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

        Serial.println(argument);
      }
    }
    else if(command=="p") { // set position
      // TODO argument check
      // argument is float
      slit_position = argument.toFloat();

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