diff --git a/src/app/app.ino b/src/app/app.ino
index 0210e96..00091cd 100644
--- a/src/app/app.ino
+++ b/src/app/app.ino
@@ -103,6 +103,7 @@ void loop()
 
     sab.getScreenManager().displayView();
 
+    if(ioStateChange) Serial.println(F("ISR triggered"));
     ioStateChange = false;
   }