diff --git a/lib/obp60task/obp60task.cpp b/lib/obp60task/obp60task.cpp
index 531a81b..e99b228 100644
--- a/lib/obp60task/obp60task.cpp
+++ b/lib/obp60task/obp60task.cpp
@@ -1,4 +1,5 @@
 #ifdef BOARD_NODEMCU32S_OBP60
+#include <Arduino.h>
 #include "obp60task.h"
 #include "Pagedata.h"
 #include "OBP60Hardware.h"              // PIN definitions