Machine-Vision Archer Makes You The Target, If You Dare

We’ll state right up front that it’s a really, really bad idea to let a robotic archer shoot an apple off of your head. You absolutely should not repeat what you’ll see in the video below, and if you do, the results are all on you.

That said, [Kamal Carter]’s build is pretty darn cool. He wisely chose to use just about the weakest bows you can get, the kind with strings that are basically big, floppy elastic bands that shoot arrows with suction-cup tips and are so harmless that they’re intended for children to play with and you just know they’re going to shoot each other the minute you turn your back no matter what you told them. Target acquisition is the job of an Intel RealSense depth camera, which was used to find targets and calculate the distance to them. An aluminum extrusion frame holds the bow and adjusts its elevation, while a long leadscrew and a servo draw and release the string.

With the running gear sorted, [Kamal] turned to high school physics for calculations such as the spring constant of the bow to determine the arrow’s initial velocity, and the ballistics formula to determine the angle needed to hit the target. And hit it he does — mostly. We’re actually surprised how many on-target shots he got. And yes, he did eventually get it to pull a [William Tell] apple trick — although we couldn’t help but notice from his, ahem, hand posture that he wasn’t exactly filled with self-confidence about where the arrow would end up.

[Kamal] says he drew inspiration both from [Mark Rober]’s dart-catching dartboard and [Shane Wighton]’s self-dunking basketball hoop for this build. We’d say his results put in him good standing with the skill-optional sports community.

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Slick DIY Compound Bow Uses Coiled Springs, Toothbrush Heads

Compound bows (unlike recurve bows, their more mechanically-simple relatives) use a levering system with pulleys and spring tension to grant the user a mechanical advantage. We’re not exactly sure what to call [Zünder’s] bow design. He shared his unconventional take on a DIY bow that uses coiled springs as well as some other unique features.

Toothbrush heads and 3D printing make an enclosed, bristle-supported arrow rest.

What we really dig about [Zünder]’s design is how easy it is to grasp how it all works. As he demonstrates using the bow, the way the levers, pulleys, and spring tension all work together is very clear. The 3D-printed quiver and arrow rest are nice added touches, and we especially love the use of three toothbrush heads to provide contained support for a nocked arrow. The ring of bristles are sturdy enough to easily support the shaft, and don’t interfere with the arrow’s fletching.

[Zünder] has a photo gallery with a few additional photos and closeups, and you can watch him demonstrate his bow in the video embedded below.

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Make Your Own Compound Bow From PVC Pipe

Have you ever wanted to make your own compound bow for fun or even fishing? [New creative DIY] shows us how in their YouTube video. Compound bows are very powerful in comparison to their longbow grandparents, relying on the lever principle or pulleys. meaning less power exertion for the same output.

Compound bows can be really sophisticated in design using pulleys and some exotic materials, but you can make your own with a few nuts and bolts, PVC pipe, string and a tyre inner tube. The PVC pipe can be melted into shape using a heat source such as a portable stove or even a blow torch, and once you have shaped your bow you will want to put a small piece of pipe at both ends with a nut and bolt. Then you can use rubber to give the flexibility your bow needs to shoot arrows, using the tyre inner tube cut to the right size. A piece of string for the ends of your arrows to rest on is then all you need, attach this to either end of your pipe and you should have a DIY PVC compound bow ready for shooting arrows. Alternatively you could always make a recurve bow out of skis.

–Update [Leithoa] in the comments has pointed out this is neither a bow nor a compound and that they are often confused. This is actually a slingshot, of sorts.–
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Making A Bow From Scratch

bow

With Hackaday’s new handmade category we have the option of covering a wide range of builds – everything from jet engines designed on paper and built on manual machines, to old-world crafts made with the most primitive tools. This time, we’ll be looking at making a longbow from scratch, the work of [Billy Berger], a project that covers everything from selecting a tree to tillering a bow to make the best possible weapon.

European-inspired longbows are usually constructed out of yew, but in [Billy]’s native east Texas yew is a little hard to come by. He eventually selected a small Osage orange tree for his bow, stripped the bark, split the log, and started crafting his handmade bow.

The most important part of making a bow is ensuring the back of the bow consists of only one growth ring. With a drawknife, [Billy] carefully planed down the back of the bow so only one of the tree’s growth rings was visible, then began shaping the belly and sides of the bow.

Wood is a natural material, and when freshly cut contains a lot of moisture. As [Billy] was working on his bow, some of the moisture left his piece of Osage, leading to some twists and turns in the lumber. There’s a solution to this that mankind has been doing for millennia – fire bending the wood. By covering the wood in some sort of animal fat ([Billy] used olive oil), you can hold a piece of wood over a small frame without scorching. Using the crook of a tree as a vice, [Billy] twisted the wood, giving him a perfectly straight bow.

There’s an amazing amount of work that went into this bow, not surprising given that [Billy] is only using hand tools and primitive woodworking methods. Still, the completed bow is a work of art and a masterpiece of craftsmanship. You can check out all four parts of [Billy]’s demo below.

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Recurve Bow Make From Wood And Skis

bow-made-from-ski

A little face protection is a great idea when first testing out your homemade bow. [Austin Karls] made this recurve bow during what he calls an engineer’s Spring break.

He settled on the idea after seeing a few other projects like it on Reddit. After first drawing up a plan he headed down to the shop to cut out the wooden riser (the middle part of a bow). Unlike traditional recurve bows this is made up of three parts. Traditionally you would laminate different types of wood to achieve the flexibility and tension levels desired. But [Austin] went with a synthetic material: the tips of two skis. Each were cut to the final length and affixed to the riser with a pair of bolts.

After a few test shots he gained confidence in the design and did away with the face mask. Now if you’re in the market to take your existing bow and add some firepower to it you’ll want to look in on this shotgun enhanced compound bow.

[Thanks Schuyler]

Virtual Archery Game Makes Practicing Convenient, Safe, And Inexpensive

Virtual-Archery

Inspired by playing The Legend of Zelda video game series, Cornell University students [Mohamed Abdellatif] and [Michael Ross] created a Virtual Archery game as their ECE 4760 Final Project.   The game consists of a bow equipped with virtual arrows and a target placed about 20 ft away. The player has three rounds to get as high of a score as possible. A small display monitor shows the instructions, and an image of where the shot actually hit on the target.

Pressing a button on the front of the bow readies a virtual arrow. A stretch sensor communicates with a  microcontroller to determine when the bow string has been drawn and released.  When the bow is drawn, a line of LEDs lights up to simulate a notched arrow. The player aims, and factors in for gravity. An accelerometer calculates the orientation of the bow when fired. The calculated shot is then shown on the display monitor along with your score.

This immediately makes me think of Laser Tag, and feels like a product that could easily be mass marketed. I’m surprised it hasn’t been already. Good work guys.

[via Hackedgadgets]

Check out the video demonstration after the break:

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12 Gauge Shotgun Bow: Real Or Fake?

It’s time once again for everyone’s favorite comments section game: Real or Fake? This week we’re looking into this 12 gauge shotgun bow. Why use arrows when you can fire shells? This gentleman has apparently removed the stock of a 12 gauge shotgun and positioned the barrel as if it were an arrow. When he releases the bowstring the gun fires.

Take a look a the quick clip after the break and let us know what you think. We’ve fired a 12 gauge and the kick is surprising. Although the sound matches in this video, we think he’s got arms of steel if he can control the weapon that well with one outstretched arm. But then again, perhaps our arms are just too wimpy from all that intricate surface mount soldering we do.

If you’ve missed out on this game in the past be sure to look back on the last couple features.

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