arduino keypad wait for key
//update instances and possibly fire funcitons
void loop(){
char key1 = keypad.getKey();
char key2 = keypad2.getKey();
if (key1 != NO_KEY || key2 != NO_KEY){
Serial.print("You pressed: ");
Serial.print(key1 != NO_KEY ? key1 : "nothing on keypad");
Serial.print(" and ");
Serial.print(key2 != NO_KEY ? key2 : "nothing on keypad2");
Serial.println(".");
}
}