Wield The Power Of Molten Metal

August 16, 2017 by James Hobson 16 Comments

[TheBackyardScientist] at it again with another super villain-esque demonstration of gadgetry: a liquid metal squirt gun.

The squirt gun has a compressed air tank like most others — more on that later — but to fire its primary ammunition, a nozzle that connects directly to an air compressor is needed. Again, like most guns of this nature, air is forced into the gun’s reservoir, displacing the pewter and expelling it out the gun’s barrel. Yes, pewter.

Working around the heat tolerances of thread seal tape, pewter has a low enough melting point that an airtight system is preserved — plus it’s really cool to fire a stream of liquid metal. The ammunition is made from pewter ware melted down and cast into pucks. These pucks are stacked into the gun’s magazine, melted with a propane torch and carefully loaded into the gun.

The built-in compressed air tank lacks the oomph to push out the pewter — hence the air compressor, but any lighter liquids or condiments are fair game for rapid-fire exercises. Yes, condiments.

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Fridge Compressor To 2-Stroke Engine: JB Weld For The Win

August 16, 2017 by Dan Maloney 28 Comments

We like this one because it has a real Junkyard Wars feel to it: turning a cast-off fridge compressor into a two-stroke internal combustion engine. [Makerj101] is doing this with tooling no more complicated than a hacksaw and a hand drill. And JB Weld — lots and lots of JB Weld.

[Makerj101]’s video series takes us through his entire conversion process. Despite the outward similarity between compressors and engines, there are enough crucial differences to make the conversion challenging. A scheme for controlling intake and exhaust had to be implemented, the crankcase needed to be sealed, and a cylinder head with a spark plug needed to be fabricated. All of these steps would have been trivial in a machine shop with mill and lathe, but [Makerj101] chose the hard way. An old CPU heat sink serves as a cylinder head, copper wire forms a head gasket and spacer to decrease the compression ratio, and the old motor rotor serves as a flywheel. JB Weld is slathered everywhere, and to good effect as the test run in the video below shows.

Think you recognize [Makerj101]? You probably do, since we featured his previous machine shop-less engine build. This guy sure gets his money’s worth out of a tube of JB Weld.

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Making A Coil Gun Without Giant Caps

August 16, 2017 by John Baichtal 26 Comments

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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Alexa In A Bunny Rabbit

August 16, 2017 by Inderpreet Singh 13 Comments

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” →

A Gas Model Made Of Magnets

August 15, 2017 by Manuel Rodriguez-Achach 16 Comments

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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Pouring 1200° Tea: Foundry In A Fire Extinguisher

August 15, 2017 by Dan Maloney 29 Comments

Let’s face it — the design of most home foundries leaves something to be desired. Most foundries are great at melting metal, but when it comes to pouring the melt, awkward handling can easily lead to horrific results. That’s why we appreciate the thought that went into this electric melting pot foundry.

Sure, electric foundries lack some of the sex-appeal of gas- or even charcoal-fueled foundries, but by eschewing the open flames and shooting sparks, [Turbo Conquering Mega Eagle] was able to integrate the crucible into the foundry body and create what looks for all the world like a Thermos bottle for molten aluminum.

The body is a decapitated fire extinguisher, while the crucible appears to just be a length of steel pipe. An electric stove heating element is wrapped around the crucible, PID control of which is taken care of by an external controller and solid state relay. Insulated with Pearlite and provided with a handle, pours are now as safe as making a nice cup of 1200° tea.

You’ll perhaps recall that [Turbo Conquering Mega Eagle] has a thing for electric foundries, although we have to say the fit and finish of the current work far exceeds his previous quick-and-dirty build using an old electric stove.

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Manually-Adjustable Three-Axis Gimbal

August 12, 2017 by John Baichtal 3 Comments

[Tim Good] built a 3-axis gimbal out of 3D-printed and machined pieces, and the resulting design is pretty sweet, with a nice black-on-black look. He machined the flat pieces because they were too long to be printed in his 3D-printer.

The various axes swivel on four bearings each, and each ring features a manual locking mechanism made out of steel stainless pins that immobilize each axis. The gimbal operation itself appears to be manual. That said, [Tim] used 12-wire slip rings to power whatever camera gets mounted on it–it looks like the central enclosure could hold a camera the size of a GoPro.

[Tim] has shared his design files on Thingiverse: it’s a complicated build with 23 different files. This complexity got us wondering: aren’t there two pitch axes?

We definitely love seeing gimbal projects here on Hackaday. A few cases in point, a gimbal-mounted quadcopter, another project with a LIDAR added to a camera gimbal, and this gimbal-mounted coffee cup.