It doesn’t take long after getting a cat in your life to learn who’s really in charge. Cats do pretty much what they want to do, when they want to do it, and for exactly as long as it suits them. Any correlation with your wants and needs is strictly coincidental, and subject to change without notice, because cats.
[Alvaro Ferrán Cifuentes] almost learned this the hard way, when his cat developed a habit of exploring the countertops in his kitchen and nearly turned on the cooktop while he was away. To modulate this behavior, [Alvaro] built this AI Nerf turret gun. The business end of the system is just a gun mounted on a pan-tilt base made from 3D-printed parts and a pair of hobby servos. A webcam rides atop the gun and feeds into a PC running software that implements the YOLO3 localization algorithm. The program finds the cat, tracks its centroid, and swivels the gun to match it. If the cat stays in the no-go zone above the countertop for three seconds, he gets a dart in his general direction. [Alvaro] found that the noise of the gun tracking him was enough to send the cat scampering, proving that cats are capable of learning as long as it suits them.
[Eric] does, and like everything else about reloading, trickling is serious business. Getting an exact charge of powder to add to a cartridge is not a simple task, and very tedious when done manually. This smartphone-controlled auto-trickler is intended to make the job easier, safer, and more precise.
Reloading ammunition is a great way for shooters to save money and recycle the brass casings that pile up at the end of a long day at the range. It can be a fairly simple process of cleaning the casings, replacing the spent primers, adding the correct powder charge, and seating a new bullet. It’s all pretty straightforward, but the devil is in the details, especially with the powder charge. A little too much can be a big problem, so tricklers were invented to allow the reloader to sneak up on the proper charge. [Eric]’s auto-trickler interfaces to a digital powder scale and uses a standard cell phone vibration motor to gently coax single kernels of powder from a hopper until the proper charge has accumulated. It’s easier to understand by watching the video below.
The hardware behind the trickler is pretty standard — just a Raspberry Pi Zero to talk to the smartphone UI via Bluetooth, and to monitor and control the scale via USB. [Eric] has made all the code open source so that anyone can build their own auto-trickler, which we applaud; he did the same thing with his rifle-mounted accelerometer. This project might have applications far beyond reloading where precision dispensing is required.
It’s not particularly easy to buy small explosive charges. At least, it’s not in the UK, from where [Turbo Conquering Mega Eagle] hails. But it is surprisingly easy to get your hands on one because most people drive around with one right in front of them in the form of their car airbag. In a burst of either genius or madness, we can’t decide which, he decided to use an airbag charge to launch a projectile.
As you can see in the video below, he launches straight into dismantling the centre of a Renault steering wheel before seemingly abandoning caution and taking a grinder to the charge inside. It’s a fascinating deconstruction though, because it reveals not one but two differently sized charges separated by a space which appears to contain some kind of wadding.
His projectile is a piece of steel tube with a turned steel point, spigot launched over a tube placed in front of a breech in which he places the charge. The launch tube has a piece of metal welded within it, he tells us to render it legal by being unable to launch a projectile from within it. Upon firing at a scrap jerry can it has enough energy to easily pass through both its steel walls, so it’s quite a formidable weapon.
He assures the viewer that with the spigot-launched design he’s not breaking the law, but we’re not sure we’d like to have to explain that one to a British policeman. He does make the point though that while it’s an impressive spectacle it’s also quite a dangerous device, so maybe don’t do this at home.
The cannon has a rotary barrel driven by a small motor, and a clever sear design uses the rotation of the barrels like a worm gear. The rotating barrel has a spiral formation of hooks which anchor the stretched elastic bands. A small ramp rides that spiral gap, lifting ends of stretched bands one at a time as the assembly turns. This movement (and therefore the firing control) is done with a small continuous rotation servo. While in theory any motor would do, using a servo has the advantage of being a standardized shape, and therefore easy to integrate into the design. A video is embedded below in which you can see it work, along with some close-ups of the action.
[CutTransformGlue] recently posted a build video for “Making Rey’s Star Wars Blaster“, embedded after the break. The construction uses layered MDF sheets to build up the blaster, and it’s a treat to see it taking shape, ending with an amazing paint job. It’s a good way to learn about the techniques used to bring such props to life and help you hone your skills. But digging deeper led us down an awesome rabbit hole.
[CutTransformGlue] got plans for Rey’s Blaster from the Punished Props Academy – a prop and costume making team from Seattle committed to “transforming passionate fans into confident, skillful makers”. These folks have built a wide variety of projects ranging from guns, weapons, costumes, props and more, and are obviously extremely skilled at what they do. But they aren’t keeping those skills to themselves and in a series of posts and videos they are sharing with us such varied skills as Foamsmithing (gotta love that coinage), Molding, Casting, Painting, 3D printing, Vacuum Forming and electronics. If you’d like more information about supplies, check out the Tools and Materials section. And if all of this has given you the itch to build a Skyrim Wuuthrad or a Halo4 Sniper Rifle, head over to the amazing Free Blueprints section for a treasure chest full of downloads.
Like we said earlier, if building such stuff is your thing, it’s a rabbit hole from which you’ll find it extremely difficult to extract yourself. Have fun.
People unfamiliar with shooting sports sometimes fail to realize the physicality of getting a bullet to go where you want it to. In the brief but finite amount of time that the bullet is accelerating down the barrel, the tiniest movement of the gun can produce enormous changes in its trajectory, and the farther away your target is, the bigger the potential error introduced by anticipating recoil or jerking the trigger.
Like many problems this one is much easier to fix with what you can quantify, which is where this DIY rifle accelerometer can come in handy. There are commercial units designed to do the same thing that [Eric Higgins]’ device does but most are priced pretty dearly, so with 3-axis accelerometer boards going for $3, rolling his own was a good investment. Version 1, using an Arduino Uno and an accelerometer board for data capture with a Raspberry Pi for analysis, proved too unwieldy to be practical. The next version had a much-reduced footprint, with a Feather and the sensor mounted in a 3D-printed tray for mounting solidly on the rifle. The sensor captures data at about 140 Hz, which is enough to visualize any unintended movements imparted on the rifle while taking a shot. [Eric] was able to use the data to find at least one instance where he appeared to flinch.
With a highly publicized test firing and pledge by President Vladimir Putin that it will soon be deployed to frontline units, Russia’s Avangard hypersonic weapon has officially gone from a secretive development program to an inevitability. The first weapon of its type to enter into active service, it’s capable of delivering a payload to any spot on the planet at speeds up to Mach 27 while remaining effectively unstoppable by conventional missile defense systems because of its incredible speed and enhanced maneuverability compared to traditional intercontinental ballistic missiles (ICBMs).
In a statement made after the successful test of Avangard, which saw it hit a target approximately 6,000 kilometers (3,700 miles) from the launch site, President Putin made it clear that the evasive nature of the weapon was not to be underestimated: “The Avangard is invulnerable to intercept by any existing and prospective missile defense means of the potential adversary.” The former Soviet KGB agent turned head of state has never been one to shy away from boastful claims, but in this case it’s not just an exaggeration. While the United States and China have been working on their own hypersonic weapons which should be able to meet the capabilities of Avangard when they eventually come online, there’s still no clear deterrent for this type of weapon.
Earlier in the year, commander of U.S. Strategic Command General John Hyten testified to the Senate Armed Services Committee that the threat of retaliation was the best and perhaps only method of keeping the risk of hypersonic weapons in check: “We don’t have any defense that could deny the employment of such a weapon against us, so our response would be our deterrent force.” Essentially, the threat of hypersonic weapons may usher in a new era of “mutually assured destruction” (MAD), the Cold War era doctrine that kept either side from firing the first shot knowing they would sustain the same or greater damage from their adversary.
With President Putin claiming Avangard has already entered into serial production and will be deployed as soon as early 2019, the race is on for the United States and China to close the hypersonic gap. But exactly how far away is the rest of the world from developing an operational hypersonic weapon? Perhaps more to the point, what does “hypersonic weapon” really mean?