Another eerily similar high power LED driver hack

[Maximilian Güntner] dropped us a comment in last week’s globe writeup linking to his own project, which involves a similar high power LED driver mod. This looks like the exact same mod we came up with, and [Güntner] even used the mod to connect a bunch of high power LEDs to a PCA9685 LED driver [pdf]. It’s the same exact concept as Disco Planet!

It should come as no surprise that people have actually been modding high power led drivers in this way for some time. They are a few bucks per handful and take an enormous input voltage range. In [Güntner]‘s case he grabbed a bunch of these from Dealextreme.  Actually there are two others on the site, and all three contain comments (dating back a year) with helpful tips on various ways to modify the little PCB.

Our Ebay sourced boards are different though. The boards [Güntner] purchased employ the PowTech PT4115 [pdf] which uses fewer parts and has an easy to follow data sheet. Take, for instance, the pin graciously labeled “DIM” with a little PWM signal next to it. The nerve! The Ebay drivers use the MCP34063 [pdf] which has a much more cryptic data sheet (burned two weeks and several notebook pages to figure out the circuit). Ultimately the two are so similar it makes no difference.

So, if you want to mod some LED drivers on your own, check out the how-to video after the jump. Thanks [mguentner]!

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Adding Ambilight clone system to your home theater just got a big price cut

Whenever we get a tip claiming a project is cheap and easy we raise a cynical eyebrow. But [Yonsje] isn’t telling us a story, his Amiblight clone really does boil down the complexity and slash the price.

For the uninitiated, this is a clone of the Philips Amilight system that has been an option with some of their TVs over the years. It puts RGB LEDs on the back of the frame, pointed at the wall. They are tuned to the edge colors of the display, linking the color of the ambient light in the room to the colors on the screen. We’ve seen a ton of clones over the years, just search our blog for “Ambilight”.

Like the others, this iteration depends on you playing back video from a computer. [Yonsje] is using an Arduino with his own shield to connect to the HTPC. NPN transistors in the shield drive the RGB LEDs. The real cost savings is in his lighting source. A Deal Extreme RGB LED bar costs just $11.30 including shipping, and can be cut into six different segments for even spacing around your television. Check it out in the clip after the break.

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Bluetooth based Pseudorandom Number Generation

[MS3FGX] has done an interesting study about using Bluetooth adapters as a source for Pseudorandom Number Generation (PRNG). As it turns out, the Bluez package has a function that calls a remote Bluetooth adapter to return a random number. He picked up 10 compatible adapters for about $30 from DealExtreme and set about assembling some numbers to see how this compares to an OS-based PRNG.

Because millions of samples are needed for an accurate comparison, time became a problem. The adapters are a little bit slow responding to a request, sending just 4800 numbers in the first 30-second test. This can be overcome with multiple adapters being accessed by multiple computers for hours at a time. What can this be used for? Your guess is as good as ours, but [MS3FGX] has done a great job of writing up his tests. He’s also made a set of 20.7 million randomly generated values available if you want to generate your own statistical analysis.