Wrote this last year to demonstrate a potentiometer controlling an RGB LED.

Disclaimer: There are a thousand ways to do this better, with less code, but I "hacked" this into life.

paste this into your Arduino app and it will read better, I promise.

/* Pot as spectrum control

with new function Console for Serial monitoring

Hand coded by Terry Stainton*/

const int RED = 9;

const int GREEN = 10;

const int BLUE = 11;

const int SensorPin = 0;

int Red_Intensity=0;

int Green_Intensity=0;

int Blue_Intensity=0;

int PotVal=0;//Value of the potentiometer in 0-1023

int LoopCount=0;//used to control how often the console function is called

int Delay_ms=50;//50 best match for stability vs smooth glide

void setup () {

Serial.begin(9600);

pinMode(RED, OUTPUT);

pinMode(GREEN, OUTPUT);

pinMode(BLUE, OUTPUT);

}

void loop()

{

//if (LoopCount>50) {

//delay(Delay_ms);

//Console();//services the Seriol I/O Console at a controlled rate

 //}

//++LoopCount;

PotVal = analogRead(SensorPin); //Red

delay(10);

if (PotVal <= 340)    {//low end of the spectrum

Red_Intensity = (255-(PotVal*0.73));//starts at 255 full red. 0.73 scales the 340 sensor window to 255

analogWrite(RED, Red_Intensity); }

if (PotVal > 340) { //no Red in midrange of spectrum

Red_Intensity =0;

analogWrite(RED, Red_Intensity); }

if (PotVal >= 680){ //picks up Red again for indigo

Red_Intensity = ((PotVal-680)*0.73);

analogWrite(RED, Red_Intensity); }

  //Green (only indented for clarity. Above comments apply to green and blue

  delay(Delay_ms);

  if (PotVal <= 340)    {

  Green_Intensity = ((PotVal*0.73));

  analogWrite(GREEN, Green_Intensity); }

  if (PotVal > 340) { 

  Green_Intensity = ((255-(PotVal-340)*0.73));

  analogWrite(GREEN, Green_Intensity);

} if (PotVal >= 680){

  Green_Intensity =0;

  analogWrite(GREEN, Green_Intensity);

} //Blue

    delay(Delay_ms);

    if (PotVal >= 340)    

{ Blue_Intensity = (((PotVal-340)*0.73));

    analogWrite(BLUE, Blue_Intensity);

} if (PotVal > 680)

{ Blue_Intensity = ((255-(PotVal-680)*0.73));

    analogWrite(BLUE, Blue_Intensity);

} if (PotVal < 340)

{ Blue_Intensity =0;

    analogWrite(BLUE, Blue_Intensity);

} delay(Delay_ms);

}
//function Console for Serial Monitor void Console()

{

delay(10);

LoopCount=0; //resets the loop count

Serial.print("PotVal=");

Serial.println(PotVal);

Serial.print("Red_Intensity=");

Serial.println(Red_Intensity);

Serial.print("Green_Intensity=");

Serial.println(Green_Intensity);

Serial.print("Blue_Intensity=");

Serial.println(Blue_Intensity);

Serial.println("");

Serial.println("");

}