You almost had it.....this is the solution and even just simpler. Note that you were resetting the "readerdata" every time and it will hold the number entered on the keypad, no need for the variable Val
--- Petur ----
const int data0 = 0; // Interrupt 0, digital pin 2
const int data1 = 1; // Interrupt 1, digital pin 3
int nums = 0;
volatile long readerdata = 0;
void setup() {
attachInterrupt(data0, readerdata0, CHANGE);
attachInterrupt(data1, readerdata1, CHANGE);
Serial.begin(9600);
Serial.println("\n--Ready--");
}
void readerdata0() {
int status = digitalRead(data0+2);
if (status == LOW)
readerdata = readerdata << 1;
else if (digitalRead(data1+2) == HIGH) {
nums++;
}
}
void readerdata1() {
int status = digitalRead(data1+2);
if (status == LOW)
readerdata = (readerdata << 1) | 1;
else if (digitalRead(data0+2) == HIGH) {
nums++;
}
}
void loop() {
if(nums == 4) {
Serial.println(readerdata);
nums = 0;
readerdata = 0;
}
}