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.
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.
Many Hackaday readers may also be familiar with the Discworld series of fantasy novels from [Terry Pratchett], and thus might recognise a weapon referred to as the Piecemaker. A siege crossbow modified to launch a hail of supersonic arrows, it was the favoured sidearm of a troll police officer, and would frequently appear disintegrating large parts of the miscreants’ Evil Lairs to comedic effect.
Just as a non-police-officer walking the streets of Ank-Morpork with a Piecemaker might find swiftly themselves in the Patrician’s scorpion pit, we’re guessing ownership of such a fearsome weapon might earn you a free ride in a police car here on Roundworld. But those of you wishing for just a taste of the arrow-hail action needn’t give up hope, because [Turnah81] has made something close to it on a smaller scale. His array of twelve mousetrap-triggered catapults fires a volley of darts made from wooden kebab skewers in an entertaining fashion, and has enough force to penetrate a sheet of cardboard.
He refers to a previous project with a single dart, and this one is in many respects twelve of that project in an array. But in building it he solves some surprisingly tricky engineering problems, such as matching the power of multiple rubber bands, or creating a linkage capable of triggering twelve mousetraps (almost) in unison. His solution, a system of bent coat-hanger wires actuated by the falling bar of each trap, triggers each successive trap in a near-simultaneous crescendo of arrow firepower.
On one hand this is a project with more than a touch of frivolity about it. But the seriousness with which he approaches it and sorts out its teething troubles makes it an interesting watch, and his testing it as a labour-saving device for common household tasks made us laugh. Take a look, we’ve put the video below the break.
We like cheap FPGA boards. It isn’t just that we’re cheap — although that’s probably true, too — but cheap boards are a good way to get people started on FPGAs and we think more people should be using FPGAs more often. One inexpensive board is the Max-1000 from Trenz and Arrow. At $29, it is practically an impulse buy. [ZipCPU] did a great write up on his experience using the board. He found that some of it was good, some was bad, and some was just plain ugly. Still, for $30, it seems like this might be a nice board for some applications or for getting started.
Billed an IoT Maker Board, the tiny board sports a Intel (formerly Altera) MAX10 device with 8,000 logic elements, a USB programming interface onboard, 8 MB of SDRAM, and both PMOD and Arduino MKR headers. The MAX10 has an analog to digital conversion block (with an analog mux for up to nine channels) and the ability to host a 32-bit soft controller onboard, too.
As it turns out, it’s not feasible to print an entire crossbow yet. But [Dan]’s crossbow build does a good job of leveraging what a 3D printer is good at. Most of the printed parts reside in the crossbow’s trigger group, and the diagrams in the write-up clearly show how the trigger, sear and safety all interact. Particularly nice is the automatic nature of the safety, which is engaged by drawing back the string. We also like the printed spring that keeps the quarrel in place on the bridle, and the Picatinny rail for mounting a scope. Non-printed parts include the aluminum tubes used in the stocks, and the bow itself, a composite design with fiberglass rods inside PVC pipe. The video below shows the crossbow in action, and it looks pretty powerful.
Actually, we’ll partially retract our earlier dismissal of entirely 3D-printed crossbows, but [Dan]’s version is a lot more practical and useful than this model. And for a more traditional crossbow design, check out this entirely hand-made crossbow.
Time was when a lad in need of a ranged weapon would hack a slingshot together out of a forked tree branch and a strip of inner tube. Slingshot design has progressed considerably since [Dennis the Menace]’s day, but few commercially available slingshots can match up to the beauty and functionality of this magnificently machined multipurpose handheld weapon system.
Making it clear in his very detailed build log that this is but a prototype for a design he’s working on, [Gord] has spared little effort to come up with a unique form factor that’s not only functional as a slingshot, but also provides a few surprises: a magazine that holds nine rounds of ammo with magnets; knuckle protection on the hand grip that would deal a devastating left hook; and an interchangeable base that provides a hang loop or allows mounting a viciously sharp broadhead hunting arrow tip for somewhat mysterious purposes. There’s plenty to admire in the build process as well – lots and lots of 6061 billet aluminum chips from milling machine and lathe alike. All told, a nice piece of craftsmanship.
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.
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.