diff --git a/src/main.cpp b/src/main.cpp
index e0f26a4..4243274 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1053,12 +1053,12 @@ void writeRoute(String topicStr) {
       double y = obj["tasks"][fc.writeSeq]["y"];
       double z = obj["tasks"][fc.writeSeq]["z"];
       String str = obj["tasks"][fc.writeSeq]["sound"];
-      if ((str!=NULL)&&(str != ""))
+      if ((str!=NULL)&&(str != "")&&(str != "null"))
       {
         fc.questVoiceStr = str;
-       // printf("writevoice str: %s \n", fc.questVoiceStr);
+        //printf("writevoice str: %s \n", fc.questVoiceStr);
        // if (fc.writeSeq==0) 
-        //  fhc.playText(fc.questVoiceStr);
+        //fc.playText(fc.questVoiceStr);
        }
       fc.logln((char*)"frame--");
       fc.logln(frame);