/*
  Arduino | coding-help
  Need help with alarm setup.

  Harbinger July 7, 2025 — 9:37 AM

  Hello all, thank you very much for reading.

  I am working on a project to take the sound produced by a
  buzzer from my NVR system by using a microphone sensor, then
  i need the Arduino to activate a relay that will power
  the 30 watt siren.
  I have a separate power supply for the siren so it won't be
  running off the Arduino.

  I am more mechanically inclined and have been unable to find
  the required code online.

  I would truly appreciate some help with the required code.

  Regards
*/

const unsigned long HOLD_TIME = 30;  // seconds to stay on
const int SENSOR_PIN = 12;
const int RELAY_PIN = 11;

unsigned long triggeredTime = 0;
unsigned long holdTime = HOLD_TIME * 1000; // milliseconds to stay on
bool isTriggered = false;

void setup() {
  Serial.begin(9600);
  pinMode(SENSOR_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
}

void loop() {
  int senseValue = digitalRead(SENSOR_PIN);

  if (senseValue == LOW)  { // or HIGH, depends on sensor
    isTriggered = true;
    triggeredTime = millis();
  }

  if (millis() - triggeredTime >= holdTime)  {
    isTriggered = false;
  }

  if (isTriggered)  {
    digitalWrite(RELAY_PIN, HIGH);
  } else {
    digitalWrite(RELAY_PIN, LOW);
  }

}