diff --git a/flipcontrol_esp32/include/image.h b/flipcontrol_esp32/include/image.h
index 1bcdab0..e25d419 100644
--- a/flipcontrol_esp32/include/image.h
+++ b/flipcontrol_esp32/include/image.h
@@ -12,6 +12,13 @@
 
 #define UPDATE_INTERVAL 5 //TODO: remove this
 
+enum UpdateReturn {
+    wait,
+    finished,
+    nochange,
+    updating
+};
+
 class Image
 {
     
@@ -39,7 +46,7 @@ public:
     Image();
     void init();
 
-    bool updateByColumn(bool direction, bool clearFirst, bool optimizeClear, bool optimizeSet);
+    UpdateReturn updateByColumn(bool direction, bool clearFirst, bool optimizeClear, bool optimizeSet);
 
     uint8_t getW(); //returns Columns
     uint8_t getH(); //returns Rows
diff --git a/flipcontrol_esp32/src/image.cpp b/flipcontrol_esp32/src/image.cpp
index aad62aa..3767fd0 100644
--- a/flipcontrol_esp32/src/image.cpp
+++ b/flipcontrol_esp32/src/image.cpp
@@ -56,15 +56,15 @@ void Image::setBuffer_random(uint8_t randomness)
     
 }
 
-bool Image::updateByColumn(bool direction, bool clearFirst, bool optimizeClear, bool optimizeSet)
+UpdateReturn Image::updateByColumn(bool direction, bool clearFirst, bool optimizeClear, bool optimizeSet)
 {
 
     if (!flag_updating) {
-        return 1; //finished
+        return nochange; //finished
     }
 
     if (millis()-lastUpdateMillis<updateInterval){ //too early
-        return 0; //not finished
+        return wait; //not finished
     }
 
 
@@ -97,9 +97,9 @@ bool Image::updateByColumn(bool direction, bool clearFirst, bool optimizeClear,
     if (update_counter/2>=getW()) { //reached last column
         flag_updating=false;
         update_counter=0;
-        return 1; //finished
+        return finished; //finished
     }
-    return 0; //not finished
+    return updating; //not finished
 }
 
 
diff --git a/flipcontrol_esp32/src/main.cpp b/flipcontrol_esp32/src/main.cpp
index 39530bb..2bf3ea7 100644
--- a/flipcontrol_esp32/src/main.cpp
+++ b/flipcontrol_esp32/src/main.cpp
@@ -42,16 +42,14 @@ void loop() {
     }
 
 
-    static bool last_result;
-    bool result=flip.updateByColumn(0,0,0,0); //0=not finished, 1=finished
-    if (result && !last_result) //just finished
+    UpdateReturn result=flip.updateByColumn(0,0,0,0); //0=not finished, 1=finished
+    if (result == finished) //just finished
     {
         unsigned long duration=millis()-last_change;
         Serial.print("Last Change took "); Serial.print(duration); Serial.println(" ms");
         Serial.print("Update max took "); Serial.print(flip.updateDuration); Serial.println(" ms");
         flip.updateDuration=0; //reset
     }
-    last_result=result;
 
 
     /*