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Powering LEDs? Answered

What I am trying to do is built a LED board that beats to music.  I have found many way to make it beat to the music, but my problem is I don't understand how to power the LEDs.  I am new to building electronics, and I am still learning.  Anyways, what my hope to do is use build a board 46in long running one LED per inch.  This will be dived up into smaller sections to run different beats off my home theater system.  I am trying to run all of this using  4 TIP31c, and I understand how to use them, I just am not sure how to power this.  Thank you!



6 years ago

Look up colour (color) organ and find a circuit suitable for what you want. Reinventing the wheel doesn't make sense here.

Do you want the bars to build up like a VU meter?
LM3915 vu meter

Do you want different frequency bands to affect different leds?
multiple LM3915 vu meterS, one per band

As you have in your picture, you've just added all the values together. You won't be running ALL the leds in series, nor will you be running ALL of them in parallel, so the numbers only add up in specific ways:
Series wiring: Add required voltage, current stays the same.
Parallel wiring: Voltage stays the same, current adds up.
Reality: You run off a fixed voltage power supply with a known maximum current, and base your other decisions around this- it means you're wiring some in series to add up to your available voltage, and make multiple series strands to add up to each channel/current you have available.


Answer 6 years ago

...or are you just asking how to make
which is visually identical to what you're asking...

...and is already written up...
...with instructions and video...


Answer 6 years ago

Basically yes, however mine has more LEDs. I also never saw how he powered his bar, nor how he made his beat to the music other than running a second set of speaker cable from the speaker.


Answer 6 years ago

Well what I meant is I am making that, not asking how to. The only problem is he doesn't show how to power it. Or how he made it beat to the music.


Answer 6 years ago

He's directly powering the leds from the speaker amplifier, a good way to burn out your amp.

They light up in sequence because there is increasing resistance on each led, so as the power (voltage) goes up, the leds light up further, with different channels for each colour.

I repeat my original question, if you want a VU meter, get VU meter drivers.

The SkinnerzTogroovy4u

Answer 6 years ago

It looks as though it is being driven directly from a proper speaker system, with the LEDs for each frequency range connected across the appropriate speaker. For running off of a normal mono/stereo system, you will need some external circuitry to detect each frequency.