Émilie du Châtelet: An Energetic Life

Émilie du Châtelet lived a wild, wild life. She was a brilliant polymath who made important contributions to the Enlightenment, including adding a mathematical statement of conservation of energy into her French translation of Newton’s Principia, debunking the phlogiston theory of fire, and suggesting that what we would call infrared light carried heat.

She had good company; she was Voltaire’s lover and companion for fifteen years, and she built a private research institution out of a château with him before falling in love with a younger poet. She was tutored in math by Maupertuis and corresponded with Bernoulli and Euler. She was an avid gambler and handy with a sword. She died early, at 41 years, but those years that she did live were pretty amazing. Continue reading “Émilie du Châtelet: An Energetic Life”

Fire. Vortex. Cannon. Need We Say More?

Tornadoes are a rightfully feared natural disaster. Fire tornadoes are an especially odious event to contend with — on top of whatever else is burning. But, a fire vortex cannon? That’s some awesome eye candy.

The madman behind this cannon belching huge gouts of fire is none other than Youtuber [JAIRUS OF ALL]. This build is actually an upgrade to one of his previous projects — a fire tornado gun that burned itself out and is now twice-revived — and is arguably better at creating a proper vortex to direct the flames. Built around a modified NERF gun, a pair of 60mm electric ducted fans with some additional venting — and tunable via a speed controller — direct the airflow through slits in a vortex chamber. A backpack of liquid propane literally fuels this phoenix of a flamethrower, so [JAIRUS] had plenty of time to put together some great footage. Check it out!

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Kapton: Miracle Material with a Tragic History

On a balmy September evening in 1998, Swissair flight 111 was in big trouble. A fire in the cockpit ceiling had at first blinded the pilots with smoke, leaving them to rely on instruments to divert the plane, en route from New York to Geneva, to an emergency landing at Halifax Airport in the Canadian province of Nova Scotia. But the fire raging above and behind the pilots, intense enough to melt the aluminum of the flight deck, consumed wiring harness after wiring harness, cutting power to vital flight control systems. With no way to control the plane, the MD-11 hit the Atlantic ocean about six miles off the coast. All 229 souls were lost.

It would take months to recover and identify the victims. The 350-g crash broke the plane into two million pieces which would not reveal their secrets until much later. But eventually, the problem was traced to a cascade of failures caused by faulty wiring in the new in-flight entertainment system that spread into the cockpit and doomed the plane. A contributor to these failures was the type of insulation used on the plane’s wiring, blamed by some as the root cause of the issue: the space-age polymer Kapton.

No matter where we are, we’re surrounded by electrical wiring. Bundles of wires course with information and power, and the thing that protects us is the thin skin of insulation over the conductor. We trust these insulators, and in general our faith is rewarded. But like any other engineered system, failure is always an option. At the time, Kapton was still a relatively new wonder polymer, with an unfortunate Achilles’ heel that can turn the insulator into a conductor, and at least in the case of flight 111, set a fire that would bring a plane down out of the sky.

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The Engineering Case for Fusing Your LED Strips

Modern LED strips are magical things. The WS2812 has allowed the quick and easy creation of addressable RGB installations, revolutionizing the science of cool glowy things. However, this accessibility means that it’s easy to get in over your head and make some simple mistakes that could end catastrophically. [Thomas] is here to help, outlining a common mistake made when building with LED strips that is really rather dangerous.

The problem is the combination of hardware typically used to run these LED strings. They’re quite bright and draw significant amounts of power, each pixel drawing up to 60 mA at full-white. In a string of just 10 pixels, the strip is already drawing 600 mA. For this reason, it’s common for people to choose quite hefty power supplies that can readily deliver several amps to run these installations.

It’s here that the problem starts. Typically, wires used to hook up the LED strips are quite thin and the flex strips themselves have a significant resistance, too. This means it’s possible to short circuit an LED strip without actually tripping the overcurrent protection on something like an ATX power supply, which may be fused at well over 10 amps. With the resistance of the wires and strip acting as a current limiter, the strip can overheat to the point of catching fire while the power supply happily continues to pump in the juice. In a home workshop under careful supervision, this may be a manageable risk. In an unattended installation, things could be far worse.

Thankfully, the solution is simple. By installing an appropriately rated fuse for the number of LEDs in the circuit, the installation becomes safer, as the fuse will burn out under a short circuit condition even if the power supply is happy to supply the current. With the example of 10 LEDs drawing 600 mA, a 1 amp fuse would do just fine to protect the circuit in the event of an accidental short.

It’s a great explanation of a common yet dangerous problem, and [Thomas] backs it up by using a thermal camera to illustrate just how hot things can get in mere seconds. Armed with this knowledge, you can now safely play with LEDs instead of fire. But now that you’re feeling confident, why not check out these eyeball-searing 3 watt addressable LEDs?

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3D Print Yourself A Flame Thrower

For a large proportion of the world’s population, it’s now winter, which means there’s plenty of rain and snow to go around. With the surrounding environment generally cooler and wetter than usual, it’s a great time to experiment with dangerous flame based projects, like this wrist mounted flame thrower.

It’s a build that does things in both a simple and complicated way, all at once. Fuel is provided by a butane canister with a nozzle that needs to be pressed to release the gas.  A servo is used to push the canister into a 3D printed housing, releasing the gas into a pipe to guide the fuel towards the end of the user’s wrist. The fuel is then ignited by a heated coil of wire. The heated wire and the servo are both controlled by standard radio control gear typically seen on RC cars or buggies. Using the brushed speed controller to run the heated coil is particularly off-beat, but it does the job admirably.

Overall, it goes without saying that this build presents some serious risks of burns and other injuries. However, the fundamental premise is sound, and it does what it says on the tin with parts that could be readily found in the average junk box.

For another take on a wrist-mounted flame thrower, check out this version using a scavenged solenoid valve.

Mike Ossmann and Dominic Spill: IR, Pirates!

Mike Ossmann and Dominic Spill have been at the forefront of the recent wave of software-defined radio (SDR) hacking. Mike is the hardware guy, and his radio designs helped bring Bluetooth and ISM-band to the masses. Dominic is the software guy who makes sure that all this gear is actually usable. The HackRF SDR is still one of the best cheap choices if you need an SDR that can transmit and receive.

So what are these two doing on stage giving a talk about IR communication? Can you really turn traffic lights green by blinking lights? And can you spoof a TV remote with a cardboard cutout, a bicycle wheel, and a sparkler? What does IR have to do with pirates, and why are these two dressed up as buccaneers? Watch our video interview and find out, or watch the full talk for all of the juicy details.

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This Power Strip is a Fire Starter

A few weeks ago I needed a power strip in my home office. The outlet in question is located behind a filing cabinet so it would need a low profile plug. I jumped on Amazon to buy a surge suppressor strip. That’s when I noticed strips with rotating plugs. I’ve always had some apprehensions about plugs like that, though I could never quite put my finger on why. Looking at the reviews on this particular plug, I found some scary issues. Photos of melted plugs, melted outlets, and cries of “fire hazard”. So I did what any crazy hacker would do – bought two power strips. One with a fixed right angle plug to use in my office, and one with a rotating plug to tear down.

Failed plug – from Amazon reviews

Surge suppressors, power strips, outlet strips, they have many names. Underwriter’s Laboratories (UL) calls them “Relocatable power taps”. They all have several outlets, most have a circuit breaker of some sort inside, and some have circuits for surge suppression. These are some of the most common devices to find in the modern home. Many of our houses were designed and built before surround sound, cable boxes, computers, modems, cell phone chargers, tablet chargers, and all our other modern conveniences. There weren’t as many electrical loads, so the houses didn’t have many outlets. Power strips solve this problem.

After a couple of days, I had my strips in hand. I expected the plug to rotate once – maybe 270 degrees. That would indicate there were wires connecting the rotating head to rest of the plug. Not so – this plug would spin round and round all day long.

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