stepper with keypad, how to "hold" numbers

Projects General Guidance
1

Hello. I've got a code where i want to input a number into my keypad, have the code "hold" or record that number, then use it to tell my stepper how many steps to go. So im inputting say 2 for 2 inches, that gets converted to steps and makes the stepper run. I've got a VERY, VERY ugly code right now but i just simply put everything together (see below), so please dont judge too harshly. I just want to know how do i input a number through a keypad to use to move my stepper to that length/position.

Thanks so much in advance. I'm still very new but i'm trying not to ask too much! I'm using the Arduino Mega.

#include <Keypad.h>
#include <LiquidCrystal.h>

//----- Encoder ----

int rs = 22, en = 23, d4 = 24, d5 = 25, d6 = 26, d7 = 27;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

int pulses;
int encoderA = 2;
int encoderB = 3;
int pulsesChanged = 0;

//----- LCD ----

const byte ROWS = 4; // Four rows
const byte COLS = 3; // Three columns
// Define the Keymap
char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'#','0','*'}
};
// Connect keypad ROW0, ROW1, ROW2 and ROW3 to these Arduino pins.
byte rowPins[ROWS] = { 31, 32, 33, 34 };
// Connect keypad COL0, COL1 and COL2 to these Arduino pins.
byte colPins[COLS] = { 28, 29, 30 }; 
// Create the Keypad
Keypad kpd = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

// ----- Stepper ----

// defines pins numbers
const int stepPin = 35; 
const int dirPin = 36; 
const int enPin = 37;

void setup(){
  pinMode(encoderA, INPUT);
  pinMode(encoderB, INPUT);  
  pinMode(stepPin,OUTPUT); 
  pinMode(dirPin,OUTPUT);  
  pinMode(enPin,OUTPUT);
  digitalWrite(enPin,LOW);
  
  attachInterrupt(0, A_CHANGE, CHANGE);

   // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("Test Circuit");

}//setup

void loop(){
  char key = kpd.getKey();
  lcd.setCursor(9, 1);
  if (key){
    lcd.setCursor(9,1);
    lcd.print("key= ");
    lcd.print(key);
  }       
  if (pulsesChanged != 0) {
    pulsesChanged = 0;
    lcd.setCursor(0, 1);
    lcd.print(pulses);
      }

  digitalWrite(dirPin,HIGH); // Enables the motor to move in a particular direction
  // Makes 200 pulses for making one full cycle rotation
  for(int x = 0; x < 800; x++) {
    digitalWrite(stepPin,HIGH); 
    delayMicroseconds(500); 
    digitalWrite(stepPin,LOW); 
    delayMicroseconds(500); 
  }
  delay(1000); // One second delay
  
  digitalWrite(dirPin,LOW); //Changes the rotations direction
  for(int x = 0; x < 800; x++) {
    digitalWrite(stepPin,HIGH);
    delayMicroseconds(500);
    digitalWrite(stepPin,LOW);
    delayMicroseconds(500);
  }
  delay(1000);
}

void A_CHANGE(){
  if( digitalRead(encoderB) == 0 ) {
    if ( digitalRead(encoderA) == 0 ) {
      // A fell, B is low
      pulses--; // moving reverse
    } else {
      // A rose, B is low
      pulses++; // moving forward
    }
 } 
 
  // tell the loop that the pulses have changed
  pulsesChanged = 1;
}
2

You have the key value here:

  if (key){
    lcd.setCursor(9,1);
    lcd.print("key= ");
    lcd.print(key);
  }

so do something with it.

Subtract ASCII zero '0' to convert to a decimal digit, then store that digit in an array, or accumulate a larger number from successive digits until "end of input" key is encountered, etc.

This problem has been solved millions of times, so a little time spent with Mr. Google should turn up plenty of examples.