That title is really misleading; this hack doesn’t require a lava lamp… anymore. I initially went googling for a 1996 project at SGI that generated random numbers by taking photos of a lava lamp. The lava lamp was chosen because of its chaotic nature. I was suprised to find that SGI had patented/trademarked the lavarand^tm technology. The system required you to use IRIX, took up a lot of space, and because of patents wasn’t easy to implement. In 2000 the engineers behind the original decided to develop an open source alternative know as LavaRnd (note the capital “L” and “R” ;-). [Editor’s note 2025: The domain has been taken over by an online casino.]

This iteration doesn’t use a lava lamp. Its source of chaos is camera with the lens cap on. The gain on the CMOS sensor is cranked all the way up to create a really noisy image. The image data is then sent through an algorithm to generate the random numbers. If you want to see the original project you’re going to have to ask the Wayback Machine.

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Here is a little something for your Memorial Day. My mouth began to water when this link first showed up. I clicked it and then

I’ve wondered about the crazy image URLs Amazon uses before, but not more than a few seconds. It seems a Peanuts fan decided to get to the bottom of it. Nat Gertler has deciphered the meanings  of most of the values that show up in Amazon URLs. It’s really simple to try out. Just pick out an image URL and start dropping in options: You can change the value and color of the percentage off bullet. Rotate the image to an arbitrary angle. Add “search inside” and “look inside” banners wherever you want. You can even view the original cover the book was submitted with.  Many of these options can be doubled up too. I can’t really think of what the “killer app” for this is, but it is fun to see the mechanisms behind web applications that have to serve thousands of people.

[via boingboing]

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Power over ethernet lets you add a DC voltage source to the unused pairs in your ethernet cable. This power can be used to power devices that are poe compatible by just plugging the cable into them. Other devices can be powered by using a “tap” to break the DC pairs back out of the cable. POE is a good choice for powering devices in remote locations. A router can be placed on a roof right next to its high-gain antenna, reducing signal loss, without having to run a separate AC line. Plugging the DC “injector” into a UPS will keep dedicated VOIP phones functioning during a power outage. Terry Schmidt has written a nice guide covering the theory behind scratch building poe injectors and taps. It also has photos and descriptions of other peoples projects along with tips on how to keep from turning your router into a pile of plastic goo.

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It is really hard to find good information online about proximity cards. I’m sure some companies consider this obscurity a form of security, but Jonathan Westhues demonstrates how severely flawed that notion is. He found a data sheet mentioning a 125kHz carrier frequency. He was off and running from there, eventually building a device that can read and repeat a proximity card’s data. It’s been argued that RFID technology is safe because of the short read distance. Jon actually found it easier to passively read cards that were being energized by a legitimate reader than by the device alone. Make sure you check out his home built PCB mill while you’re at the site.

[Thanks barbobot]

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quite awhile ago, the big thing to do was to impress your friends by rockin the debug menu on the coke machines around your mall. well, everyone forgot about pepsi

ahhh, yes. we knew one day that 400mhz would not be the fastest thing in the world on a pc. it’s gotten so out of control, that this juicer is a 433mhz beast of blending fury, well….two microcontrollers worth. It’s got wireless and it makes the absolute perfect juice combination. Using built in sensors and other fun stuff, it can measure the exact proportions for your custom made apple juice….everytime. It takes it’s commands via a keyboard or wireless remote and dispenses juices from above. My god, this world is getting better everyday. What’s next cornell? Wireless Egg beaters?

Continue reading “The Big Red Juicer” →