Updated Arduino Sketch to use proper State Machine

CaseLights.ino

  * The UV command turns the UV lights on or off (s can be 0 or 1).
  */
 
-//#define DEBUG
+#define DEBUG
+
+enum LoopState {
+  LOOP_IDLE,
+  LOOP_R,
+  LOOP_G,
+  LOOP_B,
+  LOOP_NUM1,
+  LOOP_NUM2,
+  LOOP_U,
+  LOOP_V
+};
 
 static int redPin = 10;
 static int greenPin = 9;
 static int bluePin = 11;
 static int uvPin = 13;
+static LoopState state = LOOP_IDLE;
+static int r = 0, g = 0, b = 0;
 
 void setup() {
   Serial.begin(115200);
+  Serial.setTimeout(5000);
   
   pinMode(redPin, OUTPUT);
   pinMode(greenPin, OUTPUT);
 
 void loop() {
   if (Serial.available() > 0) {
-    int c = Serial.read();
-    if (c == 'R') {
-      c = Serial.read();
-      if (c == 'G') {
-        c = Serial.read();
-        if (c == 'B') {
-          int r = Serial.parseInt();
-          int g = Serial.parseInt();
-          int b = Serial.parseInt();
-          analogWrite(redPin, r);
-          analogWrite(greenPin, g);
-          analogWrite(bluePin, b);
+    if (state == LOOP_IDLE) {
+      int c = Serial.read();
+      if ((c == 'R') || (c == 'r')) {
+        state = LOOP_R;
+      } else if ((c == 'U') || (c == 'u')) {
+        state = LOOP_U;
+      } else if ((c == '\r') || (c == '\n')) {
 #ifdef DEBUG
-          Serial.print("RGB set ");
-          Serial.print(r);
-          Serial.print(' ');
-          Serial.print(g);
-          Serial.print(' ');
-          Serial.print(b);
-          Serial.println();
+        Serial.println("Skipping newline...");
 #endif
-        } else {
+      } else {
 #ifdef DEBUG
-          Serial.print("Invalid character after G: ");
-          Serial.print(c);
-          Serial.println();
+        Serial.print("Invalid character: ");
+        Serial.print(c);
+        Serial.println();
 #endif
-        }
+      }
+    } else if (state == LOOP_R) {
+      int c = Serial.read();
+      if ((c == 'G') || (c == 'g')) {
+        state = LOOP_G;
       } else {
+        state = LOOP_IDLE;
 #ifdef DEBUG
         Serial.print("Invalid character after R: ");
         Serial.print(c);
         Serial.println();
 #endif
       }
-    } else if (c == 'U') {
-      c = Serial.read();
-      if (c == 'V') {
-        c = Serial.parseInt();
-        if (c == 0) {
-          digitalWrite(uvPin, LOW);
-#ifdef DEBUG
-          Serial.println("UV off");
-#endif
-        } else if (c == 1) {
-          digitalWrite(uvPin, HIGH);
+    } else if (state == LOOP_G) {
+      int c = Serial.read();
+      if ((c == 'B') || (c == 'b')) {
+        state = LOOP_B;
+      } else {
+        state = LOOP_IDLE;
 #ifdef DEBUG
-          Serial.println("UV on");
+        Serial.print("Invalid character after G: ");
+        Serial.print(c);
+        Serial.println();
 #endif
-        } else {
+      }
+    } else if (state == LOOP_B) {
+      r = Serial.parseInt();
+      state = LOOP_NUM1;
+    } else if (state == LOOP_NUM1) {
+      g = Serial.parseInt();
+      state = LOOP_NUM2;
+    } else if (state == LOOP_NUM2) {
+      b = Serial.parseInt();
+      analogWrite(redPin, r);
+      analogWrite(greenPin, g);
+      analogWrite(bluePin, b);
 #ifdef DEBUG
-          Serial.print("Invalid character for UV: ");
-          Serial.print(c);
-          Serial.println();
+      Serial.print("RGB set ");
+      Serial.print(r);
+      Serial.print(' ');
+      Serial.print(g);
+      Serial.print(' ');
+      Serial.print(b);
+      Serial.println();
 #endif
-        }
+      state = LOOP_IDLE;
+    } else if (state == LOOP_U) {
+      int c = Serial.read();
+      if ((c == 'V') || (c == 'v')) {
+        state = LOOP_V;
       } else {
+        state = LOOP_IDLE;
 #ifdef DEBUG
         Serial.print("Invalid character after U: ");
         Serial.print(c);
         Serial.println();
 #endif
       }
-    } else if ((c == '\n') || (c == '\r')) {
+    } else if (state == LOOP_V) {
+      int n = Serial.parseInt();
+      if (n == 0) {
+        digitalWrite(uvPin, LOW);
 #ifdef DEBUG
-      Serial.println("Skipping new-line or carriage-return...");
+        Serial.println("UV off");
 #endif
+      } else {
+        digitalWrite(uvPin, HIGH);
+#ifdef DEBUG
+        Serial.println("UV on");
+#endif
+      }
+      state = LOOP_IDLE;
     } else {
+      state = LOOP_IDLE;
 #ifdef DEBUG
-      Serial.print("Invalid character: ");
-      Serial.print(c);
+      Serial.print("Invalid state: ");
+      Serial.print(state);
       Serial.println();
 #endif
     }

CaseLights/Info.plist

 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
-	<string>117</string>
+	<string>118</string>
 	<key>LSApplicationCategoryType</key>
 	<string>public.app-category.utilities</string>
 	<key>LSMinimumSystemVersion</key>

CaseLights/Serial.m

         // incoming calls, for example, a fax listener.
         
         deviceFilePathAsCFString = IORegistryEntryCreateCFProperty(modemService,
-                                                                   CFSTR(kIODialinDeviceKey),
+                                                                   CFSTR(kIOCalloutDeviceKey),
                                                                    kCFAllocatorDefault,
                                                                    0);
         if (deviceFilePathAsCFString) {