Weekly Roundup 1/21/12

In case you were asleep at the wheel, here are our top stories of the week.

Our most popular post was one that shows you how to make your own ‘personal assistant’ using Wolfram Alpha, text to speech software, and the phone network. It still won’t get your coffee though. You’ll just have to do that yourself.

Coming in at second place was a post about how to use your Android camera phone as a Geiger counter. Of course, this hack will work with any device that uses a CMOS sensor to do its imaging but they have gone and wrapped it up into a nice app.

Do you have access to a laser cutter and a burning desire (pun intended) to make gears? In this post Alex makes some acrylic gears using an Epilog laser cutter.

When is our government going to get it through their heads that we don’t want the internet to be controlled by a small group of corporations? Probably when the lobbyists stop giving them money by the boat load to do just that… It seems like several times a year a bill comes through that would severely restrict the internet or would at least allow someone to shut down a website without any sort of due process. Luckily, groups like the EFF are paying attention and are well organized for getting the word out there. This post was our stand against the current bills that threaten our internet freedom.

Finally, on a lighter note, we have a post about how to do ultrasonic welding on the cheap using a ‘heat staker’ and a small drill press.

PVC Magnetometer to measure magnetic storms

In the hopes of getting a heads up on when the aurora borealis will be visible from his back yard, [Alex] built a magnetometer to measure disruptions in Earth’s magnetic field. The build is extremely simple, too. It’s amazing what you can build with a few components and a trip to the dollar store.

The design or [Alex]‘s project is called a torsion magnetometers. In this setup, two mirrors are affixed to a permanent magnet connected to a string. A laser is shone onto the mirror and is reflected back to an array of sensors. In [Alex]‘s case he used a simple laser pointer and a pair of photoresistors encased in a PVC tube.

[Alex] has been running his magnetometer in his back yard for over a month now and has the data to prove it. Luckily for [Alex], those graphs he has been generating may get a little more interesting. A coronal mass ejection is coming our way and is expected to hit today around 22:30 UTC. We’ll go outside to look for an aurora, but we’re sure [Alex] will be glued to his laptop tonight.

Check out the CGI visualization of [Alex]‘s magnetometer after the break

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Overlaying video on encrypted HDMI connections

[bunnie] is up to his old tricks again. He successfully implemented a man-in-the-middle attack on HDCP-secured connections to overlay video in any HDMI video stream. There’s a bonus, too: his hack doesn’t use the HDCP master-key. It doesn’t violate the DMCA at all.

HDCP is the awful encryption scheme that goes into HDMI-compatable devices. Before HDCP, injecting video overlays or even chroma keying was a valid interpretation of fair use. [bunnie] thinks that HDMI devices should have the same restrictions analog devices have, so he decided to funnel his own video into his TV.

The build uses the NeTV, a handy and cheap FPGA board with an HDMI input and output. [bunnie] got the FPGA to snoop the HDMI bus and decide if a pixel needs to be changed or not. This isn’t much different from what researchers in Germany did a few months ago, but unlike the academic security researchers, [bunnie] gives you a shopping list of what to buy.

As an example of his work, [bunnie] implemented something like a ‘tweet ticker’ on HDCP-encrypted video. There’s very little the NeTV setup can’t do from chroma keying, filters, or simply dumping the HDMI stream to a hard disk. Check out the slides from [bunnie]‘s talk to get better idea of what he did.

[PAPPP] found a video of the talk in question. Check that out after the break.

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FLORA: a better Arduino LilyPad

[Ladyada] has been working on FLORA, her wearable electronics platform, for a few months now. Even though it has just been announced the specs look much better than the previous queen of the hill, the Arduino LilyPad.

Going down the spec sheet for both the FLORA and the LilyPad, we see that FLORA has twice as much flash and SRAM as the LilyPad. The LilyPad has more options for I/O, but [Ladyada]‘s FLORA has the benefit of not using an ISP header for programming; FLORA is completely USB-compatable. FLORA is also about a quarter-inch in diameter smaller than the LilyPad, something to take into account when you’re going for a wearable project.

On top of Bluetooth, GPS, accelerometer, compass and other modules planned for FLORA ( it doesn’t look like they’re available yet, though), FLORA has USB HID support so it can operate as a USB keyboard, mouse, MIDI device, or connect to a cell phone. If you’ve ever wanted a keytar cardigan, this is the board for you.

Check out [Ladyada]‘s video demo of a LED-equipped fabric after the break.

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Trashed Hard Drive? Why not an Engraved Clock?

So your hard drive quit working.  Don’t despair, with a “little” work your disk can be repurposed into a clock like the one seen above. I made this clock after several iterations of various success, including the first revision, which was simply the platter with a clock kit from a hobby store screwed into the middle. Still a very neat effect, but if you want to actually tell what time it is, it helps to have the numbers available.

For this, you’ll need some sort of CNC machine (a kit-build router in this case), and some way to generate the Gcode to get everything cut correctly. A guide to how the logo was eventually turned into something a machine could understand is provided here. Of course if you’re not sure what logo would look good on your clock, you can always skip a few steps and engrave the our logo. In this [HAD] article, it’s conveniently provided in .dxf format, which can be converted by a CAM (computer-aided manufacturing) program into code that your machine can understand.

Check out after the break for a video of two “platter clocks” being engraved using these methods: [Read more...]