Watch The Diesel Effect In Ballistic Gelatin

October 13, 2016 by Donald Papp 41 Comments

A striking video appears to demonstrate an explosion via the diesel effect in clear ballistic gel. The diesel effect or “dieseling” refers to when a substance ignites from the effects of pressure, and it’s the operating principle behind the gadgets known as Fire Sticks or Fire Pistons.

Ballistic gel is a broad term referring to a large chunk of dense gel generally used in firearms-related testing to reliably and consistently measure things like bullet deformation, fragmentation, and impact. It’s tough, elastic, and in many ways resembles a gigantic gummi bear. Fans of Mythbusters (or certain DIY railguns) will recognize the stuff. Water-based blocks made with natural gelatin can be easily made at home, but end up with a yellow-brown color and have a limited shelf life due to evaporation. Clear blocks exist that are oil-based and don’t dry out like the water-based ones. It’s one of these that is in the embedded animation below.

Slow motion video capture is a natural companion to just about anything that you’d need ballistic gel for, and good thing — because the video captured what appears to be a diesel effect! The block is hit with a bullet, and as the bullet rapidly expands and dumps its energy into the gel, a cavity expands rapidly. During this process, some of the (oil-based) material in the cavity has been vaporized. After the expanded bullet exits (to the right of the gif above but easier to see in the video below), the cavity in the block begins to collapse. The resulting pressure increase appears to ignite the vaporized material, which explodes with a flash followed by some exhaust.

This effect has been observed in ballistic gel before, but this video shows a particularly clear ignition, followed by a secondary expansion of the cavity, then a flatulent-ish ejection of exhaust as the cavity collapses. If nothing else, it’s a very striking effect clearly captured on film. Slow-motion capture of destructive forces makes visible many things that would otherwise happen too quickly to perceive.

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3D Printed Nozzles Turbocharge Microsphere Production

October 13, 2016 by Donald Papp 14 Comments

Researchers at MIT have used 3D printing to open the door to low-cost, scalable, and consistent generation of microencapsulated particles, at a fraction of the time and cost usually required. Microencapsulation is the process of encasing particles of one material (a core) within another material (a shell) and has applications in pharmaceuticals, self-healing materials, and dye-based solar cells, among others. But the main problem with the process was that it was that it was slow and didn’t scale, and it was therefore expensive and limited to high-value applications only. With some smart design and stereolithography (SLA) 3D printing, that changed. The researchers are not 3D printing these just because they can; they are printing the arrays because it’s the only way they can be made.

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Skynet Takes Over…Academia?

October 13, 2016 by Al Williams 8 Comments

A telescope isn’t an unusual thing to own if you are technically inclined. You might have even made one, at some point. However, despite improvements in optical technology and computer aiming devices, your four to twenty-inch instrument is never going to show you images like you see from big giant telescopes. The problem is, going really big requires a lot of investment in time, money, and sometimes even real estate. The big scopes get buildings constructed for them, and in exotic locations; why would you build a 24-inch scope only to try to see through the light pollution in your backyard?

Here’s an idea: take an astronomy class at a college and use their big telescope. Well, who has the time and money for that? Actually, you do. Skynet is a global network of telescopes headquartered at the University of North Carolina. As part of their mandate, they offer several tuition-free astronomy classes over the Internet. The best part? You also get free time on Skynet’s telescopes to complete your class assignments. There is a small fee (between $45 and $65) to a “benefit corporation” to administer assignments. You do get a certificate upon graduation. If you don’t want to do the assignments and you don’t want a certificate, you can still “take” the classes by simply watching them on YouTube. You can see one of the classes in the video below.

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From CRT TV To All-In-One Console

October 13, 2016 by Jenny List 8 Comments

When the Raspberry Pi first appeared there was some excitement among Raspberry Jam attendees at the prospect of a computer with a video output on a board small enough to be concealed inside a TV. But while the idea is a good one the prospect of poking around among the high voltages of an older CRT model has meant that surprisingly few such ideas turned into reality.

One person who made the idea into a reality was [Jon], who took a [Dora] The Explorer branded CRT/DVD combo in a fetching shade of red and turned it into an all-in-one retro console gaming system with an embedded Raspberry Pi.

This is however not merely a Pi stuffed inside the rear casing with a few holes for cables, instead he took away the substantial part of the DVD mechanism and mounted his Pi safely in a plastic box. Some USB extension cables bring all four USB sockets to the front panel through the DVD slot with a bit of Sugru to hold them in place. An HDMI panel-mount extension goes to the TV’s rear connector panel, as does a power switch for the Pi which is wired to a USB charger mounted on a trailing mains socket inside the case. The composite video from the Pi is wired to the TV’s AV in video socket.

We don’t blame [Jon] for not looking at the TV’s power rails to find power for his Pi, though a TV of this recent age would have safely mains-isolated rails that’s still a task fraught with hazards. The resulting unit is a high quality retro console, and as a final touch he’s given it a Nintendo logo and some storage for his gamepads on the rear.

We’ve had a few CRTs with integrated computers before here at Hackaday, but not all have been as they seemed. This Pi for instance sat in a vintage Singer TV, but the CRT was replaced with a modern LCD. Our favourite though it this Chromecast driving a 1978 GE model.

Too Good To Throw Away: Dealing With An Out-Of-Control Junk Hoard

October 13, 2016 by Jenny List 193 Comments

There it was, after twenty minutes of turning the place over, looking through assorted storage boxes. A Thinwire Ethernet network. About the smallest possible Thinwire Ethernet network as it happens, a crimped BNC lead about 100mm long and capped at each end by a T-piece and a 50 ohm terminator. I’d been looking for a BNC T-piece on which to hook up another terminator to a piece of test equipment, and I’d found two of them.

As I hooked up the test I wanted to run I found myself considering the absurdity of the situation. I last worked somewhere with a Thinwire network in the mid 1990s, and fortunately I am likely to never see another one in my life. If you’ve never encountered Thinwire, be thankful. A single piece of co-ax connecting all computers on the network, on which the tiniest fault causes all to fail.

So why had I held on to all the parts to make one, albeit the smallest possible variant? Some kind of memento, to remind me of the Good Old Days of running round an office with a cable tester perhaps? Or was I just returning to my past as a hoarder, like a Tolkienic dragon perched atop a mountain of electronic junk, and not the good kind of junk?

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Blinking An LED – Extreme Edition

October 13, 2016 by Nava Whiteford 57 Comments

This hacker’s video on blinking LEDs never got the recognition it deserves. At the time of writing clocking in at just 61 views, but it is indeed a work of art. Just trust me, scroll to the bottom of the article and watch it, you wont be disappointed.

Not convinced? OK, let me tell you about it and the world it has opened up in the Japanese maker scene. We’ve all blinked an LED. Maybe it was just to test a microcontroller, like the simplest Arduino example.

Or we’ve been a tad more old school and used the classic 555 to do it. Or maybe like me, you went through a phase of hacking together Phase Shift and other oscillators because well… it’s fun!

But [Junichi AKITA] has more extreme tastes, deciding that a custom IC layout is the way to go. [Junichi] designed a ring oscillator composed of flip-flops, then hand laid out each MOSFET placing each layer exactly where it should be fabricated.

The resulting design was then fabricated by an academic shuttle service in Japan (a bit like the well known MOSIS service). The result is a tiny circuit in the top right corner of the IC. Which of course [Junichi] then had to wirebond (check the video for a cool 1980s style Westbond machine which are still hugely popular in Japan).

IC Layout… by hand!

Optical image of the fabricated circuit.

[Junichi] bonded the die directly to a PCB (COB). I assume, purely for irony, a 555, and ATtiny based oscillator were also laid out on the board.

I guess you might have a couple of lingering questions. First you’ll likely bemoan your lack of your own fabrication facility (I’m still eyeing those used 1 micron fab lines that crop up on eBay from time to time). And secondly you might be asking yourself… why?

Both these questions are somewhat answers by the MakeLSI project. This growing project in Japan seems to have opened up semiconductor fabrication to all kinds of projects.

While my Japanese isn’t good enough to fully understand what’s happening it’s clear there are many awesome projects going on. Including joys such as IC layouts designed in vector graphics packages (Inkscape) and die images packed with interesting layouts, anime characters and QR codes.

For more awesome images and information (unfortunately all in Japanese) you can check them out on Facebook or on their homepage.

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Hackathon Alert: Clean Tech At TVCoG

October 13, 2016 by Dan Maloney 2 Comments

At Hackaday, we get notified of a lot of the cool events going on in hackerspaces all around the world. We’d like to keep you informed too, just in case there’s something going on in your neighborhood.

So we’re going to start running a weekly column on Saturdays that groups together all of the upcoming week’s exceptional events and noteworthy gatherings. If your hackerspace has something going on, tell us about your event on or around the preceding Wednesday. We’ll see your space in on Hackaday!
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