diff --git a/libraries/AP_HAL_PX4/examples/simple/simple.pde b/libraries/AP_HAL_PX4/examples/simple/simple.pde
index 64379581e6..6b812258f8 100644
--- a/libraries/AP_HAL_PX4/examples/simple/simple.pde
+++ b/libraries/AP_HAL_PX4/examples/simple/simple.pde
@@ -22,6 +22,7 @@
 #include <AP_Compass.h>
 #include <AP_Declination.h>
 #include <SITL.h>
+#include <AP_Notify.h>
 
 const AP_HAL::HAL& hal = AP_HAL_BOARD_DRIVER;