Hey guys, in this tutorial I will be showing you exactly how I set up my Arduino board to take a standard audio input and then flash a set of LEDs based on the frequency of the music playing.

Here's a short video of it in action:

YouTube

Step 1: Materials Needed

Here's a list of what materials you need and where to get them:

Note: I'm a big fan of Tayda Electronics, as their materials are very cheap and they usually post 15% off discounts on their Facebook Page.

1 x Breadboard
1 x 12V 5A power supply
note: this depends on how long you want your LED strip to be, I find that 5A is plenty for 5 meters, it could probably even handle more since you'll be fading between colors instead of having everything on maximum. Here's a look link to how I figured out the current draw: link
1 x LED strip (waterproof and nice 1M long strip here, super cheap and ok-quality 5M here)
1 x Audio Jack
3 x 10k resistors
1 x 220k resistor
1 x 33pf ceramic capacitor
2 x 100nf ceramic capacitor
1 x 10nf ceramic capacitor
1 x Arduino (I used a sparkfun-branded RedBoard, but an Arduino Uno would work fine
1 x 3.5mm audio cable
1 x MSGEQ7
3 x N-channel MOSFET Transistors
Many x male to male jumper cables

1 x speakers

Computer with Arduino Software Installed

Step 2: Setting Up the Circuit

Look at the attached picture for details. I used a combination of:

The RGB LED strip tutorial from Adafruit

The MSGEQ7 tutorial from skoba

I also attached my Fritzing file if you want to look at it.

EDIT: I made a small error in the Fritzing file. Please see the following comment (thank you Isaack19 for the clarification)

IMPORTANT: MAKE SURE PORT 2 (and any other ports that need to be grounded) ON YOUR MSGEQ7 IS NOT GROUNDED TO THE SAME GROUND AS YOUR MOSFETS. The Fritzing file shows the MSGEQ7 sharing ground with the MOSFET transistors. I was about to return my MSGEQ7 back from where I got it because of this. I almost gave up, but then I noticed in the serial monitor that when the 12v 5a power supply is plugged into the Arduino, the last two of seven frequencies spike up (it went from 0 0 0 0 0 4 19 to 0 0 0 0 0 8 39. Notice the last two numbers were also spiking up without the power supply plugged in.) Anyways, after grounding the MSGQE7 and the MOSFET transistors to separate grounds, all seven frequencies were at 0. I just wanted to share this with you because I saw some other people having problems.

Step 3: Setting Up the Script

I attached my script, let me know if you have any trouble with it. It's pretty straight-forward. Upload it to your Arduino and you should be good to go!

Here's also a pastebin of my code:

http://pastebin.com/wsHFADWe

msgeq7-led-code.ino
Download

Step 4: Final Steps

So what I ended up doing is getting a headphone splitter and then having one end go into an iPod/mp3 player, one end going to a set of speakers and then one end going into the audio jack on the arduino circuit. This way, the arduino circuit could get the audio input to change the lights, and the speaker could play the music at the same time. Hook everything up right, and you should be all set. Comment if you have any questions and/or suggestions!

Thanks for reading!