DIY Induction Heater Draws 1.4 KW And Gets Metal Hot

November 29, 2020 by Lewin Day 16 Comments

Induction heaters can make conductive objects incredibly hot by generating eddy currents within the metal. They’re used in a wide variety of industrial processes, from furnaces to welders and even heat treatments. [Schematix] whipped up his own design, and put it through its paces on the bench.

The build in question is a fairly compact design, roughly shoebox-sized when fitted with its six-turn coil. Running off anything from 12 V to 48 V, the heater put out at a massive 1.4 kW in testing. At this power level, the high current draw led the power traces to heat up enough to melt solder, and eventually burn out. [Schematix] plans to rebuild the heater with added copper wiring along these traces to support the higher power levels without failure.

The heater is able to quickly heat ferrous metals, though was not able to meaningfully dump power into aluminium under testing. This is unsurprising, as non-ferrous metals primarily undergo only Joule heating from induction, forgoing the hysteresis portion of heat transfer due to being non-magnetic. However, modification to the design could improve performance for those eager to work with non-ferrous materials.

We’ve seen a few induction heaters before, for purposes as varied as soldering and casting. Video after the break.

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A Clap-Activated Machine For All Your Applause Needs

November 29, 2020 by Lewin Day 6 Comments

Applause is greatly revered as a symbol of warmth and adoration from a crowd. TV shows that film in front of a live audience often cue their audiences to clap in order to generate the desired auditory atmosphere. Of course, you don’t have to rely on squishy humans to do all the work. [Dillon] built a machine of dubious utility – one which generates mechanical applause when activated by the sound of clapping. (Video, embedded below.)

Somewhat unsurprisingly, the project was built for a Useless Machine contest, but that doesn’t diminish its value as a learning exercise. An Arduino runs the show, using a microphone module to listen out for loud noises such as claps. If two claps are detected in the nominated timeframe, the machine begins to flash its “APPLAUSE” lights and clap its hands. The Arduino achieves this with the help of a relay, which switches on a motor spinning a belt-driven cam which seperates the hands. The hands are then pulled back together to clap via a length of stretchy bungee cord.

With an incredibly noisy drivetrain and somewhat amateur clapping ability, the sound coming from the machine isn’t exactly recognisable as “applause”. However, it’s a start, and it remains the best clapping machine we’ve seen this decade. If you’ve got your own under construction, consider dropping us a line. And if all this has you waxing nostalgic for the vintage Clapper circuit, you can always build one of those, too.

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Sims-Style Plumb Bob Broadcasts Your Mood

November 28, 2020 by Kristina Panos 3 Comments

While there are a lot of objects from the Sims that we wish were real, we probably wish more than anything that everyone had a mood indicator hovering above their heads at all times. It would make working from home go a lot more smoothly, for instance. [8BitsAndAByte] made this Bluetooth-controlled plumb bob as part of their Sims Halloween costume, but we think it has real day-to-day value as this pandemic wears on, either as a mood ring or a portable free/busy indicator.

The hardware is about as simple as it gets — an Adafruit Feather nRF52 Bluefruit controls a pair of NeoPixel rings, one for each half of the translucent 3D-printed plumb bob. Power comes from a 500mAh battery, and all the electronics are situated inside of an attractive hat. Check out the build video after the break.

There’s more than one way to use color to convey information. This seven-segment temperature display does it with thermochromic film.

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TV Head Is Great Replacement For Your Real Head

November 25, 2020 by Lewin Day 19 Comments

The head is one of the few parts of the body that it seems impossible to live without. Many people are, of course, not happy with the one they’ve been given. For those dreaming of a more digital replacement, [Vivian’s] TV Head might be just the accessory to meet those needs.

The build starts with an old CRT, which [Vivian] promptly gutted to make room for her head. In place of the original tube, a thin polycarbonate sheet was installed with window tint applied. Behind this, rows of WS2812B are set up in a grid, spaced apart just enough to allow the wearer to see through. The setup is controlled by a Circuit Playground Express. A small PS/2 keyboard is used to control the light show, and the onboard accelerometer can be used for gravity reactive animations.

For some reason, screens as heads are remarkably emotive, and we kind of want one for daily wear. We can imagine it making a great Halloween costume, too. If you’ve always wanted to cosplay as one of those colorful robots from the Opening Ceremony of the 2002 World Cup, here’s your chance. You will not be surprised that this isn’t the first TV head we’ve featured. Video after the break.

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Building A Mask To Induce Lucid Dreaming

November 25, 2020 by Lewin Day 33 Comments

While dreams are generally thought of as the unconscious wanderings of the mind, that’s not the full story. Lucid dreams are ones in which the individual is conscious or semi-conscious in the dream state, and may be able to control the dream environment. Over the years, various devices have been used to generate these dream states more reliably. [Ben] decided to have a go at building his own, inspired by designs from the 1990s.

To induce lucid dreaming, the aim is to first detect that the mask wearer is in REM sleep. This is commonly done with an infrared eye tracker, which detects the rapid twitching of the eye. [Ben] used the onboard IR proximity sensor on the Adafruit Circuit Playground Express to pull this off. The accelerometer hardware was then used to detect if the wearer was still, indicating they are indeed fully asleep. Once the user is in the correct state, the mask then flashes LEDs which are intended to be visible to the wearer while dreaming. This allows them to realise they are dreaming, and thus enter a conscious, lucid state.

[Ben] doesn’t report the success rate at using the mask, but we’d love to know more about how well the mask works. We’ve seen others do similar work before, and even a recent Hackaday Prize entry. Video after the break.

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Mushroom Canoe Is Rooted In Nature

November 20, 2020 by Kristina Panos 38 Comments

Mushrooms might be the most contested pizza topping after pineapple, but can you build a boat from pineapples? Probably not, but you can from mushrooms. Mushrooms, or rather their mycelium root systems, can be used for things like packaging, insulation, and furniture, and it could be the next thing in floatation, too. Just ask [Katy Ayers], a Nebraska college student who built an eight-foot canoe molded almost entirely of mycelium.

[Katy] got into mushrooms when she was tasked with researching solutions to climate change. She loves to fish and has always wanted a boat, so when she found out that mycelium are naturally buoyant and waterproof, she decided to try using it as a building material.

[Katy] floated the idea by the owner of a local mushroom company and they got to work, building a frame suspended in the air by a hammock-like structure. Then they covered the boat’s skeleton with spores and let it proliferate in a hot, humid growing room. Two weeks later, they had a boat made of live mycelium, which means that every time it goes out on the water, it spawns mushrooms. The total cost including tools was around $500. The boat experiment spawned even more mycelium projects. [Katy] has since experimented with making lawn chairs and landscaping bricks from mycelium.

Don’t want to wait to grow your own mycelium boat? You can build one out of stretch wrap, packing tape, and tree branches.

Thanks for the tip, [ykr300]!

Main image by Katy Ayers via NBC News

Gorgeous Mini-Lathe Makes The Most Out Of Wood And Metal

November 16, 2020 by Dan Maloney 32 Comments

It’s a cliche that the only machine tool that can make copies of itself is the lathe. It’s not exactly true, but it’s a useful adage in that it points out that the ability to make big round things into smaller round things, and to make unround things into round things, is a critical process in so many precision operations. That said, making a lathe primarily out of wood presents some unique challenges in the precision department

This isn’t [Uri Tuchman]’s first foray into lathe-building. Readers may recall the quirky creator’s hybrid treadle-powered and electric lathe, also primarily an exercise in woodworking. That lathe has seen plenty of use in [Uri]’s projects, turning both wood and metal stock into parts for his builds. It wasn’t really optimal for traditional metal turning, though, so Mini-Lathe 2 was undertaken. While the bed, headstock, and tailstock “castings” are wood — gorgeously hand-detailed and finished, of course — the important bits, like the linear slides for the carriage and the bearings in the headstock, are all metal. There’s a cross-slide, a quick-change tool post, and a manual lead screw for the carriage. We love the finely detailed brass handcranks, which were made on the old lathe, and all of the lovely details [Uri] always builds into his projects.

Sadly, at the end of the video below we see that the lathe suffers from a fair amount of chatter when turning brass. That’s probably not unexpected — there’s not much substitute for sheer mass whenit comes to dampening vibration. We expect that [Uri] will be making improvements to the lathe in the coming months — he’s not exactly one to leave a job unfinished.

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