Switch Statement stuck in loop

Question

I am writing a code for a user to enter a 4 digit pin, then use this pin later to unlock a box. The loop is stuck between the "ready to unlock box" and "enter pin" it just keeps flipping between values but i want both to be displayed, just at different times.

#include <Keypad.h> //install keypad library
#include <LiquidCrystal.h> //install LCD screen library
const byte ROWS = 4; //include four rows of keypad
const byte COLS = 4; //indclude four cols of keypad
char keys[ROWS][COLS] = { //set keypad array equal to numbers on keypad
 {'1', '2', '3', 'A'},
 {'4', '5', '6', 'B'},
 {'7', '8', '9', 'C'},
 {'*', '0', '#', 'D'}
};
int pin1, pin2, pin3, pin4, pin5, pin6, pin7, pin8;
int code[] = {pin1, pin2, pin3, pin4};
byte rowPins[ROWS] = {45,43,41,39}; //connect to the row pins of keypad
byte colPins[COLS] = {37,35,33,31}; //connent to the column pins of keypad
LiquidCrystal lcd(7, 8, 9, 10, 11, 12); //set up pins lcd will be connected to
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS ); //set keypad up to use as variable
int solenoidPin = 1; //connect motor pin to code
bool in_press = false;
void setup() {
 Serial.begin(9600); //start code
 lcd.begin(16,2); //start screen with dimensions
}
void loop() //loop of functions to run through
{ 
 int key; //initialize key as integer
 lcd.setCursor(0,0);
 lcd.print("Press # to lock,");//welcome screen
 lcd.setCursor(0,1);
 lcd.print("or * to unlock.");
 key = keypad.getKey(); //let arduino know it is waiting for a value
 while (in_press && key == NO_KEY) //check if they want to begin
 { 
 in_press = false; //if no key was clicked 
 return; //exit the loop and restart
 }
 while (key != NO_KEY){ //if a key was clicked
 switch(key){
 case '#':
 lcd.clear();
 lcd.setCursor(0,0);
 *lcd.print("Ready to lock"); //let user know ready for next step of process
 lcd.setCursor(0,1);
 lcd.print("keys!");
 delay(1000);
 EnterPin1();
 break;*
 case '*':
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("Ready to unlock"); //let user know ready for next step of process
 lcd.setCursor(0,1);
 lcd.print("keys!");
 delay(1000);
 EnterPin5();
 break;
 default:
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("No input");
 lcd.setCursor(0,1);
 lcd.print("detected.");
 break;
 }
 }
}
void EnterPin1()
{
 Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
 bool in_press = false;
 int pin1;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("Enter your pin.");//let user know you are waiting for input
 delay(1000);
 pin1 = keypad.getKey(); //let arduino know it is waiting for a value
 while (in_press && pin1 == NO_KEY) //check if they want to begin
 { 
 in_press = false; //if no key was clicked 
 return; //exit the loop and restart
 }
 while (pin1 != NO_KEY) //if a key was clicked
 { 
 switch(pin1){
 case '1':
 pin1 = 1;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*"); //let user know ready for next step of process
 EnterPin2(); //go to enter pin function
 break;
 case'2':
 pin1 = 2;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*"); //let user know ready for next step of process
 delay(1000);
 EnterPin2();
 break;
 case '3': 
 pin1 = 3;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*");
 EnterPin2();
 break;
 case '4':
 pin1 = 4;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*");
 EnterPin2();
 break;
 case '5':
 pin1 = 5;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*");
 EnterPin2();
 break;
 case '6':
 pin1 = 6;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*");
 EnterPin2();
 break;
 case '7':
 pin1 = 7;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*"); 
 EnterPin2();
 break;
 case '8':
 pin1 = 8;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*");
 EnterPin2();
 break;
 case '9':
 pin1 = 9;
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("*");
 EnterPin2();
 break;
 }
 }
 } 

• MichaelT: The logic may be incorrect. Also try to make a en.wikipedia.org/wiki/Finite-state_machine which may avoid needing to define multiple functions EnterPin1, EnterPin2 3 etc.

Answer 1

Your primary loop code sets key, and then has a while (key != nokey) {} loop after, but the value of key never changes inside the while loop. Thus, if key is not equal to noKey, the while loop will never exit.

key = keypad.getKey();
while (key != noKey) {
 //code that does not change key
}

That is an endless loop. The fact that there’s a switch statement inside the while loop is immaterial. None of that code changes the value of key, so the loop will never exit.

Write it like this instead:

EDIT

key = keypad.getKey();
while (key != noKey) {
 //Your current code
 key = keypad.getKey();
}

You have the same logic problem in your enterPin1 function. You don’t provide the code for your enterPin2 function, but I would guess it also has the same logic problem.

• Nicole: That gives me error "expected ')' before ';' token", is there another part i should add in there?
• Duncan C: Ok, I wasn’t sure if that syntax was legal or not. Apparently not. I’m at a tablet where I don’t have access to a C compiler. You could use your code, but add a final ` key = kaypad.getKey()` as the last statement in your while loop to fetch another value for key before looping back again.
• Duncan C: See the edit to my answer. There’s a more elegant way to do this but I don’t have access to a compiler at the moment to get it right for you.