diff --git a/lib/treppe/treppe.cpp b/lib/treppe/treppe.cpp
index a3ab19b..9cb1e85 100644
--- a/lib/treppe/treppe.cpp
+++ b/lib/treppe/treppe.cpp
@@ -140,7 +140,8 @@ bool Treppe::read_sensor(int sensor)
   //return static_cast<bool>(pegel);
 }
 
-float Treppe::read_ldr(){
+float Treppe::read_ldr()
+{
   /* 
   Reads Illuminance in Lux
 
@@ -176,27 +177,28 @@ float Treppe::read_ldr(){
   return ldr_value;
 }
 
-
 bool Treppe::check_ldr()
 {
-  uint8_t active = 0;
+  static uint8_t active = 0;
 
-  #ifdef LDRDEBUG
+#ifdef LDRDEBUG
   Serial.printf("R(LDR) = %f kOhm  %f lux\n", ldr_value, lux);
   return true;
-  #endif
+#endif
 
   // follow up: averaging over many samples?
-  if(read_ldr() < ldr_schwelle) active = 1;
-  if(read_ldr() > ldr_schwelle + LDR_HYS) active = 0;
+  float ldr = read_ldr();
+  if (ldr < ldr_schwelle)
+    active = 1;
+  if (ldr > ldr_schwelle + LDR_HYS)
+    active = 0;
 
-  return active; 
+  return active;
 }
 
 void Treppe::task()
 {
-  //Serial.printf("LDR: %f\n", ((float)analogRead(A0))/1023.*3.68);
-  fsm_inputs.ldr_schwelle = read_ldr(); // <=== LDR implementierung !!
+  fsm_inputs.ldr_schwelle = check_ldr();
 
   fsm_inputs.sensor_oben = read_sensor(SENSOR_OBEN);
   fsm_inputs.sensor_unten = read_sensor(SENSOR_UNTEN);