Set pins to LOW over time

Question

I've written a simple sketch that adds threshold to an PIR sensor. If the PIR sensor sends 3 HIGH ex. HIGH...LOW...HIGH...LOW...HIGH (The LOW == no movement) it will trigger and alarm.

I want to reset the counter of HIGHs if there's no movement detected. The problem is the loop will get delayed if I put it inline. My code: (Don't mind my code, I'm pretty newbie)

int calibrationTime = 30;
int pirPin = 5;
int ledPin = 6;
int sensorState;
int stateCount = 0; //How much movement is detected
int stateThreshold = 3; //THRESHOLD
bool isSensorHigh;

void setup() {
  Serial.begin(9600);
  pinMode(pirPin, INPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  digitalWrite(pirPin, LOW);
  Serial.print("calibrating sensor ");
  for (calibrationTime; calibrationTime > 0; calibrationTime--) {
    Serial.print(calibrationTime);
    delay(1000);
  }
  Serial.println(" done");
  Serial.println("SENSOR ACTIVE");
  delay(50);
}
void loop() {
  sensorState = digitalRead(pirPin);
  //Serial.println(sensorState);
  if (sensorState == 1) {
    isSensorHigh = true;
  }
  if (sensorState == 0 && isSensorHigh == true) {
    isSensorHigh = false;
    stateCount++;
  }
  //Set pins 2,3,4 here to LOW if there's no movement detected over time
  if (stateThreshold == 3) {
    switch (stateCount) {
      case 1:
        digitalWrite(2, HIGH);
        break;
      case 2:
        digitalWrite(3, HIGH);
        break;
      case 3:
        digitalWrite(4, HIGH);
        break;
    }
  }
  if (stateCount == stateThreshold) {
    blinkLeds();
    delay(3000);
    digitalWrite(2, LOW);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
    digitalWrite(ledPin, LOW);
    stateCount = 0;
  }
  Serial.println(stateCount);
  delay(150);
}

void blinkLeds() {
  for (int x = 4; x > 0; x--) {
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, HIGH);
    delay(1000);
    digitalWrite(2, LOW);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
    delay(1000);
  }
}

Answer 1

Use millis() instead on delay. Ref: https://www.arduino.cc/en/reference/millis