DIY Electron Accelerator

August 30, 2011 by Kevin Dady 26 Comments

Reader [Xellers] sent in his newest instructable: DIY Electron Accelerator: A Cathode Ray Tube in a Wine Bottle. While not exactly what you might think of a cathode ray tube, the basics are in place. A wine bottle is used as a vacuum chamber and a 9kv neon transformer is attached to a stopped in the top. A cathode is placed mid way, the air is sucked out with a pump, and high voltage is applied.

Naturally as more air gets pumped out the electric arc intensifies into a pretty solid plasma filling the space between the two contacts. While mixing drilled glass with a vacuum and high voltage sounds like an awesome hospital story [Xellers] does cover some safety points including the possibility of this thing putting out some nasty waves.

One thing that is not mentioned (that I saw) is this is very similar to how florescent light tubes work and without florescent material lining the chamber it will spit out quite a bit of UV light (notice germicidal UV lights are clear). So you will want to watch your eyes!

Join us after the break for a quick video.

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Installing OpenSSH On The HP TouchPad

August 26, 2011 by Mike Nathan 21 Comments

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[Russ] was lucky enough to get his hands on a deeply discounted HP TouchPad, and after hearing about the huge bounty being offered for getting Android up and running on the device, he decided to poke around and see if he could make some headway.

He started off by making a full backup copy of his file system using a tool HP has on their WebOS site, just in case anything unfortunate happened to his device in the process. He grabbed a copy of the ARM cross-compiler and set off to build a copy of OpenSSH for the TouchPad. Once he had the binaries in hand, he started what he thought would be the arduous process of getting SSH onto the TouchPad, but it turned out that it was a simple drag and drop operation.

After remounting the file system to allow write operations, he fired up the SSH daemon and hoped for the best. It worked like a charm, and while it’s a relatively small part of getting Android running on the TouchPad, every bit helps.

When Airsoft Gets Boring, Build A Coil Gun!

August 24, 2011 by Mike Nathan 30 Comments

airsoft_coilgun

Here at Hackaday, we’re all about repurposing old items you no longer use. Reader [Liquider] wrote in to share his latest creation, a coil gun built from an old Airsoft pistol.

He removed a handful of components from the pistol and installed a 800 uF/300V capacitor inside the grip. A small storage compartment was added under the barrel, which houses the AA battery he uses to drive the circuit. A modified reloading mechanism makes it easy to drop a metal projectile right in front of the coil before firing.

Once the pistol is charged up, a switch installed behind the trigger discharges the cap, creating a magnetic pulse that accelerates the metal projectile forward. [Liquider] estimates that the kinetic energy produced by the coil is 0.1 Joules, which fires of the slug at a reasonable speed.

Continue reading to see a quick video demo of the pistol in action.

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Forget That Boring Old Fire Pit, Build A Flame Tree Instead!

August 24, 2011 by Mike Nathan 12 Comments

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Maker Faire is a great event to attend not only because you get to see all sorts of cool designs and machinations, but because you can participate as well. At Maker Faire Bay Area 2011, maker [Brett Levine] put together a fun and interactive display he likes to call the DIY Flame Tree.

The concept is pretty simple, and he says everyone who participated got a pretty good kick out of lending a hand. Each participant was given a piece of copper tubing and allowed to bend, twist, and sculpt it to their liking before using a drill to add holes wherever they pleased. They were then allowed to choose where their portion of the project would be mounted on the existing tree.

With everyone standing a safe distance away from the display, [Brett] pumped it full of propane and lit the various sections on fire. In the video below, you can see that the display was blown around a bit by the wind, but we imagine it would look pretty awesome on a still summer evening.

Even if you’re not into this sort of art, you have to admit that it certainly beats a boring old fire pit!

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[Dino] Tells Us About Transistor-based On/off Switches

August 22, 2011 by Mike Nathan 12 Comments

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You know them, you love them, you take them for granted – they are single push button on/off switches. As [Dino] explains in the most recent episode of his Hack a Week series, they are typically implemented in the form of IC logic switches nowadays, but it wasn’t always that way. When they first came on to the scene in the 70’s, the single button soft switches were built using a set of transistors and a capacitor to get the job done, so [Dino] decided to research push on/push off transistor switches a bit and build his own.

After reading through a short tutorial, he was ready to go. As he explains in the video, the operation of the switch is fairly simple, though he did run into some odd issues when he prototyped the switch on a piece of breadboard. He’s looking for someone to explain why the unstable circuit suddenly performs better with the addition of a small capacitor between the battery’s positive lead and the circuit’s output, so if you have some insight, be sure to speak up in the comments.

In the meantime, check out [Dino’s] exploration of push on/push off switches below.

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Polarized Art Fixture Made From A Busted Laptop Screen

August 22, 2011 by Mike Nathan 21 Comments

[Pedro] had a busted laptop LCD screen on his hands, but rather than throw it out, he brainstormed what he could possibly do with what would typically be considered a worthless item. He decided to make a simple art installation using the scrapped part, so he gathered a few other supplies and got to work.

The first thing he did was pull the LCD screen from the laptop, separating the front panel from the backlight panel. He drained the liquid crystal fluid from the display, and set it inside a picture frame in place of the glass. He added spacers around the edge of the frame so that the backlight could be mounted several inches behind the LCD panel.

[Pedro] then found a few polystyrene and polycarbonate plastic items from around the house, and placed them inside the frame. As you can see in the picture above, the polarizing filter built into the LCD screen makes for some pretty cool effects.

While you could debate for hours over exactly what is art, there’s no denying that his PolFrame looks cool and is a great way to save electronics from the scrap heap. We just want to know what he did with the LC fluid he drained from the screen!

Video: Shocking [Jack] Into Submission With High Voltage

August 22, 2011 by Jack Buffington 59 Comments

Hackaday headquarters has recently been overrun by techno-groupies hanging around outside so we decided to take some measures to discourage that. A word of warning though, if last week’s video ruffled your feathers then you probably shouldn’t watch this one. In this video [Jack] shows you how to create a stun glove using a disposable camera and some leather spikes. To prove that it really works, he intentionally takes a jolt from it courtesy of Hackaday’s security chief [Vlad].

Check out the video after the break.
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