Stopwatch timer 3 digits after seconds

Using Arduino Programming Questions
1

Hello there, I want timer stopwatch for Arduino Uno and LCD I2C display.
Code now working that: MINUTEMINUTE:SECONDSSECONDS:DIGIT i want MINUTEMINUTE:SECONDSSECONDS:DIGITDIGITDIGIT Is it possible with millis or must i use micros? Can someone make a example code for that?
Code for try it at you: I want 00:00:000 instead of 00:00:0.

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define I2C_ADDR    0x3F  // Define I2C Address where the PCF8574A is
                          // Address can be changed by soldering A0, A1, or A2
                          // Default is 0x27

// map the pin configuration of LCD backpack for the LiquidCristal class
#define BACKLIGHT_PIN 3
#define En_pin  2
#define Rw_pin  1
#define Rs_pin  0
#define D4_pin  4
#define D5_pin  5
#define D6_pin  6
#define D7_pin  7

LiquidCrystal_I2C lcd(I2C_ADDR,
                      En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin,
                      BACKLIGHT_PIN, POSITIVE);

const int spustacresettlacidlo = 12;     //The pin for spustacresettlacidlo

long lastPressedspustacresettlacidlo = 0;    //Last millisecond we pressed spustacresettlacidlo

boolean run = false;         //Should the system run?

int spustacresettlacidloState = LOW;      //The value the spustacresettlacidlo reads
int spustacresettlacidloCurrState = LOW;  //The last value of spustacresettlacidlo



long timer = 0; //The timer

int second = 0;
int minute = 0;
int tenth = 0;


void setup() {
  lcd.begin(20, 4);                // intialise the LCD.
     lcd.setBacklight(HIGH); // Turn on backlight, LOW for off
  pinMode(spustacresettlacidlo, INPUT);
  lcd.setCursor(0,0);
  lcd.print("00:00:0 L");
   lcd.setCursor(0,1);
   lcd.print("00:00:0 P");

}

void tickClock() {
  Serial.println(millis() /10);
  if((timer - millis()/100) >= 100 || timer == 0) {
    tick();
    timer = millis()/100;
  }
}

void loop() {
  tickClock(); //Start ticking the clock
  spustacresettlacidloState = digitalRead(spustacresettlacidlo);
  checkStart();
}

void checkStart() {
  if(spustacresettlacidloState != spustacresettlacidloCurrState) {    //Check if the button state has changed
    if(spustacresettlacidloState == HIGH && (millis()-lastPressedspustacresettlacidlo) > 100 || lastPressedspustacresettlacidlo == 0) {
      lastPressedspustacresettlacidlo = millis();
      run = !run; //Switch the running state
    }    
  }
  spustacresettlacidloCurrState = spustacresettlacidloState;    //Set the current state equals the button state
}


void tick() {
  if(run) {
    updateLCD();
    
    
    
    if(tenth == 9) {
      tenth = 0;
      
      if(second == 59) {
        second = 0;
        minute++;
        
      } else {
        second++;
      }
    } else {
    tenth++;
    }
  }
}

void updateLCD() {
  //
   lcd.setCursor(0,0);
  if(minute < 10) {      // If hour does not have 2 digits
    lcd.print("0");
  }
  lcd.print(minute, DEC);
  lcd.print(":");

  if(second < 10) {    // If minute does not have 2 digits
    lcd.print("0");
  }
  lcd.print(second, DEC);
  lcd.print(":");

  lcd.print(tenth, DEC); 
  //
  lcd.setCursor(0,1);
  if(minute < 10) {      // If hour does not have 2 digits
    lcd.print("0");
  }
  lcd.print(minute, DEC);
  lcd.print(":");

  if(second < 10) {    // If minute does not have 2 digits
    lcd.print("0");
  }
  lcd.print(second, DEC);
  lcd.print(":");

  lcd.print(tenth, DEC); 
}

Sorry for bad english. I want it for stopwatch for firesport. Thanks a lot! I dont have experiences with time.
Photo of actual project:

3840×2160 417 KB

2 
void tickClock() {
  Serial.println(millis() /10);
  if((timer - millis()/100) >= 100 || timer == 0) {
    tick();
    timer = millis()/100;
  }
}

should be

void tickClock() {
  if (millis() - timer > 0) 
  {
    timer += 1 ;
    tick();
  }
}

And then you need to call "tenth" "thousandth", and print all 3 of its digits:

  lcd.print (thousandth/100) ;
  lcd.print (thousandth/10%10) ;
  lcd.print (thousandth%10) ;
3

MarkT:

void tickClock() {

Serial.println(millis() /10);
  if((timer - millis()/100) >= 100 || timer == 0) {
    tick();
    timer = millis()/100;
  }
}



should be

void tickClock() {
  if (millis() - timer > 0)
  {
    timer += 1 ;
    tick();
  }
}



And then you need to call "tenth" "thousandth", and print all 3 of its digits:

lcd.print (thousandth/100) ;
  lcd.print (thousandth/10%10) ;
  lcd.print (thousandth%10) ;

I think that this approach might well be doomed to fail.
You are attempting to write to the display 1000 times per second, using probably a rather inefficient library, no less. My guess is that this would cause the clock would fall far behind.
Probably better to stick to displaying tenths of a second when the clock is running, and only show thousandths when paused or stopped.

4

No, working bad. :frowning: Can you try to fill whole code with that? There is function, where there are increment of each variable..

5

I fixed it

960×401 33.7 KB

6

working like charm

7

Please, can you post the full finished code ?