diff --git a/src/BaseMQ.h b/src/BaseMQ.h
index c14c16a..24b7398 100644
--- a/src/BaseMQ.h
+++ b/src/BaseMQ.h
@@ -27,7 +27,7 @@
 #if defined(__AVR__)
 #define OPERATING_VOLTAGE   5.0
 
-#elif defined(__SAM3X8E__) || defined(__SAM3A8C__) || defined(__SAM3A4C__) || defined(__SAMD21G18A__)
+#elif defined(__SAM3X8E__) || defined(__SAM3A8C__) || defined(__SAM3A4C__) || defined(__SAMD21G18A__) || defined(ARDUINO_ARCH_ESP8266) || defined(__arm__)
 #define OPERATING_VOLTAGE   3.3
 #endif