PIR_poll

#!/usr/bin/python3
import os, time
import RPi.GPIO as GPIO

pir_pin = 18

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(pir_pin, GPIO.IN, pull_up_down = GPIO.PUD_DOWN)

current_state = 0
previous_state = 0

while True:
    current_state = GPIO.input(pir_pin)
    if not current_state == previous_state:
        print("Alarm")
        previous_state = current_state
    time.sleep(0.5)