Turn on relay for amount of time by continuous input

Question

I have a project having two input status

• first the input is not continuous the output buzzer relay will be on for 10 seconds and then turned off or it can be off directly by push button

• the second state if the input is continuous the output buzzer relay will be on for 10 seconds and then turned off or it can be off directly by push button

I made this code but it does not work can anyone suggest an edit without using millis() because it will crash after 49 days and without using delay function.

Note that the device will work 24 hours / 365 days.

const int input1 = 19;
const int input2 = 36;
const int relay1 = 10;
const int relay2 = 21;
const int reset = 40;
const int buzzerreset = 45;
const int buzzerrelay = 46;

int buttonState1 = 0;    //for input1
int buttonState2 = 0;    //for input2
int buttonState3 = 0;    //for pushbutton
int buttonState4 = 0;    //for buzzer reset
int b4 = 0;              //for buzzer reset

void setup() {
  pinMode(relay1, OUTPUT);
  pinMode(relay2, OUTPUT);
  pinMode(buzzerrelay, OUTPUT);
  pinMode(input1, INPUT);
  pinMode(input2, INPUT);
  pinMode(reset, INPUT);
  pinMode(buzzerreset, INPUT);

  digitalWrite(relay1, LOW);
  digitalWrite(relay2, LOW);
  digitalWrite(buzzerrelay, LOW);
}

void loop() {
  buttonState1 = digitalRead(input1);
  if (buttonState1 == HIGH) {
    digitalWrite(relay1, HIGH);
    digitalWrite(buzzerrelay, HIGH);
    //delay(10000);
    //digitalWrite(buzzer, LOW);
  }

  buttonState3 = digitalRead(reset);
  if (buttonState3 == HIGH) {
    digitalWrite(relay1, LOW);
    //digitalWrite(buzzer, LOW);
  } else {
    buttonState4 = digitalRead(buzzerreset);

    if ((buttonState4 == HIGH || buttonState1 == HIGH) && b4 == LOW) {
      digitalWrite(buzzerrelay, LOW);
    }
    // while (digitalRead(input1) == HIGH);
    // digitalWrite(buzzerrelay, LOW);

    (buttonState2 = digitalRead(input2));
    if (buttonState2 == HIGH) {
      digitalWrite(relay2, HIGH);
      digitalWrite(buzzerrelay, HIGH);
      //delay(10000);
      //digitalWrite(buzzer, LOW);
    }

    buttonState3 = digitalRead(reset);
    if (buttonState3 == HIGH) {
      digitalWrite(relay2, LOW);
      //digitalWrite(buzzer, LOW);
    } else {
      buttonState4 = digitalRead(buzzerreset);
      if (buttonState4 == HIGH) {
        digitalWrite(buzzerrelay, LOW);
      }
      //while (digitalRead(input2) == HIGH);
      //digitalWrite(buzzerrelay, LOW);
    }
  }
}

Answer 1

I would suggest having a buzzerPlaying state, an oldInput state, and a buzzerOffTime (unsigned long millis when you should turn the buzzer off.

Ignore input if buzzerPlaying == true and just check the buzzerOffTime. When buzzerOffTime passes, turn off the buzzer, set buzzerPlaying to false, and start checking the input again.

If the buzzerPlaying == false and input is high:

1. check buzzerPlaying. If it's true, do nothing.

2. If buzzerPlaying is false, check oldInput. If oldInput is high, do nothing (The input has not been reset.) else set buzzerPlaying to true, set oldInput to high, turn on the buzzer, and calculate buzzerOffTime.

If the buzzerPlaying == false and input is low, set oldInput to low (Once the buzzer has stopped playing and the input has dropped low, start looking for more inputs.)

Answer 2

Whatever the inputs do, when one of them first goes HIGH you want the buzzer to sound, stopping after 10 seconds or a button-press, whichever comes first? Then you need something like this:

if any input is HIGH,
   save millis();
   start the buzzer;

   if button is HIGH
      stop the buzzer;
   else if millis() - saved millis() >= 10*1000 millisec),
      stop the buzzer;
end;