Exit function after specified time

Forum 2005-2010 (read only) Software Syntax & Programs
1

Hi,

Im not sure if someone already asked this before, but I was wondering if I could break from a function if the function doesn't fully execute in say 6 seconds.

Basically this is the function which will be running to calculate the time it takes a magnet to pass once over a reed switch:

void tripuino::rech(unsigned long *timestart, unsigned long *timeend){
    while (digitalRead(3) == HIGH){
    }
    *timestart = millis();
    while (digitalRead(3) == LOW){
    }
    while (digitalRead(3) == HIGH){
    }
    *timeend = millis();
}

I want the function to stop executing if it takes longer than six seconds to indicate that the speed is roughly zero in the rest of my code. Would I need to use an interrupt or is there another way of achieving my goal?

Thanks in advance

2

You should move timestart declaration before the first while loop. Then, in each while loop, check the condition AND check that now (millis()) minus the start time is less than 6 seconds.