if i understand you your asking for a list of coodcard bar code's
I was asking if you had created an array of such values in your code. If not, you can modify goodCards and use those values:
char *goodCards = { "3455192327218", "4005209057240", "5060048310337" };
After this:
if(dataValue == SCAN_ENTER){
Serial.print("\nbuffer: ");
Put this:
int goodMatch = -1;
for(int c=0; c<cardCnt; c++)
{
if(strcmp(buffer, goodCards[c]) == 0)
{
goodMatch = c;
break;
}
}
Serial.print("goodMatch = ");
Serial.println(goodMatch); // Will print index of good card in array