const int ledPinRed = 11; // Red LED connected to analogue out pin
const int ledPinGrn = 10; // Green LED connected to analogue out pin
const int ledPinBlu = 9; // Blue LED connected to analogue out pin

// The Brightness potentiometer goes on an analogue pin, taking the pin from
// 0V to 5V.

const int potPinSat = 1;

// The Hue potentiometer goes on an analogue pin, taking the pin from
// 0V to 5V.

const int potPinHue = 2;

// The Beats potentiometer goes on an analogue pin, taking the pin from
// 0V to 5V.

const int potPinBeats = 3;

// Constants to define the ranges.

const int hueRedLow = 0;
const int hueRedHigh = 255;
const int hueBlue = 170;

// The size of the angle of one sector (1/6 of a colour wheel), and of a complete
// cycle of the colour wheel.

const int angleMin = 0;
const int angleSector = 60;
const int angleMax = 360;

const int brightMin = 0;
const int brightMax = 255;

//constants to define the range of beats
const int beatsMin = 40;
const int beatsMax = 220;

// Work variables.

// The hue potentiometer value is mapped to the range 0 to 360 (degrees).
int potValueHue;

//The brightness potentiometer value is mapped from 0 to 255 (full brightness)
int potValueSat;

//The beats potentiometer value is mapped from 40 to 220
int potValueBeats;

int hue, brightness;

const int saturation = 255;

// The brightess of each LED (0 to 255).

unsigned int r, g, b;

void setup() {
// Still need to set a baud rate, even for USB.
Serial.begin(9600);

// Set LED pins to output.
pinMode(ledPinRed, OUTPUT);
pinMode(ledPinGrn, OUTPUT);
pinMode(ledPinBlu, OUTPUT);

// Poteniometer analogue pin is an input.
pinMode(potPinHue, INPUT);
pinMode(potPinSat, INPUT);
pinMode(potPinBeats, INPUT);
}

void loop() {

// The Hue potentiometer value is mapped to degrees - 0 to 360 - for convenience.
potValueHue = map(analogRead(potPinHue), 0, 1023, angleMin, angleMax);
// The Brightness potentiometer value is mapped to values from 0 to 255.
potValueSat = map(analogRead(potPinSat), 0, 1023, brightMin, brightMax);
//The beats potentiometer value is mapped to values from 40 to 220 bpm
potValueBeats = map(analogRead(potPinBeats),0,1023, beatsMin,beatsMax);

// Colour wheel mode (red to red, wrapped around in a cycle).
hue = map(potValueHue, angleMin, angleMax, hueRedLow, hueRedHigh);
brightness = potValueSat;

// Do the conversion.
HSBToRGB(hue, saturation, brightness, &r, &g, &b);

analogWrite(ledPinRed, r);
analogWrite(ledPinGrn, g);
analogWrite(ledPinBlu, b);

// converting beats per minute to delay
int bpmToDelay = 1000 / (220/60);
delay(bpmToDelay);
}

// This function taken from here:
// http://eduardofv.com/read_post/179-Arduino-RGB-LED-HSV-Color-Wheel-

void HSBToRGB(
unsigned int inHue, unsigned int inSaturation, unsigned int inBrightness,
unsigned int *oR, unsigned int *oG, unsigned int *oB )
{
if (inSaturation == 0)
{
// achromatic (grey)
*oR = *oG = *oB = inBrightness;
}
else
{
unsigned int scaledHue = (inHue * 6);
unsigned int sector = scaledHue >> 8; // sector 0 to 5 around the color wheel
unsigned int offsetInSector = scaledHue - (sector << 8); // position within the sector unsigned int p = (inBrightness * ( 255 - inSaturation )) >> 8;
unsigned int q = (inBrightness * ( 255 - ((inSaturation * offsetInSector) >> 8) )) >> 8;
unsigned int t = (inBrightness * ( 255 - ((inSaturation * ( 255 - offsetInSector )) >> 8) )) >> 8;