How can ı use counter with Arduino millis function

Question

I want to make a timercounter with millis function. I wrote a code but ıt does not count 10seconds barely. There is sth wrong but ı could not see. My aim after pushing button, 10seconds later it must turn off. But ıt turns off not certainly 10s, sometimes 5-8-9 it is changable.

#define  button            2
#define  relay_drive       13 
unsigned long current_time , last_time=0 ;
unsigned long _10scounter;
int _10s_Flag;
void setup()
  
{

  pinMode(button, INPUT);
  pinMode(relay_drive, OUTPUT);
}

void loop()
{
 milis_interrupt();
 if (!digitalRead(button)) {digitalWrite(relay_drive, HIGH);  _10s_Flag = 0;} //pull up res
 
 if(_10s_Flag & digitalRead(relay_drive))
 {
 _10s_Flag = 0;
 digitalWrite(relay_drive, LOW);
 }
}


void milis_interrupt(){
  current_time= millis(); //millis
 if(current_time>last_time){
if(_10scounter>=10000) {_10scounter=0; _10s_Flag = 1;}
if(_10scounter<10000)  _10scounter++;
last_time = current_time;
}
  }

Could you help me with my code, dear friends.

Answer 1

This line:

if(current_time>last_time)

will most always be true.

What you want is something like:

if(current_time - last_time > 10000)

which checks that the difference in times has exceeded your limit of 10 secs onds.

/regards