PIR Motion Controlled Relay Using Arduino Nano!

/*
* PIR sensor tester
*/
 
int relayPin = 3; // choose the pin for the relay
int pirSensorPin = 2; // choose the input pin (for PIR sensor)
int pirState = true; // we start, assuming no motion detected
int val = 0; // variable for reading the pin status
int minimummSecsLowForInactive = 5000; // If the sensor reports low for
// more than this time, then assume no activity
long unsigned int timeLow;
boolean takeLowTime;
 
//the time we give the sensor to calibrate (10-60 secs according to the datasheet)
int calibrationTime = 30;
 
void setup() {
pinMode(relayPin, OUTPUT); // declare LED as output
pinMode(pirSensorPin, INPUT); // declare sensor as input
 
Serial.begin(9600);
 
//give the sensor some time to calibrate
Serial.print("calibrating sensor ");
for(int i = 0; i < calibrationTime; i++){
Serial.print(".");
delay(1000);
}
Serial.println(" done");
Serial.println("SENSOR ACTIVE");
delay(50);
}
 
void loop(){
  
val = digitalRead(pirSensorPin); // read input value
if (val == HIGH) { // check if the input is HIGH
  
digitalWrite(relayPin, HIGH); // turn LED ON
if (pirState) {
// we have just turned on
pirState = false;
Serial.println("Motion detected!");
// We only want to print on the output change, not state
delay(50);
}
takeLowTime = true;
} 

else {
digitalWrite(relayPin, LOW); // turn LED OFF
 
if (takeLowTime){
timeLow = millis();
takeLowTime = false;
}
 
if(!pirState && millis() - timeLow > minimummSecsLowForInactive){
pirState = true;
Serial.println("Motion ended!");
delay(50);
}
 
}
}