diff --git a/Processors/PyBoard/Examples/Grove/Ultrasonic 2.py b/Processors/PyBoard/Examples/Grove/Ultrasonic 2.py
index 60a28db..3fe3c76 100644
--- a/Processors/PyBoard/Examples/Grove/Ultrasonic 2.py	
+++ b/Processors/PyBoard/Examples/Grove/Ultrasonic 2.py	
@@ -13,6 +13,9 @@
 
 dio = Pin('Y9')
 
+# referenced arduino/ultrasonic.h library for timeout number 
+_TIMEOUT2 = 1000000
+
 def _get_distance():
      dio.init(Pin.OUT)
      dio.value(0)
@@ -36,4 +39,4 @@ def get_distance():
 print('Detecting distance...')
 while True:
         print('{} cm'.format(get_distance()))
-        utime.sleep(1)
\ No newline at end of file
+        utime.sleep(1)