int buttonPin2=7;
int LedPin1=8;
int LedPin2=13;

bool buttonState2=0;
bool lastButtonState2=0;
bool LedState1=0;
bool LedState2=1;

unsigned long BeforeTime=0;
unsigned long lastDebounceTime2=0;

int debounceDelay=50;
int Interval = 500;
bool PomocnaHodnota2=0;

void setup() {
pinMode(LedPin1, OUTPUT);
pinMode(LedPin2, OUTPUT);
pinMode(buttonPin2, INPUT);
Serial.begin(9600);
}

void loop() {
  if(millis()-BeforeTime>=Interval)
{
BeforeTime =millis();
digitalWrite(LedPin1,LedState1);
digitalWrite(LedPin2,LedState2);
LedState1=!LedState1;
LedState2=!LedState2;
}

bool reading2 = digitalRead(buttonPin2);
  if (reading2 != lastButtonState2) {
        lastDebounceTime2 = millis();
    }
    if ((millis() - lastDebounceTime2) > debounceDelay) {
        if (reading2 != buttonState2) {
            buttonState2 = reading2;
           if (buttonState2 == HIGH) 
           {
           PomocnaHodnota2=!PomocnaHodnota2; 
           }
           }
    }
    if (PomocnaHodnota2==1){
      Interval=Interval+100;
      PomocnaHodnota2=0;
       Serial.println("nový interval je "+String(Interval));
    }
    lastButtonState2 = reading2;
}