Arduino controlled DPDT with time out program

[alto777]

@rwco ... I see this is creeping back in

  // Check if millis rolled over
  if (start_time2 > time_now2) start_time2 = millis();

There is no need to check for millis() rollover.

This

  time_now = millis();
  if (time_now - start_time > delay_time)
  {
    // Stop the actuator after delay_time 
    digitalWrite (RelayF_pin, LOW);
    digitalWrite (RelayR_pin, LOW);
  }

is how to do timing properly. It will function perfectly for intervals shorter than 49.7 days...

I have removed a variable and the comment, which leaps off the page to experienced readers and the rollover test and "solution", which analysis and testing show is not what you want and nothing you need to do.

In my version, both timers follow the idiomatic pattern

  time_now = millis();
  if (time_now - start_time > delay_time)
  {
    // Stop the actuator after delay_time. Once

    if (digitalRead(RelayF_pin) == HIGH || digitalRead(RelayR_pin) == HIGH)
    {
      Serial.println("        AB timeout STOP");
      digitalWrite (RelayF_pin, LOW);
      digitalWrite (RelayR_pin, LOW);
    }
  }

Since I wanted to print the STOP message only once, I only do so if either of the following lines would actually turn off something that was on.

Here's three competent articles on the subject.

Millis() roll over

I need to delay an action by between 20 to 120 seconds on a esp32. I understand the millis() function can do this but I am unsure how the 49 day roll over works. It is my understanding that there is no telling what the initial value is. It is only used as a reference to compare against. If that assumption is true one could see a roll over at anytime. How is this handled or am I look at this wrong?

​How to deal with the millis rollover

Gammon Forum : Electronics : Microprocessors : millis() overflow ... a bad...

As I said, it's a common misconception. It has been done to death multiple times on these fora, always ending with the same conclusion and usually convincing ppl who come here worrying about it, or have been told here they must.

a7