I've never used bluetooth, but I've done a couple of sound-activated projects.
Which arduino would you recommend?
The Uno should be fine.
In fact, I don't know where to start really.
Take it one step at a time...
I'd start by wiring-up a couple of RGB LEDs and programming them to change color.
Then you can work on sensing audio. And, you need some way of sensing the start of your song sequence, so the timing doesn't drift-out after several runs. (I'm assuming the thing will loop over-and-over?) Probably just a longer pause between #8 & starting-over with #1 would do the trick.
You need to protect the Arduino's analog input from the audio signal's negative swing. You can bias the input to 2.5V (a capacitor and two equal-value resistors), or use a resistor and a couple of protection diodes
, or use a peak detector
. (In your applcation where you just need to sense the presense of an audio signal, I'd use the protection diode method.)
Last, I'd work on the bluetooth communication.