slingshot

15 Articles

Lego Tank Fires Soccer Ball Cannon

January 15, 2021 by 5 Comments

Back in the 20th century, Lego Technic was a popular toy designed to teach kids about mechanical technology, and be a lot of fun to boot. Motors and pneumatics were available, but by and large you had to move your creations and make the noises yourself. That’s not the case these days, as the [Brick Experiment Channel] demonstrates with this impressive Lego tank.

The drivetrain is straightforward, using standard Lego tank treads with each side given its own motor for easy skid steering. However, the real party piece is the slingshot cannon, which launches Lego soccer balls at 60 km/h. Utilizing several motors, it’s complete with elevation adjustment for accurate ranging, and a 6 round magazine so you can (slowly) prosecute your targets with rounds downrange.

What really makes this build great is the control system, with the tank being controlled by a PS4 controller via Sbrick, a device that lets Lego motors be controlled via Bluetooth. We’d love to build a couple of Lego vehicles and have them blast away at each other. We’ve seen the technology used before for a secret heist robot. Video after the break.

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Watch A Sand-Cast Slingshot Made, From Start To Finish

December 18, 2019 by 13 Comments

Sand-casting metal parts is a technique that has been around for a very long time, but it can be educational to see the process from start to finish. That’s exactly what [Frederico] shows us with his sand-cast slingshot of his own design, and it’s not bad for what he says is a first try!

First, [Frederico] makes a two-part green sand mold of the slingshot body. Green sand is a sand and clay mix, and is only green in the sense that it is wet or “raw” and not further processed. After the mold is made, it’s time to melt aluminum in the propane-powered furnace, and the molten aluminum is then poured into the mold.

After cooling, [Frederico] breaks up the sand to reveal the rough cast object. There is post-processing to do in the form of sprues to cut and some flashing around the seams to remove, but overall it looks to have turned out well. You can watch the whole process in the video, embedded below.

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Emotigun Sends A Stinging Message

May 15, 2019 by 11 Comments

Emojis, the graphical descendants of textual emoticons, are everywhere these days. They’re commonly used on social media platforms as a way of indicating a basic emotional response to a post. That wasn’t enough for [Tadas Maksimovas], who built the Emotigun to really get the point across.

Fundamentally, the Emotigun is akin to a Gatling cannon for small foam emojis. Firing over ten rounds per second, it’s built primarily out of wood, using Precise anti-cold rubber bands to fling its ammunition at targets. This was a practical choice, as the original Thera-Band green rubber tubes became inelastic in the cold temperatures of the testing environment. The finer details of the build are laid out in a document for those eager to know more.

The build was a team effort, with many pitching in, and even [Jorg Sprave] lending his expertise to the build. Given [Jorg]’s expertise, we’re not surprised the final result is so impressive. Reports are that filming the machine in action was quite an ordeal, with [Tadas] taking over 200 rounds to the face during the course of the shoot. Video after the break.

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Rey’s Blaster Shoots Glow-in-the-Dark Bullets

May 24, 2018 by 10 Comments

Youtuber and rubber band enthusiast [JoergSprave] is a big fan of Star Wars, and he loved the look of the blaster that Han Solo gave to Rey. He’d seen a few replicas of Rey NN-14 gun, but hadn’t seen any that actually fired anything, so he set out to make one that did.

The build itself is from plywood, with a paint job to make it look like an old blaster. What makes the build really cool is the bullets used: glow sticks! [Joerg] created space in the magazine for three glow sticks, so you’ve got a couple of shots before you have to reload. Crack ’em, load them up and then fire away!

The glow sticks give the blaster fire a great look (especially in the dark!) and it’s really easy to find the shots after you’ve fired them. We’ve featured [Joerg]’s builds a few times on the site, and his build videos are a lot of fun. Check out his compressed air crossbow bolt gatling gun, or his machete shooting slingshot.

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Sable-Machined Slingshot Is A Composite Marvel

November 4, 2017 by 9 Comments

Armed with an overseas CNC machine retrofitted with custom electronics, [Eric] has taken to wowing us with his suite of home-fabricated slingshots. In a more recent stint, he’s just polished off his Enzo Carbon Fiber Hydra Slingshot, complete with a build log that’s loaded with step-by-step insights.

[Eric’s] build started with a few carbon panels laying dormant in his shop for half a year. After epoxying two of these boards together for added thickness, he machines them down with his retrofitted Sable-2015 “Lunchbox CNC.” His final product accepts a few press-fit inserts, a few more machined ABS edge pieces for aesthetics, and behold: a professional slingshot that’s about as beautiful as it is dangerous.

Although the Sable-2015 CNC machine (made in Taiwan) isn’t a frequent flyer here on Hackaday, it had dozens of proud owners on a few hobby machinist forums that will rave about its wares. We’re proud to see a small-but-sturdy machine that we could carry one-handed be put to such delicate work.

[Eric] could’ve had us with his Lunchbox CNC Instructable, but he’s taken his craftsmanship to the next level by leveraging his homebrew tools and living the bootstrapped-machine-shop narrative. Slingshots don’t land here too often on these pages, but if you’re hungry for another machine monster, have a look at [Dennis the Menace’s] Triple Threat.

Full-Auto Crossbow Rocks And Rolls On Rubber Bands And Electric Drill

January 11, 2017 by 26 Comments

You’ve got to enjoy any project where the hacker clearly loves what he or she is doing. And when the project is as cool as a motor-driven, rubber band powered, fully automatic crossbow, it’s hard not to laugh along.

A full-auto crossbow is no mean feat, and it took a man with a love for rubber-powered firearms to get it right. [JoergSprave]’s design is based on a rack-and-pinion system and executed mainly in plywood. The main pinion gear is a composite of aluminum and wood, in a bid to increase the life of the mechanism and to properly deal with the forces involved. The pinion, turned by a powerful electric drill, drives the rack back and locks the carrier under the 30-bolt magazine. A rubber-powered follower forces a bolt down and a cam on the pinion trips the sear, the bolt is fired and the cycle continues.

We slowed the video down a bit and it looked to us like the cyclical rate of fire was about 7 rounds per second, or a respectable 420 rounds per minute. Pretty powerful, too, and the accuracy isn’t bad either.

We’ve seen [Joerg]’s inventions before, like this soda bottle Gatling arrow launcher, or his ridiculous machete launcher. We hope he keeps having fun and letting us watch.

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Your Fingers Will Never Leave Your Hands With This Firecracker Launcher

January 5, 2016 by 25 Comments

Who doesn’t like to ring in the New Year with explosives? But speaking from personal experience – I can neither confirm not deny nearly blowing my hand off once with a small dry-ice grenade – a hands-off way to launch your fireworks can be a plus, in which case you might want to check out this automatic firecracker launcher.

[Valentin]’s build has all the earmarks of an inspired afternoon of hasty hacking. Mostly built of wood and hot glue, there’s a feed ramp for fresh ammo and an elastic-powered sled on a ramp. Fireworks are metered onto the sled with one turn of a small gear motor, the fuse is light by a butane torch, and another gear motor pulls the sled back and launches the firecracker. The launch is somewhat anemic – perhaps some stouter rubber bands or latex tubing would provide a little more oomph. But it’s still a fun build with plenty of potential for improvement – perhaps something along the lines of this automated beer catapult?
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