With All Hallow’s Eve looming close, makers have the potential to create some amazing costumes we’ll remember for the rest of the year. If you’re a fan of the hugely addict-*cough* popular game Minecraft, perhaps you’ve considered cosplaying as your favorite character skin, but lacked the appropriate props. [Graham Kitteridge] and his friends have decided to pay homage to the game by making their own light-up Minecraft swords.
These swords use 3D-printed and laser-cut parts, designed so as to hide the electronics for the lights and range finder in the hilt. Range finder? Oh, yes, the sword uses an Arduino Uno-based board to support NewPixels LEDs and a 433Mhz radio transmitter and receiver for ranged detection of other nearby swords that — when they are detected — will trigger the sword to glow. Kind of like the sword Sting, but for friendlies. Continue reading “Minecraft Sword Lights Up When Nearby Friends”
[Guy in a garage] has made a 3D printed gun that not only appears to fire in the direction pointed, it can also do it multiple times. Which, by the standard of 3D printed guns, is an astounding feat. He started with .22 rifle cartridges but has since upgraded and tested the gun with .357 rounds. The link above is a playlist which starts of with an in-depth explanation of the .22 version and moves through design iterations
This gun prints on a standard FDM printer. Other 3D printable guns such as the infamous Liberator or the 3D printed metal gun need more exotic or precise 3D printing to work effectively. The secret to this gun’s ability is the barrel, which can be printed in nylon for .22 cartridges, or in ABS plus a barrel liner for .22 and .357 caliber.
A barrel liner is one way to repair a gun that has aged and is no longer shooting properly. Simply put, it is a long hardened metal tube with rifling on the inside. Some guns come out of the factory with one, and a gunsmith simply has to remove the old one and replace it. Other guns need to be bored out before a liner can be installed.
The metal liner surrounded by plastic offers enough mechanical strength for repeat firings without anyone losing a hand or an eye; though we’re not sure if we recommend firing any 3D printed gun as it’s still risky business. It’s basically like old stories of wrapping a cracked cannon in twine. The metal tries to expand out under the force of firing, but the twine, which would seem like a terrible material for cannon making, is good in tension and when wrapped tightly offers more than enough strength to hold it all together.
This is also how he got the .357 version to work. The barrel slots into the gun frame and locates itself with a rounded end. However, with the higher energy from a .357 round, this rounded end would act as a wedge and split the 3D printed frame. The fix for this was simple. Glue it back together with ABS glue, and then wrap the end of the assembly with a cable tie.
This is the first 3D printed gun we’ve seen that doesn’t look like a fantastic way to instantly lose your hand. It’s a clever trick that took some knowledge of guns and gunsmithing to put together. Despite the inevitable ethical, moral, and political debate that will ensue as this sort of thing becomes more prevalent, it is a pretty solid hack and a sign that 3D printing is starting to work with more formidable engineering challenges.
Coilguns used to be the weapons of science fiction. Nowadays, whenever we see someone build one in their workspace it always serves as an inspiring reminder that the future is now. YouTuber [Cody’sLab] has done just that, assembling a rudimentary — but beefy — coilgun in his workshop.
The one in the video is based off an old design that used a 12V battery and without any fancy electronics. This new model has five coil stages along its two-foot length. Four wooden dowels and two copper tubes are arranged in a hexagonal shape to form the barrel and accelerator rails. The coils are each 100 feet of 14-gauge thin coated copper wire, all connected to a common ground. Still lacking any complex electronics, this version eventually gets its projectile launched a good few dozen feet. The ‘bullet’ is a piece of steel with some brass to prevent it spinning in the barrel, while a hole has been drilled in it to accommodate a spring which keeps the two graphite brushes contacting the copper tubes.
The first test proved to be a little underwhelming, and [Cody] had to try something drastic — so he hooked it up to an arc welder to fire the projectile using 22V and 200A.
Continue reading “Five-Stage Coilgun Powered by an Arc Welder!”
Looks like another shot has been fired in the simmering Coil Gun Control War. This time, [Great Scott] is taken to the discrete woodshed with a simplified and improved control circuit using a single CMOS chip and a few transistors. Where will it end? Won’t somebody think of the children?
The latest salvo is in response to [GreatScott]’s attempt to control a DIY coil gun with discrete logic, which in turn was a response to comments that he took the easy way out and used an Arduino in the original build. [Great Scott]’s second build was intended to justify the original design choice, and seemed to do a good job of explaining how much easier and better the build was with a microcontroller. Case closed, right?
Nope. Embedded designer [fede.tft] wasn’t sure the design was even close to optimized, so he got to work — on his vacation, no less!’ He trimmed the component count down to a single CMOS chip (a quad Schmitt trigger NAND), a couple of switching transistors, the MOSFETs that drive the coils, and a few passives. The NANDs are set up as flip-flops that are triggered and reset by the projectile sensors, which are implemented as hardwired AND gates. The total component count is actually less than the support components on the original Arduino build, and [fede.tft] goes so far as to offer ideas for an alternative that does away with the switching transistors.
Even though [fede.tft] admits that [GreatScott] has him beat since he actually built both his circuits, hats off to him for showing us what can likely be accomplished with just a few components. We’d like to see someone implement this design, and see just how simple it can get.
A common complaint in the comments of many a Hackaday project is: Why did they use a microcontroller? It’s easy to Monday morning quarterback someone else’s design, but it’s rare to see the OP come back and actually prove that a microcontroller was the best choice. So when [GreatScott] rebuilt his recent DIY coil gun with discrete logic, we just had to get the word out.
You’ll recall from the original build that [GreatScott] was not attempting to build a brick-wall blasting electromagnetic rifle. His build was more about exploring the concepts and working up a viable control mechanism for a small coil gun, and as such he chose an Arduino to rapidly prototype his control circuit. But when taken to task for that design choice, he rose to the challenge and designed a controller using discrete NAND and NOR gates, some RS latches, and a couple of comparators. The basic control circuit was simple, but too simple for safety — a projectile stuck in the barrel could leave a coil energized indefinitely, leading to damage. What took a line of code in the Arduino sketch to fix required an additional comparator stage and an RC network to build a timer to deenergize the coil automatically. In the end the breadboarded circuit did the job, but implementing it would have required twice the space of the Arduino while offering none of the flexibility.
Not every project deserves an Arduino, and sometimes it’s pretty clear the builder either took the easy way out or was using the only trick in his or her book. Hats off to [GreatScott] for not only having the guts to justify his design, but also proving that he has the discrete logic chops to pull it off.
Continue reading “DIY Coil Gun Redux: Life Really is Easier with Arduino”
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.
Continue reading “Coil Gun for Newbies: Learning Electromagnetic Propulsion”
At frustratingly regular intervals, the debate around gun control crops up, and every time there is a discussion about smart guns. The general idea is to have a gun that will not fire unless authenticated and authorized. There’s usually a story about a young person who invents a smart controller and another company that is struggling because they just can’t get “Big Guns” to buy into the idea. We aren’t going to focus on the politics; we’re going to look at whether the technology is realistic, and why a lot of the news stories about new tech never pan out.
Let’s start with an example of modern technology creeping into established machines: the car. These are giant hunks of metal with nearly constant explosions, controlled by sophisticated electronics that are getting smarter and more connected every day. Industry is adopting it with alacrity, and the vehicles are getting more efficient and powerful because of it. So why can’t firearms?
Continue reading “Firearm Tech – Are Smart Guns Even Realistic?”