ls /dev/video*

#encoding=utf-8
import RPi.GPIO as GPIO
import cv2
import time
import os
 
GPIO.setmode(GPIO.BCM)
GPIO.setup(18,GPIO.OUT)
 
camera = cv2.VideoCapture(0)
if camera is None:
 print('please connect the camera')
 exit()
 
fps = 30 
pre_frame = None
 
led = False
 
while True:
 start = time.time()
 res, cur_frame = camera.read()
 if res != True:
 break
 end = time.time()
 seconds = end - start
 if seconds < 1.0/fps:
 time.sleep(1.0/fps - seconds)
 
 cv2.namedWindow('img',0);
 #cv2.imshow('img', cur_frame)
 key = cv2.waitKey(30) & 0xff
 if key == 27:
 break
 
 gray_img = cv2.cvtColor(cur_frame, cv2.COLOR_BGR2GRAY)
 gray_img = cv2.resize(gray_img, (500, 500))
 gray_img = cv2.GaussianBlur(gray_img, (21, 21), 0)
 
 if pre_frame is None:
 pre_frame = gray_img
 else:
 img_delta = cv2.absdiff(pre_frame, gray_img)
 thresh = cv2.threshold(img_delta, 25, 255, cv2.THRESH_BINARY)[1]
 thresh = cv2.dilate(thresh, None, iterations=2)
 
 contours, hierarchy = cv2.findContours(thresh.copy(),cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)
 for c in contours:
  if cv2.contourArea(c) < 1000:
  continue
  else:
 (x,y,w,h) = cv2.boundingRect(c)
 cv2.rectangle(cur_frame,(x,y),(x+w,y+h),(0,255,0),2)
 
 print("something is moving!!!")
 led = True
 if led == True:
 for i in range(30):
 GPIO.output(18,GPIO.HIGH)
 time.sleep(0.03)
 GPIO.output(18,GPIO.LOW)
 time.sleep(0.03)
  break
 
 cv2.imshow('img', cur_frame) 
 pre_frame = gray_img
 
camera.release()
cv2.destroyAllWindows()