diff --git a/flipcontrol_esp32/include/image.h b/flipcontrol_esp32/include/image.h
index 8c1ac66..1bcdab0 100644
--- a/flipcontrol_esp32/include/image.h
+++ b/flipcontrol_esp32/include/image.h
@@ -32,6 +32,7 @@ private:
 
     unsigned long updateInterval;
 
+    
 
 
 public:
@@ -44,9 +45,12 @@ public:
     uint8_t getH(); //returns Rows
 
     void setBuffer_solid(bool set);
+    void setBuffer_random(uint8_t randomness);
 
     void loop_testDots();
     void loop_drawClearTest();
+
+    unsigned long updateDuration; //for statistics and debugging. time it took for one update (max)
 };
 
 #endif
diff --git a/flipcontrol_esp32/src/image.cpp b/flipcontrol_esp32/src/image.cpp
index d797259..fbbf2e7 100644
--- a/flipcontrol_esp32/src/image.cpp
+++ b/flipcontrol_esp32/src/image.cpp
@@ -14,7 +14,7 @@ void Image::init()
 
     flag_updating=false;
     update_counter=0;
-    updateInterval=50;
+    updateInterval=30;
 }
 
 uint8_t Image::getW() {
@@ -39,16 +39,35 @@ void Image::setBuffer_solid(bool set)
     
 }
 
+void Image::setBuffer_random(uint8_t randomness)
+{
+    for (uint8_t x=0;x<getW();x++) {
+        uint16_t randomnumber=0;
+        for (uint8_t y=0;y<getH();y++) {
+            if (random(256)<randomness) { //the higher the parameter the more white
+                randomnumber+=pow(2, y);
+            }            
+        }
+        backBuffer[x]=randomnumber;
+        //backBuffer[x]=(uint16_t)random(0x10000);     
+    }
+
+    flag_updating=true; //make update run
+    
+}
+
 bool Image::updateByColumn(bool direction, bool clearFirst, bool optimizeClear, bool optimizeSet)
 {
-    if (millis()-lastUpdateMillis<updateInterval){ //too early
-        return 0; //not finished
-    }
 
     if (!flag_updating) {
         return 1; //finished
     }
 
+    if (millis()-lastUpdateMillis<updateInterval){ //too early
+        return 0; //not finished
+    }
+
+
     lastUpdateMillis=millis();
 
     uint8_t x=update_counter/2;
@@ -73,6 +92,10 @@ bool Image::updateByColumn(bool direction, bool clearFirst, bool optimizeClear,
 
     update_counter++; //next column
 
+    unsigned long _duration=millis()-lastUpdateMillis; //how long it took to shift data and flip dots in this update
+    updateDuration=max(updateDuration,_duration); //store maximum value
+    
+
     if (update_counter/2>=getW()) { //reached last column
         flag_updating=false;
         update_counter=0;
diff --git a/flipcontrol_esp32/src/main.cpp b/flipcontrol_esp32/src/main.cpp
index f9c7666..39530bb 100644
--- a/flipcontrol_esp32/src/main.cpp
+++ b/flipcontrol_esp32/src/main.cpp
@@ -27,16 +27,34 @@ void loop() {
     
     static unsigned long last_change=0;
     static bool color=0;
-    if (loopmillis-last_change >= 10000) 
+    if (loopmillis-last_change >= 5000) 
     {
-        Serial.print("Change to Solid color ="); Serial.println(color);
-        flip.setBuffer_solid(color);
-        color=1-color;
+        //Serial.print("Change to Solid color ="); Serial.println(color);
+        //flip.setBuffer_solid(color);
+        //color=1-color;
+
+        uint8_t _randomvalue=random(256);
+        Serial.print("set buffer random. ");
+        Serial.println(_randomvalue);
+        flip.setBuffer_random(_randomvalue);
 
         last_change=loopmillis;
     }
 
 
+    static bool last_result;
+    bool result=flip.updateByColumn(0,0,0,0); //0=not finished, 1=finished
+    if (result && !last_result) //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;
+
+
+    /*
     if (loopmillis > last_update + UPDATE_INTERVAL) 
     {
         Serial.print("UpdateByColumn ");
@@ -45,6 +63,7 @@ void loop() {
 
         last_update=loopmillis;
     }
+    */
     
 
     /*