void setup() {
}

void loop() {
     int H , val ;
     int R , G , B ;

     val = analogRead(5) ;
     val = constrain(val, 80, 550) ;
     H   = map(val,80,550,0,360) ;

     if (H <= 120) {
          R = map(H,0,120,255,0) ;
          G = map(H,0,120,0,255) ;
          B = 0 ;
     } else if (H <= 240) {

          G = map(H,120,240,255,0) ;
          B = map(H,120,240,0,255) ;
          R = 0 ;
     } else {

          B = map(H,240,360,255,0) ;
          R = map(H,240,360,0,255) ;
          G= 0 ;
     }

     analogWrite(9,R) ;
     analogWrite(11,G) ;
     analogWrite(10,B) ;
}