 int i_color_r = 255;
 int i_color_g = 0;
 int i_color_b = 0;
+float instrument_brightness_min = 0.5; // default brightness
+float instrument_brightness = 1;
 
 // effect color
 int e_color_r = 0;
 int e_color_g = 0;
 int e_color_b = 255;
-
-float instrument_brightness_min = 0.5; // default brightness
-float instrument_brightness = 1;
 float effect_brightness = 0;
+float effect_brightness_target = 0;
 
 int divide = 2; // LEDパターンの分割数
 float slit_position = 0.5; // 0~1 分割された区分の中のどこまでがinstrumentにするか。0だと全部effect color。1だと全部instrument color。

        Serial.println(argument);
      }
    }
    // sound trigger
    // "s:;"
    else if(command=="s") {

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