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11 Articles

Hacking When It Counts: Surgery Fit To Save A Future King

September 20, 2021 by 43 Comments

When we picture the Medieval world, it conjures up images of darkness, privations, and sickness the likes of which are hard to imagine from our sanitized point of view. The 1400s, and indeed the entirety of history prior to the introduction of antibiotics in the 1940s, was a time when the merest scratch acquired in the business of everyday life could lead to an infection ending in a slow, painful death. Add in the challenges of war, where violent men wielding sharp things on a filthy field of combat, and it’s a wonder people survived at all.

But then as now, some people are luckier than others, and surviving what even today would likely be a fatal injury was not unknown, as one sixteen-year-old boy in 1403 would discover. It didn’t hurt that he was the son of the king of England, and when he earned an arrow in his face in combat, every effort would be made to save the prince and heir to the throne. It also helped that he had the good fortune to have a surgeon with the imagination to solve the problem, and the skill to build a tool to help.

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Building An Electronic Tester For Measuring Arrow Stiffness

July 26, 2021 by 1 Comment

When shooting archery, if you want to be accurate, you need arrows of uniform specification and quality. One important part of this is making sure each arrow has a spine of similar stiffness. Traditionally, this is checked in a very analog way by using weights and measuring deflection of the arrow spine, but it can be done electronically too with this tester from [dvd8n].

The principle of operation is simple. The arrow is held up by two supports, 28 inches apart. The user then presses down in the center of the arrow, deflecting it by a 1/2 inch where itreaches a stop , and load cells at either end of the tester measure the force required to deflect the arrow by the set amount.

It allows arrows to be electronically measured in a fashion that is compatible with existing standards for measurement. The Arduino hardware which measures the load cells can also easily run conversion maths to display the arrow’s measured stiffness in whatever common spine measurement standard is desired. The system can also weigh the arrows, a useful thing to know for the home fletcher.

It’s a tidy build and one that should prove useful when [dvd8n] is building out their next quiver. We’ve seen other capable DIY archery hacks before, too. If you’ve got your own, drop us a line!

 

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

June 30, 2021 by 6 Comments

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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