const int rosso = 3;  // connessione led rgb
const int blu = 6;
const int verde = 5;
long potenzval;
int rossoval;
int verdeval;
int bluval;

void setup()
{
  pinMode(verde, OUTPUT);
  pinMode(rosso, OUTPUT);
  pinMode(blu, OUTPUT);
  randomSeed(analogRead(0));
}

void loop()
{
  potenzval = random(1023);

  if (potenzval > 511){
    verdeval = map (potenzval,0,510,0,255);
    analogWrite (verde, verdeval);
    analogWrite (blu, 255);
    rossoval = map (potenzval,0,510,255,0);
    analogWrite (rosso, rossoval);
  }
  if (potenzval <= 511){
    verdeval = map (potenzval,0,511,255,0);
    analogWrite (verde, verdeval);
    analogWrite (rosso, 255);
    bluval = map (potenzval,0,511,0,255);
    analogWrite (blu, bluval);
  }
  delay(500);
}