diff --git a/src/main.cpp b/src/main.cpp
index a64b396..3dfac37 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -8,12 +8,12 @@
  *              GND O                    O GND
  *               5V O                    O 5V
  *              3V3 O                    O 3V3
- *              GND O                    < 36
+ *              GND O                    < 36           only input, no pullups
  *               RX *                    * 17
- *               TX *                    < 38 ROTARY_A
- *              RST * BUTTON             < 39 ROTARY_B
- *                0 * BUTTON             < 34
- *               22 *                    < 35
+ *               TX *                    < 38 ROTARY_A  only input, no pullups
+ *              RST * BUTTON             < 39 ROTARY_B  only input, no pullups
+ *                0 * BUTTON             < 34           only input, no pullups
+ *               22 *                    < 35           only input, no pullups
  * BME280_SDO    19 * LoRa_MISO       ?  * 32
  * BME280_CS     23 *                 ?  * 33
  *               18 x LoRa_CS            * 25 MAX98_DIN
@@ -313,5 +313,5 @@ void loop()
   u8g2.sendBuffer();
 //  bme280.printValues();
 
-  delay(100);
+  delay(200);
 }
diff --git a/src/rotary.cpp b/src/rotary.cpp
index 61d78b9..99c2386 100644
--- a/src/rotary.cpp
+++ b/src/rotary.cpp
@@ -1,13 +1,5 @@
  /* interrupt routine for Rotary Encoders
-   tested with Noble RE0124PVB 17.7FINB-24 http://www.nobleusa.com/pdf/xre.pdf - available at pollin.de
-   and a few others, seems pretty universal
-
-   The average rotary encoder has three pins, seen from front: A C B
-   Clockwise rotation A(on)->B(on)->A(off)->B(off)
-   CounterCW rotation B(on)->A(on)->B(off)->A(off)
-
-   and may be a push switch with another two pins, pulled low at pin 8 in this case
-   raf@synapps.de 20120107
+   idea from: https://github.com/marcmerlin/IoTuz/blob/95f53be6569c68f7fbef491bb36082870f82d629/IoTuz.cpp
 
 */
 
@@ -15,7 +7,11 @@
 
 //using namespace std;
 
-Rotary::Rotary() {}
+Rotary* Rotary::instance = NULL;
+
+Rotary::Rotary() {
+  instance = this;
+}
 
 bool Rotary::begin(uint8_t pinA, uint8_t pinB, uint8_t pinButton) {
   this->pinA = pinA;
@@ -25,9 +21,6 @@ bool Rotary::begin(uint8_t pinA, uint8_t pinB, uint8_t pinButton) {
   pinMode(pinB, INPUT_PULLUP);
   pinMode(pinButton, INPUT_PULLUP);
 
-  encoder = new ClickEncoder(pinA, pinB, pinButton, 4);
-  //encoder->setButtonOnPinZeroEnabled(true);
-
   xTaskCreate(
                     &cTaskWrapper,          /* Task function. */
                     "encoderTask",        /* String with name of task. */
@@ -35,6 +28,10 @@ bool Rotary::begin(uint8_t pinA, uint8_t pinB, uint8_t pinButton) {
                     this,             /* Parameter passed as input of the task */
                     tskIDLE_PRIORITY+2,                /* Priority of the task. */
                     &taskHandle);            /* Task handle. */
+
+  attachInterrupt(digitalPinToInterrupt(pinA), doEncoder, CHANGE);
+  attachInterrupt(digitalPinToInterrupt(pinB), doEncoder, CHANGE);
+
   return true;
 }
 
@@ -43,14 +40,13 @@ void Rotary::cTaskWrapper(void* parameters) {
 }
 
 void Rotary::task(void *pvParameters) {
+  xTaskToNotify = xTaskGetCurrentTaskHandle();
+  uint32_t ulNotificationValue;
   while(true) {
-    encoder->service();
-    value += encoder->getValue();
-    if (value != last) {
-      last = value;
-      if (callback) callback(value);
-    }
-    vTaskDelay(1 / portTICK_PERIOD_MS);
+    ulNotificationValue = ulTaskNotifyTake( pdFALSE, portMAX_DELAY );
+    int newPos = encoderPos/2;
+    if (lastPos != newPos)
+      if (callback) callback(newPos);
   }
   vTaskDelete(NULL);
 }
@@ -59,3 +55,28 @@ bool Rotary::registerCallback(std::function<void(int)> callback) {
   this->callback = callback;
   return true;
 }
+
+// Interrupt on changing state
+void Rotary::doEncoder() {
+  if ((millis() - instance->debounceMillis) > instance->debounceDelay) {
+    instance->debounceMillis = millis();
+
+    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+
+    static uint8_t old_AB = 0;
+    // grey code
+    // http://hades.mech.northwestern.edu/index.php/Rotary_Encoder
+    // also read up on 'Understanding Quadrature Encoded Signals'
+    // https://www.pjrc.com/teensy/td_libs_Encoder.html
+    // another interesting lib: https://github.com/0xPIT/encoder/blob/arduino/ClickEncoder.cpp
+    static int8_t enc_states[] = {0,-1,1,0,1,0,0,-1,-1,0,0,1,0,1,-1,0};
+
+    old_AB <<= 2;
+    old_AB |= ((digitalRead(instance->pinB))?(1<<1):0) | ((digitalRead(instance->pinA))?(1<<0):0);
+    instance->encoderPos += ( enc_states[( old_AB & 0x0f )]);
+
+    configASSERT( instance->xTaskToNotify != NULL );
+    vTaskNotifyGiveFromISR( instance->xTaskToNotify, &xHigherPriorityTaskWoken );
+    portYIELD_FROM_ISR(); //portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
+  }
+}
diff --git a/src/rotary.h b/src/rotary.h
index 209b58f..916602e 100644
--- a/src/rotary.h
+++ b/src/rotary.h
@@ -17,8 +17,13 @@ class Rotary {
     Rotary();
     bool begin(uint8_t pinA, uint8_t pinB, uint8_t pinButton);
     bool registerCallback(std::function<void(int)> callback);
-    ClickEncoder *encoder;
-    int16_t last, value;
+    static void IRAM_ATTR doEncoder(void);
+    static Rotary* instance;
+    volatile int encoderPos = 0;
+    int lastPos = 0;
+    uint32_t debounceMillis;
+    uint32_t debounceDelay = 1;
+    TaskHandle_t xTaskToNotify;
   private:
     uint8_t pinA;
     uint8_t pinB;