I saw a YouTube Video of someone who used an aux cord input into pin A0 on their Arduino to control a strip of LEDs. I have a strip of Adafruit's RGB NeoPixel LEDs, but I'm not sure how to input my audio into pin A0. If there is a way to do this without a separate shield or board, that'd be great because I'm on a tight budget, but if not possible it'll have to do. Also, would it be possible to send this audio to another Arduino via wifi or bluetooth using a different shield? Thanks.

1 Answer 1


Depending on how loud your audio signal is, you may be able to do it with just one capacitor and two resistors:

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If your signal is quite quiet, though, you may need to amplify it using an op-amp. For instance:

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That arrangement would double the volume of the audio. It also has the effect of inverting it, so you will need to invert your readings in software.

Also note that both of these methods will give you an AC waveform centred around 2.5V, so silence will be a reading of around 512, and it will go up and down from there. You can sample that audio waveform and do some basic (though quite slow on an Arduino) analysis of it, such as FFT to get the frequency content of the audio - great for visual effects...

  • Okay. I have these cheapy water speakers. You're suppose to plug the second speaker into the main one via mini usb, but I figured out that if you actually plug the Arduino into it, it has a constant green status led and the RX and TX LEDs glow to the beat of the music. Would it be possible to feed this to the code that was provided in the description of the video I linked in my main post above? I'm not quite sure how to analyze the connection. Since I'm kinda newly, I figured this he'd easier than the method you listed above.
    – jeffresc
    Jun 22, 2016 at 4:32

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