It seems to me it already have a "keyPadEvent" function (interrupt) that is filled with some special cases already.
I have never used that library, but I guess the simplest solution is to have your 5-digit input in a global array, and work with that array in the keyPadEvent routine for your use. Just expand on that KeyPadEvent.
Something like this (untested, uncomplete example, just a suggestion):
#include <Keypad.h>
const int maxDigits = 5; // nr. of digits to enter
byte inputDigits[maxDigits]; // array of digits
int digitsEntered = 0; // nr. of digits entered via keypad
const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
char keys[ROWS][COLS] = {
{'1','2','3','A'},
{'4','5','6','B'},
{'7','8','9','C'},
{'#','0','*','D'}
};
byte rowPins[ROWS] = {2,3,4,5}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {6,7,8,9}; //connect to the column pinouts of the keypad
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
byte ledPin = 13;
boolean blink = false;
void setup(){
Serial.begin(9600);
pinMode(ledPin, OUTPUT); // sets the digital pin as output
digitalWrite(ledPin, HIGH); // sets the LED on
keypad.addEventListener(keypadEvent); //add an event listener for this keypad
}
void loop(){
char key = keypad.getKey();
if (key != NO_KEY) {
if (digitsEntered < maxDigits)
{
inputDigits[digitsEntered++] = key;
Serial.print(key);
}
}
if (blink){
digitalWrite(ledPin,!digitalRead(ledPin));
delay(100);
}
}
//take care of some special events
void keypadEvent(KeypadEvent key){
switch (keypad.getState()){
case PRESSED:
switch (key){
case '#': digitalWrite(ledPin,!digitalRead(ledPin)); break;
case '*':
digitalWrite(ledPin,!digitalRead(ledPin));
break;
}
break;
case RELEASED:
switch (key){
case 'A': // erase digit
if (digitsEntered > 0)
{
inputDigits[--digitsEntered] = 0; // erase digit (sort of..)
Serial.print(0x08) ; // backspace
}
break;
case 'B' // erase all digits
// more case B code...
digitsEntered = 0; // start over the array index
break;
case 'C': // Validate digits
if (digitsEntered == 5)
{
Serial.println(); // next line on serial
// more validate digits code
}
break;
}
break;
case HOLD:
switch (key){
case '*': blink = true; break;
}
break;
}
}