Performing a function after x time

Question

What can I use to perform a function in the loop if none of the other conditions in the loop and their code have been executed after a certain amount of time? Can it be done with a delay, or is there some other function?

Answer 1

I don't think it's possible to implement since the Arduino does not have an internal clock.

EDIT : It is possible to use the millis() function to calculate an amount of time since the start of the board:

unsigned long previousMillis = 0; // last time update
long interval = 2000; // interval at which to do something (milliseconds)

void setup(){
}

void loop(){
  unsigned long currentMillis = millis();

  if(currentMillis - previousMillis > interval) {
     previousMillis = currentMillis;  

     // do something
  }
}