 void loop(){
   while(Serial.available() > 0) {
     int level = charToInt(Serial.read());
+    if(level < 0){
+      continue;
+    }
     setLevel(level);
   }
 

    previousMillis += INTERVAL;
    updateActualLevel();
    rainbow();
    Serial.println(mLevel);
  }
}


unsigned long currentMillis;

int charToInt(char c){
  int i = (int) c;
  if(i < 48 || 58 < i){
    return -1;
  }
  return (i - 48) * 6;
}

void decLevel(){
