diff --git a/buzzer.sh b/buzzer.sh
old mode 100644
new mode 100755
index 17a7c80..c8b2dc0
--- a/buzzer.sh
+++ b/buzzer.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 
+# set gpio number
 gpio=0
 
 $(command -v gpio) mode IN $gpio
@@ -17,4 +18,4 @@ while true; do
 
 	fi
 
-done
\ No newline at end of file
+done