Stun Gun vs 220v Mains Electricity

Those fearless Ukrainians are at it again! This time around they’re giving wall outlets some high voltage stun gun shocks and observing the results, as [Kreosan] decided to see what would happen when you use a stun gun on mains electrical sockets. Surprisingly, they are still alive and well, and creating more videos. .

Shocking a light switch blew up some light bulbs, while shocking an extension cord with a TV plugged in blew the TV up. It seems these guys never run out of appliances to fry, or totally insane experiments to try out that no one else would really have the stomach for.

Although their experiments are on the extreme side of things they do know what they are doing, as they are electrical professionals, So maybe sit this one out unless you too really know what you are doing and understand the risks. The video is below the break for your enjoyment.

We have featured some of their equally scary hacks in the past, like mains voltage EL wire and wirelessly charging your phone from high voltage overhead power lines.

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Embiggen your Eclipse 2017 Experience with a Sun Funnel

As exciting as Eclipse 2017 is going to be this Monday, for some folks it might appear a bit — underwhelming. Our star only occupies about half a degree of the sky, and looking at the partial phase with eclipse glasses might leave you yearning for a bigger image. If that’s you, you’ll need to build a sun funnel for super-sized eclipse fun.

[Grady] at Practical Engineering is not going to be lucky enough to be within the path of totality, but he is going to be watching the eclipse with a bunch of school kids. Rather than just outfitting his telescope with a filter and having the kids queue up for a quick peek, he built what amounts to a projection screen for the telescope’s eyepiece. It’s just a long funnel, and while [Grady] chose aluminum and rivets, almost any light, stiff material will do. He provides a formula for figuring out how long the funnel needs to be for your scope, along with plans for laying out the funnel. We have to take exception with his choice of screen material — it seems like the texture of the translucent shower curtain might interfere with the image a bit. But still, the results look pretty good in the video below.

Eclipse 2017 is almost here! How are you planning to enjoy this celestial alignment? By proving Einstein right? By studying radio propagation changes? Or just by wearing a box on your head? Sound off in the comments.

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Make A Badge When There Is No Badge Yet

What do you do when your keenly anticipated hacker camp releases details of its upcoming badge and you really want to have a go at coding for it, but there are no badges for you to try yet? If you are [Artdanion], this is not a problem, you simply build your own.

He found his requirement to interface with genuine hardware exceeded the abilities of the emulator that the SHACamp 2017 badge team had thoughtfully provided, so he reached for breakout boards for the ESP32, the MPR121 touch sensor, and the e-ink display, and assembled his own clone on a piece of stripboard. Not only did it provide him with enough to develop his own apps, he found when he brought it to the event that the public release of the official firmware ran on it with only a few configuration tweaks. He had an official event badge, that wasn’t the event badge. Is this the first time this has been done? We think it might be.

The home-made badge is an impressive piece of work, but it ties into an observation we made at the end of our review of the official version of the SHA2017 badge. The use of an ESP32 with well-designed peripherals and a solid firmware means that this is a design that is likely to form the bedrock upon which some future badges are built. [Artdanion] has proved how straightforward it is to clone, we’d like to be so bold as to make the prediction that we’ll see more developments of this platform at future events. Meanwhile this home-made badge is a neat achievement, and we can only imagine the surprise of the SHA2017 badge team on being presented with a clone of their work for reflashing.

Hackaday Prize Entry: Engine Control Units and Arduinos

The modern internal combustion engine is an engineering marvel. We’re light-years ahead of simple big blocks and carburetors, and now there are very fast, very capable computers sensing adjusting the spark timing, monitoring the throttle position, and providing a specific amount of power to the wheels at any one time. For the last few years [Josh] has been building a fully-featured engine management system, and now he’s entered it in the Hackaday Prize.

The Speeduino project is, as the name would suggest, built around the Arduino platform. In this case, an Arduino Mega. The number of pins and PWMs is important — the Speeduino is capable of running the fuel and ignition for eight cylinder engines.

The Speeduino is designed to do everything an engine control unit can do, including rev limiting (although if you’re building your own ECU, why?), and reading ethanol sensors. Right now [Josh] is working on a beta run of the Speeduino designed for the 1.6L Miata. That’s an excellent platform for firmware performance tuning, and there’s still a lot of work to be done on the firmware side of things before everything’s all set to go. Still, this is a great project and sure to impress the bros at track day, bro.

Reamer Regrinding Using a Toolpost Spindle

How often have you wished you could reduce the size of a drillbit? [Ben Katz] has a bunch of projects in mind that use a tight-tolerance 22mm bore–but he didn’t have a 22mm reamer handy. Rather than buy one, he thought, why not regrind a larger one to the right size?

He first ground down the shank to fit in the lathe’s drill chuck. Once it was loaded into the chuck,  he reground the edge of a 7/8″ (22.225mm) reamer, reducing its diameter down to 22mm by spinning it on his lathe in conjunction with a toolpost spindle with a grinding wheel attached. The final diameter was 21.995mm—off by 5 microns!

[Ben]’s homebuilt spindle is a cool project in itself, and we publish a lot of posts about those handy tools. Check out our pieces on a brushless DC motor used as a CNC spindle, and this 3D printer outfitted with a spindle. Also check out [Ben]’s electric tricycle build we featured a few years ago.

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Logic Gates Under (Air) Pressure

We’ve always been fascinated at the number of ways logic gates can spring into being. Sure, we think of logic gates carrying electrons, but there are so many other mechanical means to do the same thing. Another method that sometimes has a practical use is fluidic or pneumatic logic. We guess [dAcid] has a similar interest since he’s written two posts on how to construct the gates. One post covers making them with ordinary tools. The other requires an SLA printer.

According to [dAcid], the design is effectively the same either way, but the SLA printing is more precise. Silicone is an important component, either way. Fluidic logic has applications in some mechanical systems, although digital logic has made it less important than it once was. However, it is very possible that nanotechnology systems will implement logic mechanically, so this is still an interesting technique to understand. You can see videos of how a D latch looks using both methods, below.

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Project Kino: Robotic Jewelry And Tech Accessory

Researchers from MIT and Stanford are taking the ‘person’ in ‘personal assistant’ to mean something more literal with these robots that scurry around on the user’s clothing.

Project Kino — inspired by living jewelry — are robotic accessories that use magnetic gripping wheels on both sides of the clothing to move about. For now they fill a mostly aesthetic function, creating kinetic accents to one’s attire, but one day they might be able to provide more interactive functionality. They could act as a phone’s mic, adjust clothing to suit the weather, function as high-visibility wear for cyclists or joggers, as haptic feedback sensors for all manner of applications (haptic sonar bodysuit, anyone?), assemble into large displays, and even function as a third — or more! — hand are just the tip of the iceberg for these ‘bots.

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