       updateLED();
     }
   }
+}
+
+bool equal(String str1, String str2) {
+  return str1.compareTo(str2)==0;
 }
 
 // limitation of brightness

      Serial.println(slit_position);
      updateLED();
    }
    else if(command=="b") { // set brightness min value
      // TODO argument check
      // argument is float
      brightness_min = argument.toFloat();

        Serial.println(argument);
      }
    }
    else if(equal(command,"effect")) { // set effect color
      if(argument.length()==11) {
        // argument likes "255.255.255"
        e_color_r = constrainValue(argument.substring(0,3).toInt());
