Here is a video of my Color Organ set up in my living room.
I am using the 6 PWM outputs of the Arduino to drive a SparkFun Power MosFet shield, which then drives 6 LED strips proportional to the audio level in each of the 6 audio regions. The audio is picked up with a SparkFun Electret Microphone
and then fed into the Spectrum shield. The MSGEQ7 IC on the shield does the audio sampling which is then fed into the Arduino.
I found some LED strips that are 16 ft. long so I bought 6 of them. Each LED strip draws approximately 2 amps each, so directly using the Arduino 6 PWM outputs was out of the question, I decided to use the SparkFun MosFet power driver shield to drive the LED strips.
Additionally, my power supply needs to handle at least 12 amps a 12 volts. For this, I used an old ATX computer power supply I had laying around. However you can’t just use a computer power supply straight away, you have to do a bit of hacking of it to get it to work outside of a computer. Not to worry, here are some directions for hacking a computer power supply.
One thing about the SparkFun Spectrum shield that I wish had been done differently is that they used one of the Arduino’s PWM outputs to reset the MSGEQ7 IC. This seems like a waste of a PWM output to me as they could have just as easily used a non-PWM output, such as Digital Out #7. Since I was going to use the MosFet Power Driver, which has 6 channels, I decided to modify the Spectrum Shield to use output D7. Its not a huge deal, I just cut the trace to the MSGEQ7 and jumpered it over to the D7 output. Doing this modification now gives me 6 PWM outputs instead of 5 for the LED strips.
Here is a photo of the modified Spectrum shield:
Sparkfun Spectrum Board Mod for Mike’s Color Organ