A stopwatch on a M5Atom stack, displaying the time in a binary format on the 5x5 led display. Worked together with @Ash-broccoli

binary_stopwatch.ino

#include "M5Atom.h"

int delayAmt = 1000;

int second_10th = 0;
int second_1st = 0;

int minute_10th = 0;
int minute_1st = 0;

unsigned long millis_start = millis();

uint32_t lastButtonPress = millis();
bool switchRunning = false;
bool isRunning = true;

void setup() {
  Serial.begin(9600);
  // put your setup code here, to run once:
  M5.begin(true, false, true);

  millis_start = millis();

  // int min1 = 9;
  //int binaryMin1[5];
  //convert_to_binary(binaryMin1, min1);


  //display_binary(9, binaryMin1);
}
void loop() {
  M5.update();
  uint32_t lastChange = M5.Btn.lastChange();
  // Serial.print(String(lastChange)+"\n");
  if (lastChange > lastButtonPress) {
    if (switchRunning) {
      Serial.print("pressed\n");
      isRunning = !isRunning;
      if (isRunning) {
        millis_start = millis();
      }
    }
    switchRunning = !switchRunning;
    lastButtonPress = millis();
  }
  if (isRunning) {
    if ((millis() - millis_start) >= 1000) {
      int binary_second_10th[5];
      int binary_second_1st[5];
      convert_to_binary(second_10th, binary_second_10th);
      convert_to_binary(second_1st, binary_second_1st);

      int binary_minute_10th[5];
      int binary_minute_1st[5];
      convert_to_binary(minute_10th, binary_minute_10th);
      convert_to_binary(minute_1st, binary_minute_1st);

      // print the binary array

      display_binary(1, binary_minute_10th);
      display_binary(2, binary_minute_1st);
      display_binary(4, binary_second_10th);
      display_binary(5, binary_second_1st);


      // increment the seconds
      second_1st++;
      if (second_1st == 10) {
        second_1st = 0;
        second_10th++;
      }

      if (second_10th == 6) {
        second_10th = 0;
        minute_1st++;
      }

      if (minute_1st == 10) {
        minute_1st = 0;
        minute_10th++;
      }

      millis_start = millis();
    }
  }
}


void convert_to_binary(int num, int array[5]) {
  int i = 0;
  while (num > 0) {
    array[i] = num % 2;
    num /= 2;
    i++;
  }

  while (i < 5) {
    array[i] = 0;
    i++;
  }
}

void display_binary(int line, int binArr[]) {
  int count = 0;
  if (line > 5) {
    count = 20;
  } else if (line > 1) {
    count = (line - 1) * 5;
  }

  for (int j = 4; j >= 0; j--) {
    if (binArr[j] == 1) {
      M5.dis.drawpix(count, 0xffffff);
    } else {
      M5.dis.drawpix(count, 0x000000);
    }
    count++;
  }
  M5.dis.drawpix(11, 0x03fc28);
  M5.dis.drawpix(13, 0x03fc28);
}