Update 'Autodriving/motortest_first.ino'

Autodriving/motortest_first.ino

@@ -29,6 +29,7 @@ float duration;
 //calculating speed of sound uses floats and multiplications we don't want to bog down
 // our already slow and weak cpu so i use a the variables bellow along with function millis()
 // to take measurments every half minute (still too often in my opinion)
+// (also you can't  get readings more often than 2 seconds from this sensor)
   
 unsigned long temp_startcnt;
 unsigned long temp_currcnt;