to abuse an EV car charger for other applications and how great having hot water for tea that much faster is.

Friendly tea-related transatlantic jabs aside, the socket adapter required to go from the car charger to the UK-style plug is a sight to behold. All which we starts as we learn that Leviton makes a UK-style outlet for US-style junction boxes, due to Gulf States using this combination. This is subsequently wired to the pins of the EV charger connector, after which the tests can commence.

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Quiet Your Drums With An Electronic Setup

December 1, 2025 by 7 Comments

Playing the drums requires a lot of practice, but that practice can be incredibly loud. A nice workaround is presented by [PocketBoy], in converting an acoustic kit to electronic operation so you can play with headphones instead.

A sensor installed inside a floor tom.

It might sound like a complicated project, but creating a basic set of electronic drums can actually be quite simple if you’ve already got an acoustic kit. You just need to damp all the drums and cymbals to make them quieter, and then fit all the individual elements with their own piezo sensors. These are basically small discs that can pick up vibrations and turn them into electricity—which can be used to trigger an electronic drum module.

[PocketBoy]’s build started with a PDP New Yorker kit, some mesh heads to dull the snares and toms, and some low-volume cymbals sourced off Amazon. Each drum got a small piezo element, which was soldered to a 6.5mm jack for easy hookup. They’re installed inside the drums on foam squares with a simple bracket system [PocketBoy] whipped up from hardware store parts. A DDrum DDti interface picks up the signals from the piezo elements and sends commands to an attached PC. It’s paired with Ableton 12 Lite, which plays the drum sounds as triggered by the drummer.

[PocketBoy] notes it’s a quick and dirty setup, good for quiet practice but not quite gig-ready. You’d want to probably just run it as a regular acoustic kit in that context, but there’s nothing about the conversion that prevents that. Ultimately, it’s a useful project if you find yourself needing to practice the drums quietly and you don’t have space for a second electric-only kit. There’s lots of other fun you can have with those piezos, too. Video after the break.

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Australia’s New Asbestos Scare In Schools

December 1, 2025 by 47 Comments

Asbestos is a nasty old mineral. It’s known for releasing fine, microscopic fibers that can lodge in the body’s tissues and cause deadly disease over a period of decades. Originally prized for its fire resistance and insulating properties, it was widely used in all sorts of building materials. Years after the dangers became clear, many countries eventually banned its use, with strict rules around disposal to protect the public from the risk it poses to health.

Australia is one of the stricter countries when it comes to asbestos, taking great pains to limit its use and its entry into the country. This made it all the more surprising when it became apparent that schools across the nation had been contaminated with loose asbestos material. The culprit was something altogether unexpected, too—in the form of tiny little tubes of colored sand. Authorities have rushed to shut down schools as the media asked the obvious question—how could this be allowed to happen?

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How To Design 3D Printed Pins That Won’t Break

December 1, 2025 by 8 Comments

[Slant 3D] has a useful video explaining some thoughtful CAD techniques for designing 3D printed pins that don’t break and the concepts can be extended to similar features.

Sure, one can make pins stronger simply by upping infill density or increasing the number of perimeters, but those depend on having access to the slicer settings. If someone else is printing a part, that part’s designer has no actual control over these things. So how can one ensure sturdier pins without relying on specific print settings? [Slant 3D] covers two approaches.

The first approach includes making a pin thick, making it short (less leverage for stress), and adding a fillet to the sharp corner where the pin meets the rest of the part. Why? Because a rounded corner spreads stress out, compared to a sharp corner.

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3D Printing And The Dream Of Affordable Prosthetics

December 1, 2025 by 7 Comments

As amazing as the human body is, it’s unfortunately not as amazing as e.g. axolotl bodies are, in the sense that they can regrow entire limbs and more. This has left us humans with the necessity to craft artificial replacement limbs to restore some semblance of the original functionality, at least until regenerative medicine reaches maturity.

Despite this limitation, humans have become very adept at crafting prosthetic limbs, starting with fairly basic prosthetics to fully articulated and beautifully sculpted ones, all the way to modern-day functional prosthetics. Yet as was the case a hundred years ago, today’s prosthetics are anything but cheap. This is mostly due to the customization  required as no person’s injury is the same.

When the era of 3D printing arrived earlier this century, it was regularly claimed that this would make cheap, fully custom prosthetics a reality. Unfortunately this hasn’t happened, for a variety of reasons. This raises the question of whether 3D printing can at all play a significant role in making prosthetics more affordable, comfortable or functional.

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The New Pebble: Now 100% Open Source

December 1, 2025 by 12 Comments

The Pebble was the smartwatch darling of the early 2010s, a glimpse of the future in the form of a microcontroller and screen strapped to your wrist. It was snapped up by Fitbit and canned, which might have been the end of it all were it not for the dedication of the Pebble community. Google open-sourced the OS back in January this year, and since then a new set of Pebble products have appeared under the guidance of Pebble creator [Eric Migicovsky]. Now he’s announced the full open-sourcing of the current Pebble hardware and software stack. As he puts it, “Yesterday, Pebble watch software was ~95% open source. Today, it’s 100% open source”.

If you’re curious it can all be found in repositories under the Core Devices GitHub account. Building your own Pebble clone sounds cool, but perhaps the real value lies instead in giving the new Pebbles something the original never had, an assured future. If you buy one of the new watches then you’ll know that it will remain fixable, and since you have the full set of files you can create new parts for it, or update its software. We think that’s the right way to keep a personal electronic device relevant.

If you want a new Pebble they have a store, meanwhile read some of our previous coverage of its launch.

Sensor Package Aims To Predict Acid Rain

December 1, 2025 by 5 Comments

Acid rain sucks, particularly if you run a fancy university with lots of lovely statues outside. If you’d like to try and predict when it’s going to occur, you might like this project from [Mohammad Nihal].

When rain is particularly acidic, it’s usually because of the combination of sulfur dioxide or nitrogen dioxide and moisture in the atmosphere. This combination ends up making sulfuric acid or nitric acid that then falls to the ground as precipitation. The low-pH rain that results can harm ecosystems, melt statues, and just generally give everyone a hard time.

[Mohammed] decided to try and predict acid rain by building a simple device based on an Arduino Nano. It records SO2 levels with an MQ-136 gas sensor, and NO2 levels with an unspecified MEMS-based sensor. There’s also a DHT11 temperature & humidity sensor in the mix, which is important since moisture content plays a role. The Arduino reads these sensors and uses a simple predictive algorithm to create an “Acid Rain Risk Score” that is displayed on a 16×2 character LCD. It’s all wrapped up in a fun 3D printed enclosure that looks like a cloud.

There are some limitations to the device. Namely, it doesn’t necessarily have a great read on atmospheric SO2 and NO2 levels in the atmosphere, particularly at altitudes where rain is formed, because the sensor sits inside the device indoors. However, the basic concept is there, and improvements could certainly be made with some upgrades and further research.