Six Shooter Swaps Powder For Popped Capacitors

August 29, 2022 by Tom Nardi 43 Comments

Modern firearms might seem far removed from the revolvers of the Old West, but conceptually, they still operate on the same principle: exploding gunpowder. But as anyone who has put too much voltage through an electrolytic capacitor knows, gunpowder isn’t the only thing that explodes. (Yes, it isn’t technically an explosion.)

[Jay Bowles] wondered if it would be possible to construct an electrically-fired weapon that used used a standard capacitor in place of the primer and powder of a traditional cartridge. While it would naturally have only the fraction of the muzzle velocity or energy of even the smallest caliber firearm, it would be an interesting look at an alternate approach to what has been considered a largely solved problem since the mid-1800s.

In his latest Plasma Channel video, [Jay] walks viewers through the creation of his unconventional pistol, starting with a scientific determination of how much energy you can get out of popped capacitor. His test setup involved placing a capacitor and small projectile into an acrylic tube, and noting the relation between the speed of the projectile and the voltage passed through the cap. At 30 VDC the projectile would reliably fire from the barrel of his makeshift cannon, but by tripling the voltage to 90 VDC, he noted that the muzzle velocity saw the same 3X improvement.

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Knife Throwing Machine Gets The Spin Just Right

August 23, 2022 by Danie Conradie 18 Comments

Despite how it might appear in bad action movies, throwing a knife and making it stick in a target is no easy feat. Taking inspiration from the aforementioned movies, [Quint] and his son built a magazine-fed knife throwing machine, capable of sticking a knife at any distance within its range.

Throwing a sharp piece of metal with a machine isn’t that hard, but timing the spin to hit the target point-first is a real challenge. To achieve this, [Quint] used a pair of high-performance servo motors to drive a pair of parallel timing belts. Mounting a carriage with a rotating knife-holder between the belts allows for a spinning throw by running one belt slightly faster. The carriage slides on a pair of copper rails, which also provide power to the knife holder via a couple of repurposed carbon motor brushes.

At first, the knife holder was an electromagnet, but it couldn’t reliably hold or release the stainless steel throwing knives. This was changed to a solenoid-driven mechanism that locks into slots machined into the knives. Knives are fed automatically from a spring-loaded magazine at the back as long as the trigger is held down, technically making it full-auto. To match the spin rate to the throwing distance, a LIDAR sensor is used to measure the distance, which also adjusts the angle of the aiming laser to compensate for the knife’s trajectory.

The development process was fraught with frustration, failure, and danger. Unreliable knife holders, exploding carriages, and faulty electronics that seemingly fired of their own accord were all challenges that needed to be overcome. However, the result is a machine that can both throw knives and nurture a kid’s passion for building and programming.

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A flat LiIon battery shown attached inside the gun safe, wired to the original control board

Gun Safe Made Safer With Lithium Battery Upgrade

April 18, 2022 by Arya Voronova 37 Comments

A proper gun safe should be difficult to open, but critically, allow instant access by the authorized party.[Dr. Gerg] got a SnapSafe and discovered that, while it was quite easy to use, it would also lock the owner out easily whenever the batteries would run out. Meant to be used with four AAA batteries and no way to recharge them externally, this could leave you royally screwed in the exact kind of situation where you need the gun safe to open. This, of course, meant that the AAA batteries had to go.

Having torn a few laptop batteries apart previously, [Dr. Gerg] had a small collection of Li-ion cells on hand – cylindrical and pouch cells alike. Swapping the AAA battery holder for one of these was no problem voltage-wise, and testing showed it working without a hitch! However, replacing one non-chargeable battery with another one wasn’t a viable way forward, so he also added charging using an Adafruit LiPo charger board. One 3D printed OpenSCAD-designed bracket later, he fit the board inside the safe’s frame – and then pulled out a USB cable for charging, turning the battery into a backup option and essentially creating an UPS for this safe. Nowadays, the safe sits constantly plugged into a wall socket, and [Dr. Gerg] estimates it should last for a few weeks even in case of USB power loss.

When you read about hacking gun safes, it’s usually because of their poor security, with even biometric models occasionally falling victim to prying fingers. There’s talk about moving the locking features into the guns themselves, but we remain skeptical. “Powering an electronically locked box with internal batteries” is a fun problem, and just recently, we’ve seen it solved in a different way in this intricate voice-activated lockbox.

Beautiful Engineering In This Laser Unit From A Tornado Jet Fighter

March 13, 2022 by Dave Rowntree 18 Comments

Those of use hailing from the UK may be quite familiar with the Royal Air Force’s Tornado fighter jet, which was designed to fight in a theoretical nuclear war, and served the country for over 40 years. This flying deathtrap (words of an actual serving RAF fighter pilot this scribe met a few years ago) was an extremely complex machine, with state-of-the-art tech for its era, but did apparently have a bit of a habit for bursting into flames occasionally when in the air!

Anyway, the last fleet is now long retired and some of the tech inside it is starting to filter down into the public domain, as some parts can be bought on eBay of all places. [Mike] of mikeselectricstuff has been digging around inside the Tornado’s laser head unit, which was part of the bomber’s laser-guided missile subsystem, and boy what a journey of mechanics and electronics this is!

This unit is largely dumb, with all the clever stuff happening deep in an avionics bay, but there is still plenty of older high-end tech on display. Using a xenon-discharge-tube pumped yttrium aluminum garnet (YAG) laser, operating in pulsed mode, the job of the unit is to illuminate the ground target with an IR spot, which the subsequently fired missiles will home on to.

Designed for ground-tracking, whilst the aircraft is operating at speed, the laser head has three degrees of moment, which likely is synchronized with the aircraft movement to keep the beam steady. The optical package is quite interesting, with the xenon tube and YAG rod swimming in a liquid cooling bath, inside a metal housing. The beam is bounced around inside the housing using many prisms, and gated with a Q-switch which allows the beam to build up in intensity, before be unleashed on the target. Also of note is the biggest photodiode we’ve ever seen — easily over an inch in diameter, split into four quadrants, enabling the sensor to resolve direction changes in the reflected IR spot and track its error. A separate photodiode receiver forms part of the time-of-flight optical range finder, which is also important information to have when targeting.

There are plenty of unusual 3-phase positioning motors, position sensors, and rate gyros in the mix, with the whole thing beautifully crafted and wired-up military spec. It is definitely an eye opener for what really was possible during the cold war years, even if such tech never quite filtered down to civilian applications.

We’ve seen a few bits about the Tornado before, like this over-engineered attitude indicator, and here’s the insides of an old aircraft QAR (Quick Access Recorder)

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The Fliegerfaust Roars Back To Life After 77 Years

March 9, 2022 by Tom Nardi 36 Comments

As their prospects for victory in the Second World War became increasingly grim, the Germans developed a wide array of outlandish “Wonder Weapons” that they hoped would help turn the tide of the war. While these Wunderwaffe obviously weren’t enough to secure victory against the Allies, many of them represented the absolute state-of-the-art in weapons development, and in several cases ended up being important technological milestones. Others faded away into obscurity, sometimes with little more then anecdotal evidence to prove they ever even existed.

One of these forgotten inventions is the Fliegerfaust, a portable multi-barrel rocket rocket launcher designed for use against low-flying attack planes. Although thousands were ordered to defend Berlin in 1945, fewer than 100 were ever produced, and there’s some debate about how many actually survived the war. But that didn’t stop [Jonathan Wild] of Wild Arms Research & Development from building a functional replica of the weapon based on contemporary documentation and blueprints.

Building the launcher was relatively straightforward, as it’s little more than nine tubes bundled together with a handle and a simplistic electric igniter. The trick is in the 20 mm (0.78 inch) rockets themselves, which are spin stabilized by the exhaust gasses exiting the four angled holes on the rear. With no fins or active guidance the path of each rocket is somewhat unpredictable, but this was known to be true of the original as well.

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Building A Lightsaber And Scoring A World Record, Too

January 25, 2022 by Lewin Day 32 Comments

As we all know, the lightsaber is an elegant weapon, for a more civilized age. [Alex Burkan] is doing what he can to bring that technology to fruition, and even secured a Guinness World Record in the process.

The build relies on an electrolyzer, splitting water into hydrogen and oxygen gas which is stored in a small tank. This gas can then be released and combusted in a burning stream, creating a weapon with a vague resemblance to a movie-spec lightsaber. With the hydrogen torch burning at temperatures of thousands of degrees, it’s hot enough to melt steel just like in the films.

While the concept of operation is simple, actually building such a device in a handheld size is incredibly difficult. [Alex] highlights key features such as the flashback arrestor that stops the gas tank exploding, and the output nozzle that was carefully designed to produce a surprisingly long and stable flame.

The resulting device only burns for 30 seconds, so you’ve only got a short period of time to do what you need to do. However, unlike previous designs we’ve seen, it doesn’t use any external gas bottles and is entirely self-contained, marking an important step forward in this technology. Video after the break.

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A row of electromagnetic coils fastened to a metal track

Propel Paper Planes, Bisect Sausages With Electromagnets

November 14, 2021 by Chris Wilkinson 7 Comments

Are you still launching paper airplanes using your hands? That’s like a baby’s toy! [Tom Stanton] and his homebrew electromagnetic rail launcher are sure to bring your paper airplane game into the 21st century.

To be fair, these kinds of linear motors can be used for more than just launching paper airplanes, and can already be found in niche industrial applications, mass transportation systems and roller coasters. And, yes, the potential to leverage electromagnetism in the theater of war is also being vigorously explored by many of the world’s superpowers in the form of Gauss rifles and railguns. In the meantime, the video (after the break) proves that it’s entirely possible to build a rudimentary yet effective linear motor in your makerspace, using relatively basic components and fundamental physics.

In short, these launch systems use electromagnetism and well timed electronics to propel a mass of magnetic material down a straight (or sometimes curved) track. Multiple pairs of coils are placed along the track, with each pair subsequently energized by high current as the payload approaches. By using many coils in succession, the mass and its payload can be accelerated to high speed.

While a homemade rail launcher is unlikely to turn the tides of war, [Tom Stanton] explores their lethal potential with an experiment involving high-speed video and supermarket sausages, with gruesome results.

If you’re looking for more, why not check out our our previous coverage on electromagnetic weaponry?

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