diff --git a/src/core/analogsensor.cpp b/src/core/analogsensor.cpp
index 6d4b3f59b..134c69977 100644
--- a/src/core/analogsensor.cpp
+++ b/src/core/analogsensor.cpp
@@ -26,8 +26,8 @@ std::vector<uint8_t> AnalogSensor::exclude_types_;
 
 #ifndef EMSESP_STANDALONE
 portMUX_TYPE  mux                     = portMUX_INITIALIZER_UNLOCKED;
-unsigned long AnalogSensor::edge[]    = {0, 0, 0};
-unsigned long AnalogSensor::edgecnt[] = {0, 0, 0};
+volatile unsigned long AnalogSensor::edge[]    = {0, 0, 0};
+volatile unsigned long AnalogSensor::edgecnt[] = {0, 0, 0};
 
 void IRAM_ATTR AnalogSensor::freqIrq0() {
     portENTER_CRITICAL_ISR(&mux);
diff --git a/src/core/analogsensor.h b/src/core/analogsensor.h
index 592452f96..31a7af0ec 100644
--- a/src/core/analogsensor.h
+++ b/src/core/analogsensor.h
@@ -210,8 +210,8 @@ class AnalogSensor {
     static void IRAM_ATTR freqIrq0();
     static void IRAM_ATTR freqIrq1();
     static void IRAM_ATTR freqIrq2();
-    static unsigned long  edge[3];
-    static unsigned long  edgecnt[3];
+    static volatile unsigned long edge[3];    // written from freqIrqN() ISRs, read from the main measure() loop (partly outside the critical section)
+    static volatile unsigned long edgecnt[3]; // written from freqIrqN() ISRs, read from the main measure() loop (partly outside the critical section)
     unsigned long         lastedge[3] = {0, 0, 0};
 #endif
 };