Cool! Would you be willing to share the debounce function you wrote? I might need to debounce a breakbeam that I'm working on.

Hey Muriel, sure thing. 1st off though you really need the two 0.1uf caps and the 10k resistors at ground, because it eliminates any spikes from in-rush current at switch press (that's the hardware part,) now the software part;

//Variables will change
int ledState = HIGH;        //current state of the output pin
int buttonState;            //current reading from the input pin
int lastButtonState = LOW;  //the previous reading from the input pin

unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

void loop() {
  //read the state of the switch into local variable
  int reading = digitalRead(button_1);/*Name U defined as "button"*/
  int reading = digitalRead(button_2);

  // check to see if U pressed the button
  //(i.e Input went from LOW to HIGH)

  // if switch changed, due to noise or pressing:
  if (reading != lastButtonState) {
    // reset the debouncing timer
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    //whatever the reading is at, it's been there for longer
    // than the debounce delay, so take it as the actual current state:

    // if the button state has changed:
    if (reading != buttonState) {
      buttonState = reading;

      // only toggle the LED if the new button state is HIGH
      if (buttonState == HIGH) {
        ledState = !ledState;

 Here is the entire code:

/*The circuit and code modified by me on 5/15/2017
  David H Haffner Sr as part of my prototype triple
  turret grating assembly, for my project 3D-Printable Raman Spectrometer
  http://hackaday.io/project/18126-3d-printable-raman-spectrometer
  The circuit as it stands now on a Mega 2560:
   LCD RS pin to digital pin 8
   LCD Enable pin to digital pin 9
   LCD D4 pin to digital pin 7
   LCD D5 pin to digital pin 6
   LCD D6 pin to digital pin 5
   LCD D7 pin to digital pin 4
   LCD R/W pin to ground
   LCD VSS pin to ground
   LCD VCC pin to 5V
   10K resistor:Trimmer POT
   ends to +5V and ground
   wiper to LCD VO pin (pin 3)

  Library originally added 18 Apr 2008
  by David A. Mellis
  library modified 5 Jul 2009
  by Limor Fried (http://www.ladyada.net)
  example added 9 Jul 2009
  by Tom Igoe
  modified 22 Nov 2010
  by Tom Igoe

  This example code is in the public domain.

  http://www.arduino.cc/en/Tutorial/LiquidCrystal
*/

// include the library code:

#include
#include
#include

const int button_1 = 1;// variable for storing button's status(this is for my referene :))
const int button_2 = 0;// variable for storing button's status
const int ledPin = 13;
const int motorPin1 = 12;// IN1 on motor control board
const int motorPin2 = 11;// IN2
const int motorPin3 = 10;// IN3
const int motorPin4 =  9; // IN4

//Variables will change
int ledState = HIGH;        //current state of the output pin
int buttonState;            //current reading from the input pin
int lastButtonState = LOW;  //the previous reading from the input pin

unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

int val1 = 0;
int val2 = 0;

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(21, 20, 19, 18, 17, 16);

const int stepsPerRevolution = 200;
//   Here set the stepper motor rotation step how much is a circle

int dim = stepsPerRevolution;
//  Set the step motor number and pin

Stepper myStepper(stepsPerRevolution, 13, 12, 11, 10);

void setup() {

  pinMode(3, INPUT_PULLUP);//Sets the buttons as input
  pinMode(ledPin, OUTPUT);
  pinMode(2, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);
  //set initial LED state
  digitalWrite(ledPin, ledState);
  attachInterrupt(1, counterclockwise, FALLING);
  attachInterrupt(0, clockwise, FALLING);

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

  lcd.setCursor(10, 0);

  lcd.print("n/min");

  lcd.setCursor(0, 1);
  lcd.print("Direction:");

}

void loop() {
  //read the state of the switch into local variable
  int reading = digitalRead(button_1);
  int redaing = digitalRead(button_2);

  // check to see if U pressed the button
  //(i.e Input went from LOW to HIGH)

  // if switch changed, due to noise or pressing:
  if (reading != lastButtonState) {
    // reset the debouncing timer
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    //whatever the reading is at, it's been there for longer
    // than the debounce delay, so take it as the actual current state:

    // if the button state has changed:
    if (reading != buttonState) {
      buttonState = reading;

      // only toggle the LED if the new button state is HIGH
      if (buttonState == HIGH) {
        ledState = !ledState;

      }
    }
  }
  myStepper.step(dim);
  void Direction();
  //  Read the sensor values:
  int sensorReading = analogRead(A0);
  //  Map it to a range of 0-150:
  int motorSpeed = map(sensorReading, 0, 1023, 0, 150);
  //  Set the motor speed:
  if (motorSpeed > 0)
    Serial.begin(115200);

  val1 = digitalRead(1);
  if (val1 == HIGH)

    val2 = digitalRead(0);
  if (val2 == HIGH)

  {

    myStepper.setSpeed(motorSpeed);
    lcd.setCursor(6, 0);
    lcd.print(float(float(motorSpeed) / float(200)));

  }

}

void clockwise()
{
  //   clockwise rotation
  dim = stepsPerRevolution;
  lcd.setCursor(10, 1);
  lcd.print(">>>>>>");

}

void counterclockwise()
{
  // anti-clockwise
  dim = -stepsPerRevolution;
  lcd.setCursor(10, 1);
  lcd.print("<<<<<<");
}