DRO Scale with Arduino

//If you found my video helpful, please SUBSCRIBE:  https://www.youtube.com/channel/UCKp1MzuAceJnDqAvsZl_46g
//The code belongs to the following tutorial video: https://youtu.be/mFWOOtJPVAs

/*
Please consider buying the parts using the following links to support me:
JCS-900 DRO: https://www.banggood.com/custlink/mGGv0HttR8
D-SUB 9 pin 10 pcs (both): https://www.banggood.com/custlink/vm33etFthU
D-SUB 9 pin extension board (Female): https://www.banggood.com/custlink/mmmmBtttR1
D-SUB 9 pin extension board (Male): https://www.banggood.com/custlink/3mGK6F5FcK
16x2 LCD (I2C): https://www.banggood.com/custlink/KmGGgtP2Lv
DSO-150 Oscilloscope: https://www.banggood.com/custlink/3m3D80wzMy
Oscilloscope probe (1 pc): https://www.banggood.com/custlink/vDDDigTMUW
Arduino UNO: https://www.banggood.com/custlink/33KKF85c3i
*/

//length: 50 mm = 50000 um
//resolution: 5 um
//steps: 50000 um / 5 um = 10000
//REMEMBER! You have to calibrate your scale to get precise values in physical units
//You only get increments here and you have to calibrate the increments

#define encoder0PinA  2 //Pin 2 is one of the pins which works with attachInterrupt() on Arduino UNO
#define encoder0PinB  4

volatile int encoder0Pos = 0; //Position of the encoder
boolean newdata = false; //Flag to see if there's new data (the encoder was moved)

#include <Wire.h> //for I2C
#include <LiquidCrystal_I2C.h> //LCD's own library
LiquidCrystal_I2C lcd(0x27, 16, 2); //initializing LCD
//2 lines, 16 Characters per line
//-----------------------------------------------------------------------

void setup() {
  pinMode(encoder0PinA, INPUT); //Pin 2 = Input
  digitalWrite(encoder0PinA, HIGH);       // turn on pull-up resistor
  pinMode(encoder0PinB, INPUT); //Pin 4 = Input
  digitalWrite(encoder0PinB, HIGH);       // turn on pull-up resistor

  attachInterrupt(0, doEncoder, CHANGE);  // encoder pin on interrupt 0 - pin 2
  Serial.begin (9600);
  Serial.println("DRO testing");                // start message
  //------------------------------------------------------
  lcd.init();                      // initialize the lcd
  lcd.init();
  lcd.backlight();
  //------------------------------------------------------
  //------------------------------------------------------
  //fancy startup process, "animation" with the dots on the screen. You can skip this section
  lcd.clear(); //clear lcd
  lcd.setCursor(0,0); //Defining positon to write from. first row,first column .
  lcd.print("DRO Scale");
  lcd.setCursor(0,1); //Defining positon to write from. second row,first column .
  lcd.print("Starting.");
  delay(300);
  lcd.setCursor(0,1);
  lcd.print("Starting..");
  delay(300);
  lcd.setCursor(0,1);
  lcd.print("Starting...");
  delay(300);
  lcd.setCursor(0,1);
  lcd.print("Starting....");
  delay(300);
  lcd.setCursor(0,1);
  lcd.print("Starting.....");
  delay(300);
  //------------------------------------------------------
  //Printing the fixed text on the screen
    lcd.clear();
    lcd.setCursor(0,0); //1st row, 1st place
    lcd.print("DRO Scale");
    lcd.setCursor(0,1); //2nd row, 1st place
    lcd.print("Position: ");

}

void loop()
{
  if(newdata == true) //if the encoder was moved
  {
    lcd.clear(); //clean the screen to avoid mess (i.e. we try to print "999" after "1000", we don't want to see "9990")
    lcd.setCursor(0,0);
    lcd.print("DRO Scale");
    lcd.setCursor(0,1);
    lcd.print("Position: ");
    lcd.setCursor(10,1); //we move the cursor after the "Position: " part and start printing from there
    lcd.print(encoder0Pos); //we print the number based on the position
  }

  newdata = false; //we switch the flag to 'false' so the Arduino will not do anything until a new data comes in
}

void doEncoder() //if the attachInterrupt() is triggered, this function runs
{
   if (digitalRead(encoder0PinA) == digitalRead(encoder0PinB)) //if the Arduino saw the square waves' rising edge
  {
    encoder0Pos++; // increase the position
  } else {
    encoder0Pos--; //otherwise decrease the position
  }
  newdata = true; //we change this flag, so the if statement in the loop() will run and the data will be printed
  Serial.println(encoder0Pos, DEC); //sending the data to the PC. This can be moved in to the loop()'s if()
}