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Wisconsin
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Hello!
http://hacknmod.com/hack/led-light-box-thumps-to-your-music/
I'm trying to make that!
But i have issues
1)I want to use a socket instead of a plug
2)I don't have a 12v battery, I want to run it at 5v
3) I want to run a lot of leds, so i need to wire it up in parallel

GO NOW ARDUINO FORUMS! DO MY BIDDING!! MUAHAHAHA!
no but really, I've been trying to work on this alllllll day, which means over 10 hours! I NEED HELP!!
Please help smiley
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Fort Lauderdale, FL
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1)I want to use a socket instead of a plug
Okay, that should be an easy change.

2)I don't have a 12v battery, I want to run it at 5v
Looks like the circuit relies on the LEDs to have a 3V forward voltage.  There really should still be a current limiting resistor in the design.  Since the LEDs are not addressed individually, you could use a 5V supply and put them in parallel instead of series.
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Okay, I'll try that again.  I think my tip31 is burnt out or some crap like that
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Okay, I'll try that again.  I think my tip31 is burnt out or some crap like that

That could happen if you used LEDs without a current limiting resistor... smiley-wink
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well the diagram doesn't say to use a resistor
what value would i even use?
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well the diagram doesn't say to use a resistor
Not everything on the internet is correct.

That circuit relies on the power supply to act as a constant current supply, which isn't a good idea.  When a LED has its forward voltage dropped across itself, it effectively turns into a short circuit.  This is why you use a current limiting resistor.  The voltage drop of the LED is constant.  This means the voltage dropped across the resistor is constant and there is a linear relationship of voltage and resistance with a resistor.  This will create a constant current through the resistor.  Since the resistor is in series with the LED, it limits the amount of current the LED draws.

what value would i even use?
Depends on the maximum current allowed by the LED, how bright you want it, and how much current is available by your supply.
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Schematic posted on hacknmod is good example how NOT to do.
Use this one instead:
http://arduino.cc/playground/uploads/Learning/multiple_leds2.jpg
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How would that one be changed so that you could use it for the audio input?
all of them are arduino....
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Connect to audio output , line level and up. Speakers (< 2 W) and headphones outputs should be o'k too.
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Ah the only thing i want this meter to do with the arduino is the ground and +5,
I want to still use the tip31, its just using it properly. I know how to change the wiring so its parallel but i dont understand why it won't work.

...in my first diagram, it says left OR right, can i just put both on that pin?
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The original diagram was meant to be connected to an audio source, 12 volt battery, and 4 LEDs.

You're using "lots of LEDS", a 5V supply, and an Arduino as the source.  At what point are you going to realize this circuit has nothing to do with what you are trying to do?
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Yes, you can put both. Type of transistor doesn't matter much, as long as its V-I spec.  not exceeded.
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Quote
The original diagram was meant to be connected to an audio source, 12 volt battery, and 4 LEDs.

You're using "lots of LEDS", a 5V supply, and an Arduino as the source.  At what point are you going to realize this circuit has nothing to do with what you are trying to do?

I think you a little butt-hurt because you don't understand what i'm trying to convey, probably my fault.  Thank you for your help thus far.

Quote
Yes, you can put both. Type of transistor doesn't matter much, as long as its V-I spec.  not exceeded.

Alright then, I think i'm just going to do a all-or-nothing run.  Coming off of the breadboard and off to the soldering iron.  wish me luck!
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