diff --git a/src/sds011read.cpp b/src/sds011read.cpp
index c55b5741..cf6dccdf 100644
--- a/src/sds011read.cpp
+++ b/src/sds011read.cpp
@@ -6,12 +6,16 @@ static const char TAG[] = __FILE__;
 #include <sds011read.h>
 
 // UART(2) is unused in this project
+#if (HAS_IF482)
+#error cannot use IF482 together with SDS011 (both use UART#2)
+#endif
 static HardwareSerial sdsSerial(2);    // so we use it here
 static SDS011 sdsSensor;               // fine dust sensor
 
 // the results of the sensor:
 float pm25;              
 float pm10;
+boolean isSDS011Active;
 
 // init
 bool sds011_init()
@@ -19,18 +23,40 @@ bool sds011_init()
     pm25 = pm10 = 0.0;
     sdsSerial.begin(9600, SERIAL_8N1, ESP_PIN_RX, ESP_PIN_TX);
     sdsSensor.begin (&sdsSerial);
-    sdsSensor.contmode(0);              // for safety: wakeup/sleep - if we want it we do it by ourselves
-    sdsSensor.wakeup();                 // always wake up
+    sdsSensor.contmode(0);              // for safety: no wakeup/sleep by the sensor
+    sds011_sleep();                     // we do it by ourselves
     return true;
 }
 // reading data:
 void sds011_loop()
 {
-    pm25 = pm10 = 0.0;
-    int sdsErrorCode = sdsSensor.read(&pm25, &pm10);
-    if (!sdsErrorCode) 
-    {
-        ESP_LOGD(TAG, "SDS011 error: %d", sdsErrorCode);
-    } 
+    if ( isSDS011Active ) {
+        int sdsErrorCode = sdsSensor.read(&pm25, &pm10);
+        if (sdsErrorCode) {
+            pm25 = pm10 = 0.0;
+            ESP_LOGI(TAG, "SDS011 error: %d", sdsErrorCode);
+        }
+        else {
+            ESP_LOGI(TAG, "fine-dust-values: %5.1f,%4.1f", pm10, pm25);
+        }
+        sds011_sleep();
+    }
     return;
 }
+
+// putting the SDS-sensor to sleep
+void sds011_sleep(void)
+{
+    sdsSensor.sleep();
+    isSDS011Active = false;
+}
+
+// start the SDS-sensor
+// needs 30 seconds for warming up
+void sds011_wakeup()
+{
+    if ( !isSDS011Active ) {
+        sdsSensor.wakeup();
+        isSDS011Active = true;
+    }
+}