       Serial.println(slit_position);
       updateLED();
     }
-    else if(command=="b") { // set brightness min value
+    // set brightness min value
+    // "b:[0.0-1.0];"
+    else if(command=="b") {
       // TODO argument check
       // argument is float
       brightness_min = argument.toFloat();

        Serial.println(argument);
      }
    }
    else if(command=="s") { // sound trigger
      brightness = 1.0;
    }
    else if(command=="d") { // set divide number
      
      if(argument.length()==1) {
        // argument is int

        Serial.println(argument);
      }
    }
    // set effect color
    // "e:[000-255].[000-255].[000-255];"
    else if(command=="e") {
      if(argument.length()==11) {
        e_color_r = constrainValue(argument.substring(0,3).toInt());
        e_color_g = constrainValue(argument.substring(4,7).toInt());
        e_color_b = constrainValue(argument.substring(8,11).toInt());
