diff --git a/src/BASICS.h b/src/BASICS.h
index 7e66f39..e71cef4 100644
--- a/src/BASICS.h
+++ b/src/BASICS.h
@@ -6,6 +6,24 @@
 #define X true
 #define _ false
 
-typedef unsigned long millis_t;
+typedef int64_t microseconds_t;
+
+double step(double valueCurrent, double valueMin, double valueMax, microseconds_t timeTotal, microseconds_t timeDelta) {
+  double valueRange = valueMax - valueMin;
+  double timeRatio = (double) timeDelta / (double) timeTotal;
+  double valueStep = valueRange * timeRatio;
+  double valueNew = max(valueMin, min(valueMax, valueCurrent + valueStep));
+//  Serial.printf("valueCurrent:   %13.3f\n", valueCurrent);
+//  Serial.printf("valueMin:       %13.3f\n", valueMin);
+//  Serial.printf("valueMax:       %13.3f\n", valueMax);
+//  Serial.printf("valueRange:     %13.3f\n", valueRange);
+//  Serial.printf("timeTotal:      %13.3f\n", (double) timeTotal);
+//  Serial.printf("timeDelta:      %13.3f\n", (double) timeDelta);
+//  Serial.printf("timeRatio:      %13.3f\n", timeRatio);
+//  Serial.printf("valueStep:      %13.3f\n", valueStep);
+//  Serial.printf("valueNew:       %13.3f\n", valueNew);
+//  Serial.println();
+  return valueNew;
+}
 
 #endif
diff --git a/src/main.cpp b/src/main.cpp
index 9329dbe..253bc9a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,4 +1,5 @@
 #include <WiFi.h>
+#include <ArduinoOTA.h>
 #include "mode/Mode.h"
 #include "mode/GameOfLife/GameOfLife.h"
 #include "display/Display.h"
@@ -12,7 +13,7 @@ enum ModeId {
     BORDER,
     CLOCK,
     GAME_OF_LIFE_BLACK_WHITE,
-    GAME_OF_LIFE_WHITE_FADE,
+    GAME_OF_LIFE_GRAYSCALE,
     GAME_OF_LIFE_COLOR_FADE,
     GAME_OF_LIFE_RANDOM_COLOR,
     PONG,
@@ -21,11 +22,11 @@ enum ModeId {
 
 Display display(32, 8);
 
-ModeId newModeId = SPACE_INVADERS;
+ModeId newModeId = GAME_OF_LIFE_GRAYSCALE;
 
 ModeId currentModeId = NONE;
 
-millis_t lastMillis = 0;
+microseconds_t lastMicros = 0;
 
 Mode *mode = nullptr;
 
@@ -48,17 +49,19 @@ void setup() {
   Serial.begin(115200);
   Serial.println("\n\n\nStartup!");
   WiFi.begin("HappyNet", "1Grausame!Sackratte7");
+  ArduinoOTA.begin();
   display.setup();
 }
 
 void setSpeed(double value);
 
 void loop() {
+  ArduinoOTA.handle();
   bool hasIp = (uint32_t) WiFi.localIP() != 0;
   if (!connected) {
     if (hasIp) {
       connected = true;
-      Serial.println("WiFi connected!");
+      Serial.printf("WiFi connected: %s\n", WiFi.localIP().toString().c_str());
       configTime(3600, 3600, WiFi.gatewayIP().toString().c_str());
     }
   } else {
@@ -108,7 +111,7 @@ void setBrightness(int value) {
 }
 
 void setSpeed(double value) {
-  speed = min(1000.0, max(0.001, value));
+  speed = value;
   Serial.printf("Setting speed to %6.2fx\n", value);
 }
 
@@ -129,7 +132,7 @@ void unloadOldMode() {
 
 void loadNewMode() {
   currentModeId = newModeId;
-  lastMillis = 0;
+  lastMicros = 0;
   switch (currentModeId) {
     case NONE:
       break;
@@ -142,7 +145,7 @@ void loadNewMode() {
     case GAME_OF_LIFE_BLACK_WHITE:
       mode = new GameOfLife(&display, BLACK_WHITE);
       break;
-    case GAME_OF_LIFE_WHITE_FADE:
+    case GAME_OF_LIFE_GRAYSCALE:
       mode = new GameOfLife(&display, GRAYSCALE);
       break;
     case GAME_OF_LIFE_COLOR_FADE:
@@ -165,8 +168,8 @@ void stepMode() {
   if (mode == nullptr) {
     return;
   }
-  millis_t currentMillis = millis();
-  millis_t dt = currentMillis - lastMillis;
-  lastMillis = currentMillis;
-  mode->step((millis_t) max(1.0, (double) dt * speed));
+  auto currentMicros = (int64_t) micros();
+  microseconds_t dt = (microseconds_t) min(1000000.0, max(1.0, (double) (currentMicros - lastMicros) * speed));
+  lastMicros = currentMicros;
+  mode->step(dt);
 }
diff --git a/src/mode/Clock/Clock.h b/src/mode/Clock/Clock.h
index e9cd4d4..18d66b9 100644
--- a/src/mode/Clock/Clock.h
+++ b/src/mode/Clock/Clock.h
@@ -100,7 +100,7 @@ public:
       return "Clock";
     }
 
-    void step(millis_t dt) override {
+    void step(microseconds_t dt) override {
       tm time{};
       getLocalTime(&time);
       display->clear();
diff --git a/src/mode/GameOfLife/Cell.h b/src/mode/GameOfLife/Cell.h
index cee8f6a..3b33d5a 100644
--- a/src/mode/GameOfLife/Cell.h
+++ b/src/mode/GameOfLife/Cell.h
@@ -13,12 +13,18 @@ public:
 
     uint32_t color = 0;
 
-    void animate(double per255Points) {
+    void animate(microseconds_t dt) {
+      // TODO "step" does not work as expected
       if (alive) {
-        fade = min(255.0, fade + per255Points);
+        fade = step(fade, 0.0, 255.0, 200000, +dt);
       } else {
-        fade = max(0.0, fade - per255Points);
+        fade = step(fade, 0.0, 255.0, 200000, -dt);
       }
+//      if (alive) {
+//        fade = min(255.0, fade + (double) dt / 200000.0);
+//      } else {
+//        fade = max(0.0, fade - (double) dt / 200000.0);
+//      }
     }
 
     uint8_t getR() const {
diff --git a/src/mode/GameOfLife/GameOfLife.h b/src/mode/GameOfLife/GameOfLife.h
index 59e5f54..1e4eb53 100644
--- a/src/mode/GameOfLife/GameOfLife.h
+++ b/src/mode/GameOfLife/GameOfLife.h
@@ -15,7 +15,7 @@ private:
 
     ColorMode colorMode;
 
-    millis_t runtime = 0;
+    microseconds_t runtime = 0;
 
     uint8_t steps = 0;
 
@@ -69,9 +69,9 @@ public:
       return "???";
     }
 
-    void step(millis_t dt) override {
+    void step(microseconds_t dt) override {
       runtime += dt;
-      if (runtime >= 500) {
+      if (runtime >= 500000) {
         runtime = 0;
         if (lastAliveCount == aliveCount) {
           isSteadyCount++;
@@ -150,7 +150,7 @@ private:
       }
     }
 
-    void animate(millis_t dt) {
+    void animate(microseconds_t dt) {
       Cell *cell = cells;
       for (int y = 0; y < display->height; y++) {
         for (int x = 0; x < display->width; x++) {
diff --git a/src/mode/Mode.h b/src/mode/Mode.h
index be9c1a3..7830062 100644
--- a/src/mode/Mode.h
+++ b/src/mode/Mode.h
@@ -10,6 +10,8 @@ protected:
 
     Display *display;
 
+    microseconds_t clock;
+
 public:
 
     explicit Mode(Display *display) :
@@ -21,7 +23,7 @@ public:
 
     virtual const char *getName() = 0;
 
-    virtual void step(millis_t dt) = 0;
+    virtual void step(microseconds_t dt) = 0;
 };
 
 #endif
diff --git a/src/mode/Pong/Pong.h b/src/mode/Pong/Pong.h
index ca24ca8..183db84 100644
--- a/src/mode/Pong/Pong.h
+++ b/src/mode/Pong/Pong.h
@@ -36,7 +36,7 @@ public:
       return "Pong";
     }
 
-    void step(millis_t dt) override {
+    void step(microseconds_t dt) override {
 
     }
 
diff --git a/src/mode/SpaceInvaders/SpaceInvaders.h b/src/mode/SpaceInvaders/SpaceInvaders.h
index bff3d84..e19306a 100644
--- a/src/mode/SpaceInvaders/SpaceInvaders.h
+++ b/src/mode/SpaceInvaders/SpaceInvaders.h
@@ -22,7 +22,7 @@ class SpaceInvaders : public Mode {
 
 private:
 
-    millis_t heroRuntime = 0;
+    microseconds_t heroRuntime = 0;
     uint8_t heroX = 0;
     bool heroLeft = false;
     uint8_t heroShoot = 0;
@@ -31,7 +31,7 @@ private:
     uint8_t invadersCountY;
     uint8_t invadersAlive = 0;
 
-    millis_t swarmRuntime = 0;
+    microseconds_t swarmRuntime = 0;
     uint8_t swarmY = 0;
     bool swarmLeft = false;
     bool swarmDown = false;
@@ -39,7 +39,7 @@ private:
     Invader *swarmBegin;
     Invader *swarmEnd;
 
-    millis_t rocketRuntime = 0;
+    microseconds_t rocketRuntime = 0;
     Rocket *rocketsBegin;
     Rocket *rocketsEnd;
 
@@ -68,7 +68,7 @@ public:
       return "Space Invaders";
     }
 
-    void step(millis_t dt) override {
+    void step(microseconds_t dt) override {
       stepRockets(dt);
       stepInvaders(dt);
       stepHero(dt);
@@ -86,10 +86,10 @@ public:
       }
     }
 
-    void stepRockets(millis_t dt) {
+    void stepRockets(microseconds_t dt) {
       rocketRuntime += dt;
-      if (rocketRuntime > 200) {
-        rocketRuntime -= 200;
+      if (rocketRuntime > 200000) {
+        rocketRuntime -= 200000;
         for (Rocket *rocket = rocketsBegin; rocket < rocketsEnd; rocket++) {
           if (rocket->alive) {
             if (rocket->y == 0) {
@@ -108,16 +108,16 @@ public:
       }
     }
 
-    void stepInvaders(millis_t dt) {
+    void stepInvaders(microseconds_t dt) {
       swarmRuntime += dt;
 
-      if (swarmDown && swarmRuntime > 500) {
+      if (swarmDown && swarmRuntime > 500000) {
         swarmDown = false;
         swarmY++;
       }
 
-      if (swarmRuntime >= 1000) {
-        swarmRuntime -= 1000;
+      if (swarmRuntime >= 1000000) {
+        swarmRuntime -= 1000000;
         if (swarmLeft) {
           swarmX--;
           if (swarmX == 0) {
@@ -135,10 +135,10 @@ public:
       }
     }
 
-    void stepHero(millis_t dt) {
+    void stepHero(microseconds_t dt) {
       heroRuntime += dt;
-      if (heroRuntime >= 50) {
-        heroRuntime -= 50;
+      if (heroRuntime >= 50000) {
+        heroRuntime -= 50000;
         if (heroLeft) {
           heroX--;
           if (heroX <= 1) {
diff --git a/src/mode/Test/Border.h b/src/mode/Test/Border.h
index b4a942c..84a5f73 100644
--- a/src/mode/Test/Border.h
+++ b/src/mode/Test/Border.h
@@ -18,7 +18,7 @@ public:
       return "Border";
     }
 
-    void step(millis_t dt) override {
+    void step(microseconds_t dt) override {
       for (int y = 0; y < display->height; y++) {
         for (int x = 0; x < display->width; x++) {
           if (x == 0 || x == display->width - 1 || y == 0 || y == display->height - 1) {