Old Chart Recorder Becomes Single-Pixel Scanner

July 8, 2017 by 7 Comments

With so many ways to capture images from paper, do we really need another one? Especially one that takes 15 minutes to capture a 128×128 pixel image? Probably not, but building a single-pixel RGB scanner is pretty instructive, and good clean fun to boot.

We have to admit that when [Kerry Wong] scored an ancient Hewlett-Packard X-Y chart recorder a while back, we wondered if it would lead to anything useful. One may quibble with the claim that the Lorenz attractor plotter he built with it is useful, and this single pixel scanner is equally suspect, but we like the idea. Using an Arduino to drive the X- and X-axis of the recorder through a raster pattern over the bed and replacing the pen with an RGB sensor board, [Kerry] was able to collect the color data for each pixel and reconstruct the image. It wouldn’t be too hard to replicate this if you don’t have an analog X-Y recorder, which just goes to show that not everything needs to be steppers and digital to get something useful done. Or at least semi-useful.

As for the RGB sensor used, they’ve made appearances here many times before, mostly in M&M sorters but with the occasional synesthesia simulator.

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Dropping Zip Bombs On Vulnerability Scanners

July 8, 2017 by 117 Comments

If you’ve ever looked at the server logs of a computer that lives full-time on the Internet, you know it’s a rough world out there. You’ll see hundreds of attempts per day to break in to your one random little box. Are you going to take that sitting down? Christian Haschek didn’t.

Instead of simply banning IPs or closing off services, [Christian] decided to hit ’em where it hurts: in the RAM. Now, whenever a bot hits his server looking for a poorly configured WordPress install, he serves them 10 GB of zeroes, compressed down into 10 MB by gzip:

dd if=/dev/zero bs=1M count=10240 | gzip > 10G.gzip

The classic trick uses zip multiple times on itself, which lets you compress arbitrarily large files into just a few kB. [Christian] tried this with gzip, and discovered that it didn’t automatically recurse, so he’s taking a small bandwidth hit for the team. If you know how to get more data packed smaller using gzip, leave a note in the comments.

Nobody really knows if this works on the bad guys’ servers, but [Christian] said that they stopped hitting him after downloading a couple payloads. If you want to test out what it does to your system, click this link. If you don’t run a server, but phishing e-mails get you hot under the collar, check out [Robbie Gallagher]’s talk on phishing the phishers from last year’s Schmoocon for cathartic tales of revenge.

Overhead Trolley Helps Clear The Air Over CNC Router

July 8, 2017 by 10 Comments

[Frank Howarth] has a shop most woodworkers would kill for, stuffed with enough tools to equip multiple hackspaces — four radial-arm saws alone! But while the CNC router in the middle of the shop, large enough to work on an entire sheet of plywood, is a gem of a machine, it was proving to be a dusty nightmare. [Frank]’s solution was as unique as his workspace — this swiveling overhead dust extraction system.

The two-part video below shows how he dealt with the dual problems of collection and removal. The former was a fairly simple brush-bristle shroud of the type we’ve featured before. The latter was a challenge in that the size of the router’s bed — currently 8′ but soon to be extended to 12′ — and the diameter of the hoses needed to move enough air made a fixed overhead feed impractical. [Frank]’s solution is an overhead trolley to support the hoses more or less vertically over the router while letting the duct swivel as the gantry moves around the work surface. There were a few pitfalls along the way, like hoses that shorten and stiffen when air flows through them, but in the end the system works great.

Chances are your shop is smaller than [Frank]’s, but you still need to control the dust. This dust collector for a more modest CNC router might help, as would this DIY cyclonic chip separator.

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Atari 2600 In A Game Cartridge

July 8, 2017 by 21 Comments

[PJ Evans] had a ruined game cartridge lying around, just waiting for a project. As Activision’s F-14 Tomcat game for the Atari 2600 console, it seemed ripe for use as a project enclosure of some sort. When he came across a couple of 9-pin D-sub joystick ports, he had an idea. He realized his Rasperry Pi Zero could fit inside the cartridge. Add a power button, TV color selector, difficulty switch, as well as select and reset buttons, and you have an emulator.

[PJ]’s Pi Zero had more than enough GPIO pins to accommodate all of those buttons and switches plus a bunch more for the joysticks. Why not put the emulator inside a game cartridge? In terms of software [PJ] looked into Adafruit’s Retro Gaming with Raspberry Pi resource, which has tons of suggestions for setting up game emulators. He decided on the RetroPie operating system to help him map out all of the pins, with Stella doing the actual Atari 2600 emulation.

Thanks, @seb_ly]!

Finally, A Calculator For The Atomic Age!

July 7, 2017 by 17 Comments

In the 1950s, a nuclear-powered future seemed a certainty. The public had not been made aware of the dangers posed by radioactive material, any large-scale accidents involving nuclear reactors had either been hushed up or were yet to happen, and industry and governments were anxious to provide good PR to further their aims. Our parents and grandparents were thus promised a future involving free energy from nuclear reactors in all sorts of everyday situations.

With the benefit of hindsight, we of course know how the story turned out. Windscale, Three Mile Island, Chernobyl, and Fukushima, and we’re still waiting for our atomic automobiles.

If you have a hankering for nuclear-powered domestic appliances though, all is not lost. [GH] is leading the charge towards a future of atomic energy, with a nuclear-powered calculator. It’s not quite what was promised in the ’50s, but it is nevertheless a genuine appliance for the Atomic Age. At its heart is not a 1950s-style fission reactor though, but a tritium tube. Beta particles from the tritium’s decay excite a phosphor coating on the tube’s inside wall, producing a small amount of light. This light is harvested with a solar cell, and the resulting electrical energy is stored in an electrolytic capacitor. The cell has an open-circuit voltage of 1.8 V, and the 100 μF capacitor in question stores a relatively tiny 162 μJ. From this source, a dollar store calculator can operate for about 30 sec, so there should be no hanging about with your mathematics.

We’ve brought you a tritium battery before, albeit a slightly larger one. And should you need the comforting glow of a tritium tube but not the radiation risk, how about this LED-based substitute?

Improved Game Tokens With Laser Cutting And Clever Design

July 7, 2017 by 6 Comments

[Martin Raynsford] is a prolific project maker, especially when it comes to using a laser cutter. These laser-cut token counters for the board game Tigris & Euphrates demonstrate some clever design, and show that some simple touches can make a big difference.

In the digital version of the game, the tokens conveniently display a number representing their total power value. [Martin] liked this feature, and set out to design a replacement token for the tabletop version that could display a number while still keeping the aesthetic of the originals. The tokens were designed as a dial with a small cutout window to show a number, but the surface of the token showing color and icon is still mostly unchanged.

Magnets hold the top and bottom together, and because of the small size of the assembly, no detents are needed. Friction is enough to keep things from moving unintentionally. The second noteworthy design feature is the material for the top layer of the token. This layer is made from 0.8 mm birch plywood; a nice and thin top layer means a wider viewing angle because the number is nearer to the surface. If the top layer were thicker, the number would be recessed and harder to see.

[Martin] made the design file available should anyone wish to try it out. No stranger to games, he even once game-ified the laser itself, turning it into a physical version of Space Invaders. Be sure to check it out!

 

Anyone Need A Little Fuming Nitric Acid?

July 7, 2017 by 67 Comments

If there’s a chemical with a cooler name than “fuming nitric acid,” we can’t think of it. Nearly pure nitric acid is useful stuff, especially if you’re in the business of making rocket fuels and explosives. But the low-end nitric acid commonly available tops out at about 68% pure, so if you want the good stuff, you’ll have to synthesize fuming nitric acid yourself. (And by “good stuff”, we mean be very careful with the resulting product.)

Fuming nitric acid comes in two colors – red fuming nitric acid (RFNA), which is about 90% pure and has some dissolved nitrogen oxides, giving it its reddish-brown color. White fuming nitric acid (WFNA) is the good stuff — more than 99% pure. Either one is rough stuff to work with — you don’t want to wear latex or nitrile gloves while using it. It’s not clear what [BarsMonster] needs the WFNA for, although he does mention etching some ICs. The synthesis is pretty straightforward, if a bit dangerous. An excess of sulfuric acid is added to potassium nitrate, and more or less pure nitric acid is distilled away from the resulting potassium sulfate. Careful temperature control is important, and [BarsMonster] seems to have gotten a good yield despite running out of ice.

We don’t feature too many straight chemistry hacks around here, but this one seemed gnarly enough to be interesting. We did have a Hackaday Prize entry a while back on improvements to the Haber process for producing ammonia, which curiously is the feedstock for commercial nitric acid production processes.

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