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LED driven from speaker on motherboard

TechEureka

Jul 9, 2010
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TechEureka is building a new type of networking system where the motherboard is attached to a sheet of 12 x 18" plexiglass, sitting on a wire shelf. Part of the goal is to remove the 200 pounds of rack and 30 pounds each of server case for a server that is sitting in an air conditioned server farm in a locked wire cage.

Now that you have the picture, I would like to place single color LED to attach to the two wire speaker output on the motherboard, and then drill a hole in the plexiglass for it. As the speaker sounds off, it flashes the entire plexiglass for a kind of light show. Would prefer a multi-colored LED driven by the a tone on the speaker, but if it requires additional circuits, just the single color.

Running the LED off the speaker allows me to put on a light show for a camera, rather than the random LED of accessing the hard drive, etc. Planning on hundreds of motherboards...

Can anyone help?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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One of the main things that 1U cases do is to direct air efficiently to where cooling is required since there is little room for individual fans on heatsinks. Without a case (and presumably with similar (or higher) density than 1U cases, how do you intend to do this?

The simple solution is to regard the speaker output as a 0 to 5V signal and place a suitable resistor in series to limit the current to 20 mA. the issue is far more complex if you want to encode colours as tones. If you wante to do that, it may be simpler to interface to USB or a parallel port, or even use the signals for the keyboard lights)
 
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trobbins

Jun 15, 2010
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You may need to rectify and filter the speaker signal to get a more sustained signal through the LED to assist normal eye response - but that sort of depends on the signal you will be outputing to the LED. Were you going to do a custom generated repetitive signal?

Ciao, Tim
 

TechEureka

Jul 9, 2010
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Just want to create a sound or buzz on the internal motherboard speaker, and it will excite an LED. Using multiple motherboards, arranged in an array, sitting on plexiglass, I can create a geek light show.

By the way, this project is to provide 1.5 million hosted free personally branded websites to help people find a job. Anticipate hundreds of web servers in the project. So using coordinated motherboard beeps, it should be a good light show.
 

trobbins

Jun 15, 2010
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Have you done a simple test yet? If your not sure then I suggest you replace your speaker with a led in series with a 10 ohm resistor, and add another led in parallel with the first led - but put it in the other direction. Try some sound clips and check the visuals.

Tim
 
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