Making A Coil Gun Without Giant Caps

Whenever we see a coil gun project on the Internet, it seems to involve a bank of huge capacitors. [miroslavus] took a different approach with his gun–he wanted his project to be built without those monster caps.

It’s powered by quadcopter LiPo batteries, 2x 1400 MaH drone batteries wired up in series and triggering 21SWG copper coils that [miroslavus] created with the help of a custom 3D-printed winding rig he designed. The rigs have ridges to help you lay the coils down neatly, and they also have mounts for photodiodes, ensuring the gun knows when it’s loaded.

When triggered, the Arduino Nano activates a pair of IRF3205 MOSFETS with logic signals stepped up to 20V, shooting lengths of 7mm or 8mm steel rod. The gun isn’t exactly creating plasma discharges with its launches, but it’s a fascinating project nonetheless.

Check out the disposable camera coil gun project and the coil guns for newbies posts we previously ran.

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Eclipse 2017: Was Einstein Right?

While most people who make the trek to the path of totality for the Great American Eclipse next week will fix their gazes skyward as the heavenly spectacle unfolds, we suspect many will attempt to post a duck-face selfie with the eclipsed sun in the background. But at least one man will be feverishly tending to an experiment.

On a lonely hilltop in Wyoming, Dr. Don Bruns will be attempting to replicate a famous experiment. If he succeeds, not only will he have pulled off something that’s only been done twice before, he’ll provide yet more evidence that Einstein was right.

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Alexa In A Bunny Rabbit

The Raspberry Pi is the perfect candidate for Google’s AIY where you can talk to a cardboard box with some electronics in it. [BuddyCasino] took on the challenge of squeezing an Alexa Client in an ESP32 and to make things interesting, a bunny rabbit was chosen as the host of the virtual assistant.

A few months ago, we did a teardown of the Google AIY Kit where [BuddyCasino] commented that he managed to port the Echo Dot client into and ESP32. Sure enough, the video below shows a demonstration of the build in action. The project uses the MAX98357A which is the same I2S DAC used in the Google AIY Voice Hat. For the microphone, the device is again an I2S component however unlike the Google AIY kit which uses the SPH0645LM4H, [BuddyCasino] opted for the ICS-43434.

Two NeoPixels are employed as visual indicators for various purposes. This project is an excellent example of how simple and cheap modern-day designs have become. We are hoping to see the author add more features to the design and who knows maybe we will see a Google Assistant port on the ESP32 in the future. Check out the original teardown for more inspiration. Continue reading “Alexa In A Bunny Rabbit”

You Probably Don’t Want To Find This Toilet In Your Washroom

Ok, this one is a bit bizarre, but in perfect keeping with the subject matter: a talking toilet ripped from the pages of the Captain Underpants children’s books. Hackaday.io user [hamblin.joe]’s county fair has a toilet decorating contest and at the suggestion of their neighbour’s son, [hamblin.joe] hatched a plan to automate the toilet using an Arduino in the fashion of the hero’s foes.

Two Arduinos make up this toilet’s brains, an Adafruit Wave Shield imbues it with sound capabilities, and a sonic wave sensor will trigger the toilet’s performance routine when someone approaches. A windshield wiper motor actuates the toilet bowl lid via a piece of flat iron bar connected to a punched angle bracket. Installing the motor’s mount was a little tricky, since it had to be precisely cut so it wouldn’t shift while in the toilet bowl. A similar setup opens the toilet tank’s lid, but to get it working properly was slightly more involved. Once that was taken care of there was enough room left over for a pair of 12V batteries and a speaker. Oh, and a pair of spooky eyes and some vicious looking teeth.

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GuitarBot Brings Together Art And Engineering

Not only does the GuitarBot project show off some great design, but the care given to the documentation and directions is wonderful to see. The GuitarBot is an initiative by three University of Delaware professors, [Dustyn Roberts], [Troy Richards], and [Ashley Pigford] to introduce their students to ‘Artgineering’, a beautiful portmanteau of ‘art’ and ‘engineering’.

The GuitarBot It is designed and documented in a way that the three major elements are compartmentalized: the strummer, the brains, and the chord mechanism are all independent modules wrapped up in a single device. Anyone is, of course, free to build the whole thing, but a lot of work has been done to ease the collaboration of smaller, team-based groups that can work on and bring together individual elements.

Some aspects of the GuitarBot are still works in progress, such as the solenoid-activated chord assembly. But everything else is ready to go with Bills of Materials and build directions. An early video of a strumming test proof of concept used on a ukelele is embedded below.

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The Latest Hacker Camp Badge Comes From BornHack

If you’re a fan of outdoor hacker camps, or if you’re a SHACamp attendee who’s still coming down from the event high, you may already know about the upcoming BornHack 2017 hacker camp on the Danish island of Bornholm, from the 22nd to the 29th of this month. It’s a smaller camp than many of the others on the calendar, but it makes up for that with a quite reasonable ticket price, a much longer duration, and a location that is a destination in itself.

Today we have news of the BornHack badge announcement, and though the details are a little sketchy it’s safe to say that there should be plenty there to keep attendees occupied. The irregularly-shaped PCB contains a Silicon Labs “Happy Gecko” EFM32 ARM Cortex M0 microcontroller, a 128×64 pixel OLED display, and the usual array of I/O lines. There is no information about its connectivity as it seems the BornHack folks prefer to run a teaser campaign, but we’d be surprised if there wasn’t some kind of wireless module on the reverse.

Barring a transportation miracle it’s unlikely that any of the Hackaday team will be making it to BornHack, but that’s our loss. It may not be one of the larger camps, but it looks to offer no less of the atmosphere you’d expect from a European hacker camp. At the time of writing there are still BornHack tickets to be had, so head on over to their website if you fancy a week at a hacker camp on a Danish island.

A Gas Model Made Of Magnets

Magnets are great stuff and everyone loves them, there are so many things you can do with them, including creating a model of the crystalline structure of solids, just as [Cody´s Lab] did using a bunch of magnets inside a pair of plexiglass sheets.

Crystal structure of ice. Image from Wikemedia Commons.

Many materials have their atoms arranged in a highly ordered microscopic structure — a crystal — including most metals, rocks, ceramics and ice, among others. The structure emerges when the material solidifies looking for the minimum energy configuration. Every atom interacts with its neighbors via microscopic forces forming several patterns depending on the specific material and conditions.

In his macroscopic world, [Cody´s Lab] used the magnets as his “atoms” and the magnetic repulsion between them represent the microscopic forces. Confining the magnets inside two transparent walls, one can see the formation of the crystal structure as magnets are added one by one.

This is an excellent teaching resource and also a fun way to play with magnets if you want to give it a try. Or if you want another magnet hack, we have tons of them, including implanting them in your body, or making your own with 3D printing.

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