// speedometer goes to 99.99km/h

float time = 1000000;     // speed
float vel = 0;
float itmd = 0;
float itmd2 = 0;             // speed
float itmd3 = 0;
unsigned long count = 0;
float km = 0;
int num = 0;
int cislo = 0;               // start of display values
int cislodesat = 0;
int cislodesat2 = 0;
int cislosto = 0;
int cislosto2 = 0;
int cislotisic = 0;
int zobraz = 0;
int zobrazCislo = 0;
int intermid = 0;
int intermid2 = 0;
int intermid3 = 0;
unsigned long present = 0;
unsigned long past = 0;
unsigned long present2 = 0;
unsigned long past2 = 0;
unsigned long past3 = 0;
unsigned long present4 = 0;
unsigned long past4 = 0;

void setup() {

pinMode(10, OUTPUT);
pinMode(11, OUTPUT);  // digits (pnp)
pinMode(12, OUTPUT);
pinMode(13, OUTPUT);

pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);  // segments (direct)
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(A1, OUTPUT); // decimal point

pinMode(2, INPUT_PULLUP);
pinMode(A0, INPUT_PULLUP);

attachInterrupt(digitalPinToInterrupt(2), zeroing, FALLING);

digitalWrite(3, HIGH);
digitalWrite(4, HIGH);
digitalWrite(5, HIGH);
digitalWrite(6, HIGH);
digitalWrite(7, HIGH);
digitalWrite(8, HIGH);
digitalWrite(9, HIGH);

digitalWrite(10, HIGH);
digitalWrite(11, LOW);
digitalWrite(12, HIGH);
digitalWrite(13, HIGH);

}

void nezobraz() {
digitalWrite(3, HIGH);
digitalWrite(4, HIGH);
digitalWrite(5, HIGH);
digitalWrite(6, HIGH);
digitalWrite(7, HIGH);
digitalWrite(8, HIGH);
digitalWrite(9, HIGH);
}

void zobrazTis() {
  digitalWrite(11, HIGH);
  digitalWrite(12, HIGH);
  digitalWrite(13, HIGH);
  digitalWrite(10, LOW);
}

void zobrazSto() {
  digitalWrite(10, HIGH);
  digitalWrite(12, HIGH);
  digitalWrite(13, HIGH);
  digitalWrite(11, LOW);
}

void zobrazDes() {
  digitalWrite(11, HIGH);
  digitalWrite(10, HIGH);
  digitalWrite(13, HIGH);
  digitalWrite(12, LOW);
}

void zobrazJdn() {
  digitalWrite(11, HIGH);
  digitalWrite(12, HIGH);
  digitalWrite(10, HIGH);
  digitalWrite(13, LOW);
}

void z0() {
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  digitalWrite(8, LOW);
  digitalWrite(9, HIGH);
}

void z1() {
  digitalWrite(3, HIGH);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, HIGH);
  digitalWrite(7, HIGH);
  digitalWrite(8, HIGH);
  digitalWrite(9, HIGH);
}

void z2() {
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, HIGH);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  digitalWrite(8, HIGH);
  digitalWrite(9, LOW);
}

void z3() {
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
  digitalWrite(8, HIGH);
  digitalWrite(9, LOW);
}

void z4() {
  digitalWrite(3, HIGH);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, HIGH);
  digitalWrite(7, HIGH);
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
}

void z5() {
  digitalWrite(3, LOW);
  digitalWrite(4, HIGH);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
}

void z6() {
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
}

void z7() {
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, HIGH);
  digitalWrite(7, HIGH);
  digitalWrite(8, HIGH);
  digitalWrite(9, HIGH);
}

void z8() {
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
}

void z9() {
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
}

void zeroing() {
  time = present - past;
  count = count + 1;
  past = present;
  past3 = present2;
}

void loop() {

    if (num > 9) {
      cislodesat = num / 10;
      cislosto = num / 100;
      cislotisic = num / 1000;
      intermid = cislodesat * 10;
      intermid2 = cislosto * 10;
      intermid3 = cislotisic * 10;
    }

    if (num <= 9) {
      cislodesat = 0;
      cislodesat2 = 0;
      cislosto = 0;
      cislosto2 = 0;
      cislotisic = 0;
      cislo = num;
    }

    if (num > 9 && num <= 99) {
    cislodesat2 = cislodesat - intermid2;
    cislosto2 = cislosto - intermid3;
      cislo = num - intermid;
    }

    if (num > 99 && num <= 999) {
    cislodesat2 = cislodesat - intermid2;
    cislosto2 = cislosto - intermid3;
      cislo = num - intermid;
    }

  if(num >= 999) {
    cislodesat2 = cislodesat - intermid2;
    cislosto2 = cislosto - intermid3;
    cislo = num - intermid;
  }

if(present2 - past2 >= 500) {
itmd = 1000 / time;
itmd2 = itmd * 2194;
itmd3 = itmd2 * 3600;
vel = itmd3 / 1000000;
km = count * 0.002194;
past2 = present2;
}

if(present2 - past3 >= 5000 && time <= 2000000000) {
  time = time + 1000;
  past = present - 200;
}

if(vel >= 99.99) {
  vel = 99.99;
}

if(digitalRead(A0) == HIGH) {
num = vel * 100;
}

if(digitalRead(A0) == LOW) {
num = km * 100;
}

present = millis();      // speed
present2 = millis();     // display refresh, processing delays, non-blocking
present4 = micros();     // display

if(present4 - past4 >= 6600) {
  zobraz = zobraz + 1;
  nezobraz();

switch (zobraz) {

  case 0:
  zobrazCislo = cislotisic;
  zobrazTis();
    break;

  case 1:
  zobrazCislo = cislosto2;
  zobrazSto();
  digitalWrite(A1, LOW);
    break;

  case 2:
  zobrazCislo = cislodesat2;
  digitalWrite(A1, HIGH);
  zobrazDes();
    break;

  case 3:
  zobrazCislo = cislo;
  zobrazJdn();
    break;

}

  past4 = present4;
}

if(zobraz >= 4) {
  zobraz = -1;
}

switch (zobrazCislo) {

  case 0:
    z0();
    break;

  case 1:
    z1();
    break;

  case 2:
    z2();
    break;

  case 3:
    z3();
    break;

  case 4:
    z4();
    break;

  case 5:
    z5();
    break;

  case 6:
    z6();
    break;

  case 7:
    z7();
    break;

  case 8:
    z8();
    break;

  case 9:
    z9();
    break;

}

}