This is my first project with arduino. I wanted to do an analyzer for my PC. I liked the windows media player analyzers a lot, trying to watch patterns on the screen from the music and so on...
I searched a bit and I found the minim library for Processing. Thanks to that and the examples of FFT I was able to do it with not much effort (I thought it was gonna take me at least one month).
Here's a video with the result. Now I've seen blit video and other youtube videos of analyzers is not that great, but it's one of the few made playing with the brightness rather than the number of LEDs.
I think is a good project to try because all you need is your PC, 6 LEDs and resistors and you are settled 
.
Most of the time was spent trying to see which frequency bands to show and so on. Finally, I chose to do 240 mean linear bands, and afterwards to take the maximum of a certain range of them.
Here's the previous version with another song, it had some problems with syncronization (I added the bitwise operations later, and I had to change the brightness methode)
Here is the code if you want to try it. If you try it and change some values or something, please give feedback. I don't think I'll change much of the code, but the frequency bands are open to discussion.
Read the code carefully, there are some things you should change like serial ports, some recomendations and a lot of explanations.
Arduino code:
/*You'll need 6 LEDS to make it work, connected to the PWM pins on the arduino duemilanove.
If you have the arduino mega, you could put more LEDs, feel free to change the code.
I used a 100 ohm resistor, you can watch the LEDs I used (and a demo) on this video:
http://www.youtube.com/watch?v=pH9U5miKfcc
*/
const int vectledPin[]={3,5,6,9,10,11};
/*These are the values that will be given to the PWM ports on the arduino. The arduino will receive values between 0 and 30,
that measures the "volume" linearlly. However, the LED's don't bright linearlly, so I tested it a bit and put these values
as my own testing. I used the DIMMER sketch example on the arduino program to know what values to use.
Feel free to change them. One small change would be to make two vectors, as I used two different types of LEDs.*/
const int vectbright[]={0,1,2,3,4,6,8,19,14,18,22,27,32,38,47,56,66,76,86,96,105,114,122,130,138,148,162,190,222,255,255};
int i=0;
void setup()
{
// initialize the serial communication:
Serial.begin(9600);
// initialize the ledPin as an output:
for (i=0;i<6;i++)
pinMode(vectledPin[i], OUTPUT);
i=0;
}
void loop() {
byte brightness;
byte led;
// check if data has been sent from the computer:
if (Serial.available()) {
// read the most recent byte (which will be from 0 to 255):
brightness = Serial.read();
led=(brightness>>5);
//This reads what LED it is (it is stored on the 3 high bits)
brightness=((brightness)&0x1F);
//and this reads the 5 lower bits only. It puts a 0 in the higher ones.
analogWrite(vectledPin[led], vectbright[brightness]);
//and finally, using both vectors and the brightness index, the PWM value is sent
}
}
In the next post, Processing code (Needed more space for it)
