The Strange Physics Of Curling

It turns out that curling involves some complex physics. [Destin] of Smarter Every Day has jumped in to find out why scientists on opposite sides of the Atlantic disagree about why curling stones curl.

If you’ve been watching the Olympics, you’ve probably seen some curling, the Scottish sport of competitively pushing stones on ice. As the name implies, curling stones don’t go straight. The thrower pushes them with a bit of rotation, and the stones curve in the direction they are rotating. This is exactly the opposite of what one would expect — try it yourself with an inverted drinking glass on a smooth table.  The glass will curl opposite the direction of rotation. Clockwise spin will result in a curl to the left, counterclockwise in a curl to the right.

The cup makes sense when you think about the asymmetrical friction involved. The cup is slowing down, which means more pressure on the leading edge. The rotating leading edge pushes harder against the table and causes the cup to curl opposite the direction of rotation.

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Milspec Teardown: CP-142 Range Computer

As some of my previous work here at Hackaday will attest to, I’m a big fan of World War II technology. Something about going in with wooden airplanes and leaving with jet fighters and space capable rockets has always captivated me. So when one of my lovingly crafted eBay alerts was triggered by something claiming to be a “Navy WWII Range Computer”, it’s safe to say I was interested.

Not to say I had any idea of what the thing was, mind you. I only knew it looked old and I had to have it. While I eagerly awaited the device to arrive at my doorstep, I tried to do some research on it and came up pretty much empty-handed. As you might imagine, a lot of the technical information for hardware that was developed in the 1940’s hasn’t quite made it to the Internet. Somebody was selling a technical manual that potentially would have covered the function of this device for $100 on another site, but I thought that might be a bit excessive. Besides, where’s the fun in that?

I decided to try to decipher what this device does by a careful examination of the hardware, consultation of what little technical data I could pull up on its individual components, and some modern gear. In the end I think I have a good idea of how it works, but I’d certainly love to hear if there’s anyone out there who might have actually worked with hardware like this and could fill in any blanks.

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Rejecting Microsoft’s Phaseout Of The Kinect

You might not be aware unless you’re up on the latest gaming hardware, but Microsoft is trying to kill the Kinect. While the Xbox One famously included it as a mandatory pack-in accessory at launch (this was later abandoned to get the cost down), the latest versions of the system don’t even have the proprietary port to plug it in. For a while Microsoft was offering an adapter that would let you plug it into one of the console’s USB ports, but now even that has been discontinued. Owners of the latest Xbox One consoles who still want to use the Kinect are left to find an adapter on eBay, where the prices have naturally skyrocketed.

Recently [Eagle115] decided to open up his Kinect and see if he couldn’t figure out a way to hook it up to his new Xbox One. The port on the Kinect is a USB 3.0 B female, but it requires 12V to operate. The official Kinect adapter took the form of a separate AC adapter and a “tap” that provided the Kinect with 12V over USB, so he reasoned he could pop open the device and provide power directly to the pads on the PCB.

[Eagle115] bought a 12V wall adapter and a USB 3.0 B cable and got to work. Once the Kinect was popped open, he found that he needed to supply power on pin 10 (which is helpfully labeled on the PCB). There’s just enough room to snake the cable from the AC adapter through the same hole in the case where the the USB cable connects.

With the Kinect getting 12V from the AC adapter, the Xbox has no problem detecting it as if you were using the official adapter. At least for now, they haven’t removed support for the Kinect in the Xbox’s operating system.

The Kinect has always been extremely popular with hackers (it even has its own category here on Hackaday), so it’s definitely sad to see that Microsoft is walking away from the product. The community will no doubt continue pulling off awesome hacks with it; but it’s looking increasingly likely we won’t be getting a next generation Kinect.

[via /r/DIY]

Whatever Happened To The Desktop Computer?

If you buy a computer today, you’re probably going to end up with a laptop. Corporate drones have towers stuffed under their desks. The cool creative types have iMacs littering their open-plan offices. Look around on the online catalogs of any computer manufacturer, and you’ll see there are exactly three styles of computer: laptops, towers, and all-in-ones. A quick perusal of Newegg reveals an immense variety of towers; you can buy an ATX full tower, an ATX mid-tower, micro-ATX towers, and even Mini-ITX towers.

It wasn’t always this way. Nerds of a sufficient vintage will remember the desktop computer. This was, effectively, a tower tilted on its side. You could put your monitor on top, negating the need for a stack of textbooks bringing your desktop up to eye level. The ports, your CD drive, and even your fancy Zip drive were right there in front of you. Now, those days of desktop computers are long gone, and the desktop computer is relegated to history. What happened to the desktop computer, and why is a case specifically designed for a horizontal orientation so hard to find?

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Arduino Keyboard Is Gorgeous Inside And Out

While the vast majority of us are content to plod along with the squishy chiclet keyboards on our laptops, or the cheapest USB membrane keyboard we could find on Amazon, there’s a special breed out there who demand something more. To them, nothing beats a good old-fashioned mechanical keyboard, where each key-press sounds like a footfall of Zeus himself. They are truly the “Chad” of the input device world.

But what if even the most high end of mechanical keyboards doesn’t quench your thirst for spring-loaded perfection? In that case, the only thing left to do is design and build your own. [Matthew Cordier] recently unveiled the custom mechanical keyboard he’s been working on, and to say it’s an elegant piece of engineering is something of an understatement. It may even look better inside than it does on the outside.

The keyboard, which he is calling z.48, is based around the Arduino Pro Micro running a firmware generated on kbfirmware.com, and features some absolutely fantastic hand-wiring. No PCBs here, just a rainbow assortment of wire and the patience of a Buddhist monk. The particularly attentive reader may notice that [Matthew] used his soldering iron to melt away the insulation on his wires where they meet up with the keys, giving the final wiring job a very clean look.

Speaking of the keys, they are Gateron switches with DSA Hana caps. If none of those words mean anything to you, don’t worry. We’re through the Looking Glass and into the world of the keyboard aficionado now.

Finally, the case itself is printed on a CR-10 with a 0.3 mm nozzle and 0.2 mm layers giving it a very fine finish. At 70% infill, we imagine it’s got a good deal of heft as well. [Matthew] mentions that a production case and a PCB are in the cards for the future as he hopes to do a small commercial run of these boards. In the meantime we can all bask in the glory of what passes for a prototype in his world.

We’ve seen some exceptionally impressive mechanical keyboards over the years, including the occasional oddity like the fully 3D printed one and even one that inexplicably moves around. But this build by [Matthew] has to be one of the most elegant we’ve ever come across.

Hovercraft Of The Future

We think of hovercraft as a modern conveyance. After all, any vision of the future usually includes hovercraft or flying cars along with all the other things we imagine in the future. So when do you think the hovercraft first appeared? The 1960s? The 1950s? Maybe it was a World War II development from the 1940s? Turns out, a human-powered hovercraft was dreamed up (but not built) in 1716 by [Emanuel Swedenborg]. You can see a sketch from his notebook below. OK, that’s not fair, though. Imagining it and building one are two different things.

[Swedenborg] realized a human couldn’t keep up the work to put his craft on an air cushion for any length of time. Throughout the 1800s, though, engineers kept thinking about the problem. Around 1870, [Sir John Thornycroft] built several test models of ship’s hulls that could trap air to reduce drag — an idea called air lubrication, that had been kicked around since 1865. However, with no practical internal combustion engine to power it, [Thornycroft’s] patents didn’t come to much. In America, around 1876 [John Ward] proposed a lightweight platform using rotary fans for lift but used wheels to get forward motion. Others built on the idea, but they still lacked the engines to make it completely practical.

But even 1940 is way too late for a working hovercraft. [Dagobert Müller] managed that in 1915. With five engines, the craft was like a wing that generated lift in motion. It was a warship with weapons and a top speed of around 32 knots, although it never saw actual combat. Because of its physical limitations it could only operate over water, unlike more modern craft.

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Mechanisms: Bearings

They lie at the heart of every fidget spinner and in every motor that runs our lives, from the steppers in a 3D printer to the hundreds in every car engine. They can be as simple as a lubricated bushing or as complicated as the roller bearing in a car axle. Bearings are at work every day for us, directing forces and reducing friction, and understanding them is important to getting stuff done with rotating mechanisms.

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