Coil Gun For Newbies: Learning Electromagnetic Propulsion

There’s something attractive about coil guns, especially big ones. It’s probably the danger; between the charge stored in banks of capacitors and the flying projectiles, big coil guns can be lethal to experiment with. But there is a lot to be learned from how coil guns work, especially if you build this 3D-printed entry-level coil gun.

For the coil gun newbie, [Great Scott] does a fantastic job of explaining the basics. Pulsing the coil at just the right time will suck a ferromagnetic projectile into the coil core and let momentum fling it out, and multiple coils used correclty improve performance.

His gun is a simple pistol design with two coils, optical sensors to tell when the projectile is centered in each coil, and an Arduino to coordinate everything. The results are not spectacular — he uses only a modest amount of current — but the gun still works. [Great Scott] points out how a capacitor bank could be used to increase the current, but for the sake of keeping it simple he leaves that as an exercise for the builder.

Many coil gun and rail gun builds have made it to our pages over the years, including his ridiculously powerful gun that uses a capacitor bank so large it needs its own car. We like this build for its simplicity, its approachability, and the excellent explanation of its function.

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Electromagnetic Field’s Badge Hanging In The Balance

Making conference badges is a tough job. Unless you’re sitting on a gold mine, you have to contact a whole bunch of sponsors for help, work the parts that you can get into a coherent design, and do it all on the quick for a large audience. The EMF team is this close to getting it done, but they need some sponsorship for the assembly. If you know anyone, help them out! If they can’t line something up in the next two weeks, they’ll have to pull the plug on the badge entirely.

Electromagnetic Field is a summer-camp hacker convention / festival that takes place in England and is now in its third iteration. As with other big cons, the badge is a good part of the fun.

The 2016 EMF badge looks to be amazing. It’s powered by an ST STM32L4 low-power micro, a color LCD screen, a TI CC3100 WiFi radio module onboard, and a ridiculous number of other features including a gyro and magnetometer, and a giant battery. It’s also a testbed for the brand-new MicroPython, which aims to bring everyone’s favorite scripting language to embedded processors. In fact, they’ve largely built the MicroPython WiFi drivers for the badge.

If they can’t get a sponsor, all is not lost because everything is open source. We’ll all reap the benefits of their hard work. But that’s not the point. The point is that hundreds of hackers will be standing around in a field outside of London without the most audacious badge that we’ve seen designed dangling from their necks.
If you know anyone who can help, get in touch?

Thanks [schneider] for the tip!

Captain America’s Mighty Shield With 7200N Of Powerful Electromagnets!

At Hackaday, sometimes we nerd out a bit too hard over comic book movies. With Captain America: Civil War in theaters, I knew I had to do a project dedicated to the movie — so I made a ridiculously over powered electromagnet bracer. The hope? To attract a Captain America replica shield from short distances.

electromagnet bracerI had the idea for this project a while ago after watching Avengers: Age of Ultron.

If you’re not familiar, it appears Captain America gets a suit upgrade (presumably from Stark himself) that features some pretty awesome embedded electromagnets allowing him to call his shield back to him from afar.

Now unfortunately, electromagnets aren’t that strong and I knew I wouldn’t be able to achieve quite the same effect as good ol’ CGI — but I’d be darned not to try!  Continue reading “Captain America’s Mighty Shield With 7200N Of Powerful Electromagnets!”

Kids And Hacking: Electromagnetic Eggs

One of my favorite things to do is visit with school kids who are interested in engineering or science. However, realistically, there is a limit to what you can do in a single class that might last 30 to 90 minutes. I recently had the chance to work with a former colleague, a schoolteacher, and The Teaching Channel to create an engineering unit for classroom use that lasts two weeks.

This new unit focuses on an egg drop. That’s not an original idea, but we did add an interesting twist: the project develops a “space capsule” to protect the egg, but also an electromagnetic drop system to test the capsules. The drop system allows for a consistent test with the egg capsule releasing cleanly from a fixed height. So in addition to the classic egg drop capsule, the kids have to build an electromagnet, a safe switching circuit, and a test structure. Better still, teams of kids can do different parts and integrate them into a final product, closely mimicking how real engineering projects work.

There are a few reasons for the complexity. First, given ten class sessions, you can do a lot more than you can in a single day. Second, I always think it is good if you can find exercises that will appeal to lots of different interests. In the past, I’ve used robots and 3D printers for that reason. Some students will be interested in the electronics, others in the mechanics, and still others will be interested in the programming. Some kids will engage in 3D modeling (robot simulation or 3D objects). The point is there is something for everyone.

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image of the face of einstein

The Spooky Nature Of Electromagnetic Radiation

Our story begins a little over one hundred years ago in Bern, Switzerland, where a young man employed as a patent clerk went off to work. He took the electric trolley in each day, and each day he would pass an unassuming clock tower. But today was different, it was special. For today he would pose to himself a question – a question whose answer would set forth a fascinating dilemma.

The hands of the clock appeared to move the same no matter if his trolley was stopped or was speeding away from the clock tower. He knew that the electromagnetic radiation which enabled him to see the clock traveled at a finite speed. He also knew that the speed of the light was incredibly great compared to the speed of his trolley. So great that there would not be any noticeable difference in how he saw the hands of the clock move, despite him being at rest or in motion. But what if his trolley was moving at the speed of the reflected light coming from the clock? How would the hands of the clock appear to move? Indeed, they could not. Or if they did, it would not appear so to him. It would appear as if all movement of the clock’s hands had stopped – frozen in an instant of time.  But yet if he looked at the hands of the watch in his pocket, they would appear to move normally. How does one explain the difference between the time of the clock tower versus the time of his watch? And which one was correct?

There was no way for him to know that it would take three years to answer this question. No way for him to know that the answer would eventually lead to the discovery of matter and energy being one and the same. No way to know that he, this underemployed patent clerk making a simple observation, would soon unearth the answer to one of the greatest mysteries that had stumped every mind that came before his – the very nature of time itself.

Now it might have taken Einstein a few years to develop the answer we now know as the Special Theory of Relativity, but it most certainly took him no longer than a few days to realize that Isaac Newton…

must be wrong.

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Electromagnetic Boots For All Your Upside Down Needs!

magnet boots

X-Men: Days of Future Past is making its way to theaters around the world, and [Mr. Furze] has released his second X-Men related hack — Magneto Boots.

In case you missed it, [Colin Furze] has made three projects to celebrate geekdom and a mastery of fabrication for all the comic book fans out there. He started with the fully functional pneumatic Wolverine Claws, and now he’s tackling Magneto’s powers. The third project isn’t out quite yet, but we can’t wait to see the final installment!

Now the problem with Magneto is his powers are a wee bit too… magical? Without special effects, you can’t really replicate his mutant abilities (please prove us wrong if you can!), so [Colin] decided to do the next best thing. Magnetize himself — well, his shoes.

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Electromagnetic Spiderman Webshooter Railgun / Grappling Hook

spiderman grapple hook rail gun

As technology continues to advance, make-believe props and technology from movies are coming closer and closer to reality. [Patrick Priebe] has managed to put together a working Spiderman Webshooter with the help of electromagnets!

He’s built a tiny coil gun that puts out 100 Joules of energy using a 350V capacitor bank, which straps cleanly to his wrist over top of a Spiderman costume glove. It makes the classic high-pitched hum as it charges, and launches a small barbed brass arrow capable of skewering Styrofoam.

He didn’t stop there though! He’s created a handy little winch using a small high-powered brushless motor with an ESC. A weighted disk acts as a flywheel to increase the pulling power of the fishing line, and he’s built it on a pivot so when you launch it, the fishing line just slips off the end without resistance. To engage, you flip it back perpendicular to the line and turn on the motor.

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