When building a new project, common wisdom suggests to avoid “reinventing the wheel”, or doing something simple from scratch that’s easily available already. However, if you can build a high-voltage wheel, so to speak, it might be fun just to see what happens. [Dan] decided to reinvent not the wheel, but the speaker, and instead of any conventional build he decided to make one with parts from a microwave and over 6,000 volts.
The circuit he constructed works essentially like a Tesla coil with a modulated audio signal as an input. The build uses the high voltage transformer from the microwave too, which steps the 240 V input up to around 6 kV. To modulate that kind of voltage, [Dan] sends the audio signal through a GU81M vacuum tube with the support of a fleet of high voltage capacitors. The antenna connected to the magnetron does tend to catch on fire somewhere in the middle of each song, so it’s not the safest device around even if the high voltage can be handled properly, but it does work better than expected as a speaker.
If you want a high-voltage speaker that (probably) won’t burn your house down, though, it might be best to stick to a typical Tesla coil. No promises though, since working with high voltages typically doesn’t come with safety guarantees.
Continue reading “Swap Your Microwave For A High Voltage Stereo”
Despite their dangers, even Marie Kondo would not convince us to abandon flamethrower projects because they literally spark joy in us. To make this flame shooting Aladdin lamp [YeleLabs] just used a 3D printer and some basic electronics.
The lamp body consists of two 3D-printed halves held together by neodymium magnets. They house a 400 kV spark generator, a fuel pump plus tank, and a 18650 Li-ion battery. The fuel pump is actually a 3 V air pump but it can also pump liquids at low pressure. As fuel [YeleLabs] used rubbing alcohol that they mixed with boric acid to give the flame a greenish tint. The blue base at the bottom of the lamp houses the triggering mechanism which magically lights up the lamp when you snap your fingers. This is achieved by a KY-038 microphone module and KY-019 relay module connected to a Digispark ATTiny85 microcontroller. When the microphone signal is above a certain threshold the relay module will simultaneously switch on the spark generator and fuel pump for 150 ms.
Although they proclaim that the device is a hand sanitizer it is probably safer to stick to using soap. The project still goes on the list of cool flamethrower props right next to the flame shooting Jack-o-Lantern.
Video after the break.
Continue reading “Aladdin Lamp Shoots Flames With A Snap Of Your Fingers”
Fair warning: any homeowners who have thermostats similar to the one that nearly burned down [Kerry Wong]’s house might be in store for a sleepless night or two, at least until they inspect and perhaps replace any units that are even remotely as sketchy as what he found when he did the postmortem analysis in the brief video below.
The story begins back in the 1980s, when the Southern New England area where [Kerry] lives enjoyed a housing boom. Contractors rushed to turn rural farmland into subdivisions, and new suburbs crawled across the landscape. Corners were inevitably cut during construction, and one common place to save money was the home’s heating system. Rather than engage an HVAC subcontractor to install a complicated heating system, many builders opted instead to have the electricians install electric baseboards. They were already on the job anyway, and at the time, both copper and electricity were cheap.
Fast forward 40 years or so, and [Kerry] finds himself living in one such house. The other night, upon catching the acrid scent of burning insulation, he followed his nose to the source: a wall-mounted thermostat for his electric baseboard. His teardown revealed burned insulation, bare conductors, and scorched plastic on the not-so-old unit; bearing a 2008 date code, the thermostat must have replaced one of the originals. [Kerry] poked at the nearly combusted unit and found the root cause: the spot welds holding the wires to the thermostat terminal had become loose, increasing the resistance of the connection. As [Kerry] points out, even a tenth of an ohm increase in resistance in a 15 amp circuit would dissipate 20 watts of heat, and from the toasty look of the thermostat it had been a lot more than that.
The corner-cutting of the 1980s was nothing new, of course – remember the aluminum wiring debacle? Electrical fires are no joke, and we’re glad [Kerry] was quick to locate the problem and prevent it from spreading.
Continue reading “Fail Of The Week: Thermostat Almost Causes A House Fire”
It seems like hardly a day goes by that doesn’t see some news story splashed across our feeds that has something to do with Elon Musk and one or another of his myriad companies. The news is often spectacular and the coverage deservedly laudatory, as when Space X nails another double landing of its boosters after a successful trip to space. But all too often, it’s Elon’s baby Tesla that makes headlines, and usually of the kind that gives media relations people ulcers.
The PR team on the automotive side of Tesla can take a bit of a breather now, though. This time it’s Elon’s solar power venture, Tesla Energy Operations, that’s taking the heat. Literally — they’ve been sued by Walmart for rooftop solar installations that have burst into flames atop several of the retail giant’s stores. While thankfully no lives have been lost and no major injuries were reported, Walmart is understandably miffed at the turn of events, leading to the litigation.
Walmart isn’t alone in their exposure to potential Tesla solar problems, so it’s worth a look to see what exactly happened with these installations, why they failed, and what we as hackers can learn from the situation. As we’ll see, it all boils down to taking electrical work very seriously and adhering to standards designed to keep everyone safe, even when they just seem like a nuisance.
Continue reading “Solar System Wars: Walmart Versus Tesla”
Imagine if you will that you are enthroned upon the porcelain, minding your own business while doing your business. You’re catching up on Hackaday on your phone – c’mon, admit it – when a whir and a buzz comes from behind you. You sit up in alarm, whereupon your lower back suddenly feels as if someone is scrubbing it with a steel wool pad. Then the real pain sets in as super-hot plasma lances into your skin, the smell of burning flesh fills the bathroom, and you crack your head on the towel bar trying to escape this torture chamber in a panic.
Sound good? Then [Vije Miller]’s plasma-powered toilet air freshener is a must-build for you. We’re not entirely sure where this was going, but the name of the project seems to indicate a desire to, ahem, clear the air near your derrière with the power of ions. While that might work – we’ve recently seen an electrostatic precipitator for 3D-printer fumes – the implementation here is a bit sketchy. The ball of steel wool? It was possibly intended as a way to disperse the ions, but it served as nothing more than fuel when touched by the plasma. The Contact-esque gimballed rings? Not a clue what they’re for, but they look cool. And hats off to [Vije] for the intricate 3D-printed parts, the geartrain and linkages, and the DIY slip rings.
It may be a head-scratcher of a build, but the video below is entertaining. Check out some of [Vije]’s other projects of dubious value, like his licorice launcher or the smartphone back scratcher.
Continue reading “Fail Of The Week: Toilets And High Voltage Do Not Mix”
While we’re certainly not denying that smoke detectors are useful, there’s a certain kind of tragedy to the fact that most of them will never realize their true purpose of detecting smoke, and alerting us to a dangerous fire. On the other hand, [Ben] really unlocks the potential hidden deep in every smoke detector with his latest project which uses the smoke-detecting parts of a smoke detector to turn on the exhaust fan over his stove.
The project didn’t start with the noble aim of realizing the hidden and underutilized quiescent nature of a smoke alarm, though. He wanted his range exhaust fan to turn on automatically when it was needed during his (and his family’s) cooking activities. The particular range has four speeds so he wired up four relays to each of the switches in the range and programmed a Particle Photon to turn them on based on readings from an MQ-2 gas-detecting sensor.
The sensor didn’t work as well as he had hoped. It was overly sensitive to some gasses like LPG which would turn the range on full blast any time he used his cooking spray. Meanwhile, it would drift and not work properly during normal cooking. He tried disabling it and using only a temperature sensor, which didn’t work well either. Finally, he got the idea to tear apart a smoke detector and use its sensor’s analog output to inform the microcontroller of the current need for an exhaust fan. Now that that’s done, [Ben] might want to add some additional safety features to his stovetop too.
You know the funny looking side of the anvil? That’s where the best curves come from. It’s called the anvil horn and is the blacksmith’s friend when bending steel and shaping it into curves.
The principle of bending a piece of steel stock is very easy to understand. Heat it up to temperature, and hammer it over a curved profile to the intended shape. A gentler touch is required than when you are shaping metal. That’s because the intent is to bend the metal rather than deform. Let’s take a look!
Continue reading “Blacksmithing For The Uninitiated: Curves And Rings”