Making a Crossbow for the Zombie Apocalypse

Curious if he could, [Gignathiosis] decided he wanted to try building his own crossbow. So he did.

He built the entire weapon using hand-tools, minus a drill for the holes, though he could have gotten a brace for that bit. The most impressive part is that he used a hacksaw to carve up a block of aluminum into the trigger release — a job normally done by a mill. The only modern components on the bow is the limb (which he ordered off Amazon) and a bit of tactical rail for his scope. The end result is a gorgeous hand-made cross-bow.

There’s just something so satisfying about manufacturing old technology using hand tools. It probably has something to do with the thought that, if you ended up back in time somehow, you could use your 21st century knowledge as a hacker to change the world… and maybe become a ruler — or a magician — as long as you don’t do something that results in your entire existence vanishing.

Though if you really wanted to mess up history — take back a fully-automatic crossbow with you instead.

3D Printed Gun is Off the Rails

There are certain topics that cause people to have knee-jerk reactions: Try asking a crowd which Star Trek was best or–around here–take a stance for or against the Arduino and you’ll see what we mean. Certainly people polarize quickly when you talk about a 3D printed gun. However, if anyone can sneak [xtamared’s] 3D printed rail gun through airport security, then some guards will have to be fired. It looks like a cool prop from a bad movie, but (as you can see in the videos below) it can project a conductive slug into a decidedly low-tech target.

There aren’t many build details, although you can deduce a few things from the pictures and the captions. At the rear of the gun is a paintball tank that gets the slug moving before it hits the rails which further accelerate the projectile. The electric part is Arduino-based and the very prominent capacitors at the front end can deliver 1800 joules of energy (and add 20 pounds of weight to the gun).

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Make A Cheap (And Dangerous) Automated Flamethrower

Nothing lights up the night like a quick blast from a flamethrower, but there is a reason why you can’t buy them in the Halloween decoration aisle at Target. They are dangerous, for fairly obvious reasons. [Erco] seems to have no particular fear of death, though, and he shows how you can build a simple flamethrower with a small candle, a servo, Arduino and a can of hairspray. Tresemme Extra Strong Hold, in particular, although we don’t think the exact type matters that much. All he did was to mount the candle in front of the hairspray, then mount the servo so the arm presses the spray head down. The candle does the rest, lighting the highly flammable propellant in the hairspray to produce the flamethrower effect. [Erco] is using four of these, which are co-ordinated to fire in time with music.

This one seems a bit risky. Servos have a habit of locking, and there is nothing stopping these from locking in the open position, or sticking there if the Arduino crashes. A relay or other switch that reverts to an off position when the power is removed would have been more suitable here. Secondly, there is no emergency off switch. [Erco] has wired the Arduino up next to the flamethrower itself, so you are going to have to reach in to disconnect it. That is risky enough, but he also tried a 4-way configuration that would have been impossible to disable in the event of a problem (shown in the accompanying images). Thirdly, there is no fire protection between the can of hairspray and the open flame, so if the spray head melts or fails from the heat, it’s game over. Finally (and most importantly), where are the fire extinguishers? We’d like to hear how you’d build this with safety in mind. Let us know in the comments below.

We’re big fans of flames and explosions: we’ve have seen a couple of Survival Research Laboratory shows and were blown away by their destructive pyrotechnics. But, as SRL head Mark Pauline said in a recent talk, “when things blow up at an SRL show, it’s on purpose”.

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Anvil Firing: Awesome or Reckless?

The English language needs a word for “awesome and dangerous simultaneously”.

We recently ran into the strange pastime of anvil shooting on YouTube (where else?). The idea is that you pack about a pound (!) of black powder between two anvils and light it up. The powder explodes, and the top anvil gets shot into the air. Hilarity ensues, if everyone’s far enough away and wearing hearing protection.

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The USB Killer, Version 2.0

There are a lot of stupid things you can do with the ports on your computer. The best example is the Etherkiller, an RJ45 plug wired directly to a mains cable. Do not plug that into a router. USB is a little trickier, but with a sufficient number of caps, anyone can build a USB killer that will fry any computer (.ru, Google Translatrix)

The USB Killer v2.0 is [Dark Purple]’s second version of this device. The first version was just a small board with a DC/DC converter, a few caps, and a FET. When plugged in to a computer, the converter would charge the caps up to -110V, dump that voltage into the USB signal wires, and repeat the entire process until the computer died. This second version is slightly more refined, and it now dumps -220V directly onto the USB signal wires. Don’t try this at home.

So, does the device work? Most definitely. A poor Thinkpad X60 was destroyed with the USB killer for purposes of demonstration in the video below. This laptop was originally purchased just for the test, but the monster who created the USB killer grew attached to this neat little laptop. There’s a new motherboard on the way, and this laptop will live again.

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Raspberry Pi Sentry Turret Is The Enemy Of All Mankind

War, huh, what is it good for? Absolutely nothing, except as an excuse to build a Raspberry Pi powered sentry turret that will track and fire upon your enemies. That’s what [Matt Desmaris] decided to do, and he has released the full details of his build.

It lacks the polished elegance of most military hardware, but what do you expect of a quick and dirty hack? It’s not shiny or ominous, but it has that killer motion-tracking feature. [Matt] is using OpenCV to detect movement from a USB webcam, two servos to pan and tilt the camera and gun and a small relay to pull the trigger. Manual control over the Interwebs is also available.

We’ve seen lots of similar builds using weaponry such as rubber bands and Nerf guns, but this one is a great start if you are interested in seeing how you can tie together tools like OpenCV and servos to create a camera that actively tracks movement.

Hacking when it Counts: GI Ingenuity

For most of us, hacking is a hobby, a pleasant diversion from reality. Yes, a lot of us work on projects which have the potential to change the world – witness the 2015 Hackaday Prize semifinalist list. But in general, almost any of us could walk away from the shop at any time without dire consequences. Indeed, that’s the reason a lot of our work benches are littered with projects started with the best of intentions but left unfinished for lack of funds, lack of interest, or lack of time. We’re free to more or less willingly shelve a project and come back to it whenever we please, or not at all.

But not everyone has that luxury. For some people, hacking is much more than a hobby – it’s a means of survival. Sometimes people are thrown into situations where they have to cobble together a solution to an immediate problem with whatever is at hand, when the penalty for failure is much higher than a cluttered bench and a bruised ego. I’ve already covered one such case, where biohacked insulin saved hundreds of lives in occupied Shanghai in WWII.

In this occasional series I’ll explore historical cases where hacking really counted; cases where lives were saved or improved by a hack performed under desperate conditions.

A Bustle in the Hedgerow

Unsurprisingly, war offers a lot of opportunities for field expedient solutions under dire circumstances, and battlefield conditions might be the most extreme example of hacking when it counts.

In the early days of the Invasion of Normandy during WWII, Allied forces were having a difficult time dealing with the bocage terrain of northern France. A mixture of pasture and woodland, the Normandy bocage was a natural killing field for Allied tanks because the woodlands took the form of hedgerows – earthen dikes topped with thick tangles of brush. Hedgerows separated pastures and kept livestock controlled, but also made things tough on infantry and mechanized cavalry alike. Climbing the steep hedgerows exposed the vulnerable bottom hull of the tanks to enemy fire, and waiting for engineers to demolish the hedgerows with explosive made them sitting ducks for German artillery. The Allied advance was seriously hampered by the hedgerows, and both men and materiel were being winnowed down from fixed German positions chosen specifically to take advantage of the bocage terrain.

curtis cullin
Sgt. Curtis G. Culin (source: Cranford (NJ) Patch)

Enter Sgt. Curtis Grubb Culin III. Sgt. Culin, a tanker himself, was acutely aware of how vulnerable he was in his Sherman M4. The hedgerows were the problem, one apparently known to Allied command prior to the invasion for which no provision had been made. In the tradition of soldiers at the front of every battle throughout history, Sgt. Culin and his fellow tankers had to improvise a solution.

While kicking around ideas, one of the men suggested setting saw teeth on the front of a tank to cut through the hedgerows. He later attributed the comment to “A Tennessee hillbilly named Roberts”, and it was met with general laughter from the group as a crackpot scheme. But Sgt. Culin saw the potential in the idea, and began to develop it into a prototype.

Yanks_of_60th_Infantry_Regiment_advance_into_a_Belgian_town_under_the_protection_of_a_heavy_tank._-_NARA_-_531213
Rhino-equipped tank (source: Wikipedia)

Raw materials for his prototype were not hard to come by. Czech hedgehogs, giant anti-tank barriers made of crossed steel beams, still littered the Normandy beaches. The failed German defenses were harvested with a cutting torch and welded to the underside of a tank to form a series of “tusks” across the hull between the tracks. Equipped with these tusks, the tank could now blast through the tangled roots of the brush-covered earth of the hedgerow dykes.

When demonstrated for General Omar Bradley, he was impressed enough to order them built in quantity for the tanks. Eventually the prototype became an engineered product (dubbed the “Culin Rhino Device”) that was fitted to many tanks before being shipped over from England. Rhino-equipped tanks ripped across Normandy and shredded the German battle plan, which assumed the hedgerows would funnel Allied forces through heavily defended chokepoints.

Without Sgt. Culin’s battlefield hack, and his inspiration by a hillbilly named Roberts whom history otherwise forgets, the invasion of Europe might have taken a very different course. The fact that he did the hack while under fire makes it all the more impressive, and is a perfect example of hacking when it counts.

Know of any more examples of hacking when it counts? Send us a tip for use in a future Hacking When it Counts article.

[Main image of Czech Hedgehog by Jesse CC-BY-SA 3.0]