diff --git a/libctru/include/3ds/APT.h b/libctru/include/3ds/APT.h
index 5ce2fd6..3a42e9f 100644
--- a/libctru/include/3ds/APT.h
+++ b/libctru/include/3ds/APT.h
@@ -18,6 +18,21 @@ typedef enum{
 	APP_PREPARE_SLEEPMODE
 }APP_STATUS;
 
+enum {
+	APTSIGNAL_HOMEBUTTON   = 1,
+	// 2: sleep-mode related?
+	APTSIGNAL_PREPARESLEEP = 3,
+	// 4: triggered when ptm:s GetShellStatus() returns 5.
+	APTSIGNAL_ENTERSLEEP   = 5,
+	APTSIGNAL_WAKEUP       = 6,
+	APTSIGNAL_ENABLE       = 7,
+	APTSIGNAL_POWERBUTTON  = 8,
+	APTSIGNAL_UTILITY      = 9,
+	APTSIGNAL_SLEEPSYSTEM  = 10,
+	APTSIGNAL_ERROR        = 11
+};
+
+
 extern Handle aptEvents[3];
 
 Result aptInit(NS_APPID appID);
diff --git a/libctru/source/services/apt.c b/libctru/source/services/apt.c
index 36b0951..8af4915 100644
--- a/libctru/source/services/apt.c
+++ b/libctru/source/services/apt.c
@@ -196,8 +196,8 @@ void aptEventHandler(u32 arg)
 	
 					switch(signalType)
 					{
-						case 0x1: //home menu button got pressed
-						case 0x8: //power button got pressed
+						case APTSIGNAL_HOMEBUTTON:
+						case APTSIGNAL_POWERBUTTON:
 							if(aptGetStatus()==APP_RUNNING)
 							{
 								aptOpenSession();
@@ -211,7 +211,7 @@ void aptEventHandler(u32 arg)
 
 							break;
 
-						case 0x3: //preparing to enter sleep-mode
+						case APTSIGNAL_PREPARESLEEP:
 							aptStatus_beforesleepmode = aptGetStatus();
 							aptOpenSession();
 							APT_ReplySleepQuery(NULL, currentAppId, 0x1);
@@ -219,7 +219,7 @@ void aptEventHandler(u32 arg)
 							aptSetStatus(APP_PREPARE_SLEEPMODE);
 							break;
 
-						case 0x5: //entering sleep-mode
+						case APTSIGNAL_ENTERSLEEP:
 							if(aptGetStatus()==APP_PREPARE_SLEEPMODE)
 							{
 								aptOpenSession();
@@ -229,7 +229,7 @@ void aptEventHandler(u32 arg)
 							}
 							break;
 
-						case 0x6: //leaving sleep-mode
+						case APTSIGNAL_WAKEUP: // Leaving sleep-mode.
 							if(aptGetStatus()==APP_SLEEPMODE)
 							{
 								if(aptStatus_beforesleepmode == APP_RUNNING)GSPGPU_SetLcdForceBlack(NULL, 0);