Scroll String Only On Second Line Using 2x16 LCD I'm trying to scroll a string in the second row of the LCD while letting the string on the first row stay intact. I use Serial to run that part of the code as you can see. It work at first but when I try to make it run again it doesn't display anything on the second row.

I borrowed the code from :

http://code.nishantarora.in/arduino-lcd-projects/src/3f10686e7464665c5c59d7be772c00af7a4a93e8/scrollOneLine/scrollOneLine.ino?at=master

And made some changes:

// include the library
#include &lt;LiquidCrystal.h&gt;

// init the lcd display according to the circuit
LiquidCrystal lcd(9, 8, 7, 6, 5, 4);

// it's a 16x2 LCD so...
int screenWidth = 16;
int screenHeight = 2;

String line1;
String line2;

int stringStart, stringStop = 0;
int scrollCursor = screenWidth;

String CompleteString;
String stringArray[] = {"s=Plane", "i=Car", "h=Boat", "u=Rocket", "d=Jet",  "p=Submarine", "l=Truck", "b=Bicycle", "m=Skate", "enter=Train"};

String string1 = "String";

int countMovement=0;
int arraylimit = 9;

void setup() {

   lcd.begin(screenWidth,screenHeight);
   Serial.begin(9600);

}

void loop(){

   char ser = Serial.read();

   if ( ser == 'c' ) {  
     CompleteString="";

     for (int i = 0 ; i &lt;= arraylimit; i++) {
        CompleteString += stringArray[i] + " "; // Convert String Array To Single String
     }

     roop(string1,CompleteString);
  }

}

void roop(String line1, String line2) {

  countMovement = 0;

  while ( ( countMovement ) &lt; (line2.length() + screenWidth )  ) {

     lcd.setCursor(scrollCursor, 1);
     lcd.print(line2.substring(stringStart,stringStop));
     lcd.setCursor(4, 0); // 1 = word eat array of words very cool
     lcd.print(line1);
     delay(300);
     lcd.clear();

     if(stringStart == 0 &amp;&amp; scrollCursor &gt; 0){
        // Serial.println(scrollCursor);     
        scrollCursor--;
        stringStop++;
     } else if (stringStart == stringStop){
        stringStart = stringStop = 0;
        scrollCursor = screenWidth;
     } else if (stringStop == line1.length() &amp;&amp; scrollCursor == 0) {
        stringStart++;
     } else {
       stringStart++;
       stringStop++;
     }

     countMovement++;

  }

  lcd.setCursor(4, 0);
  lcd.print(line1);

}


From what I can see using Serial as debugging is that the problem resides in the function "roop" and in specific the line:

 if(stringStart == 0 &amp;&amp; scrollCursor &gt; 0){


It seems that the statement is being pass on and so it doesn't move the string as it's suppose to. I could be wrong but placing a Serial call in there yields no result the second time the function is called but the first time it did.

Any help would be much appreciated! And I know the community will be grateful too since it's difficult from what I can see in post to achieve this and make it autonomous so that no big modifications needs to be done.
You need to reset the stringStart, stringStop and scrollCursor at the beginning of the roop function.

void roop(String line1, String line2) {

  countMovement = 0;
  stringStart = 0;
  stringStop = 0;
  scrollCursor = screenWidth;

  ...


I think you also need to move the lcd.clear up. Or else the screen will be blanked when the roop function is done scrolling.

...

  while ( ( countMovement ) &lt; (line2.length() + screenWidth )  ) {

     lcd.clear();
     lcd.setCursor(scrollCursor, 1);
     lcd.print(line2.substring(stringStart,stringStop));
     lcd.setCursor(4, 0); // 1 = word eat array of words very cool
     lcd.print(line1);
     delay(300);

...